Miracle-dz/UniFAR-FTUs huggingface dataset:
Low-platinum and platinum-free catalysts for the oxygen reduction reaction at fuel cell cathodes

Fuel cell reactions invariably involve an oxygen reduction reaction (ORR) at the cathode, which is one of the main rate-decreasing steps on platinum (Pt)-catalysts in the water formation reaction and energy conversion efficiency in polymer electrolyte membrane fuel cells (PEMFCs). The Pt scarcity and cost have led to the development of alternative catalyst materials for fuel cell applications. This paper reviews ORR catalysts with regard to their classification, mechanism, activity and performances. From conventional Pt-based catalysts to non-noble metal or bio-inspired catalysts, we show how significant progresses were made in ORR catalysis.
Description and crystal structure of a new mineral – plimerite, ZnFe3+4(PO4)3(OH)5 – the Zn-analogue of rockbridgeite and frondelite, from Broken Hill, New South Wales, Australia

Abstract Plimerite, ideally ZnFe3+4(PO4)3(OH)5, is a new mineral from the Block 14 Opencut, Broken Hill, New South Wales. It occurs as pale-green to dark-olive-green, almost black, acicular to prismatic and bladed crystals up to 0.5 mm long and as hemispherical aggregates of radiating acicular crystals up to 3 mm across. Crystals are elongated along [001] and the principal form observed is {100} with minor {010} and {001}. The mineral is associated with hinsdalite-plumbogummite, pyromorphite, libethenite, brochantite, malachite, tsumebite and strengite. Plimerite is translucent with a pale-greyish-green streak and a vitreous lustre. It shows an excellent cleavage parallel to {100} and {010} and distinct cleavage parallel to {001}. It is brittle, has an uneven fracture, a Mohs' hardness of 3.5-4,D(meas.) = 3.67(5) g/cm3 and D(calc.) = 3.62 g/cm3 (for the empirical formula). Optically, it is biaxial negative with α = 1.756(5), β = 1.764(4), γ = 1.767(4) and 2V(calc.) of −63°; pleochroism is X pale-greenish-brown, Y pale-brown, Z pale-bluish-green; absorption Z > X > Y; optical orientation XYZ = cab. Plimerite is orthorhombic, space group Bbmm, unit-cell parameters: a = 13.865(3) Å, b = 16.798(3) Å, c = 5.151(10) Å, V = 1187.0(4) Å3 (single-crystal data) and Z = 4. Strongest lines in the X-ray powder diffraction pattern are [d (Å), I, hkl]: 4.638, (50), (111); 3.388, (50), (041); 3.369, (55), (131); 3.168, (100), (132); 2.753, (60), (115); 2.575, (90), (200); 2.414, (75), (220); 2.400, (50), (221); 1.957, (40), (225). Electron microprobe analysis yielded (wt.%): PbO 0.36, CaO 0.17, ZnO 20.17, MnO 0.02, Fe2O329.82, FeO 2.98, Al2O3 4.48, P2O5 32.37, As2O5 0.09, H2O (calc) 6.84, total 97.30 (Fe3+/Fe2+ ratio determined by Mössbauer spectroscopy). The empirical formula calculated on the basis of 17 oxygens is Ca0.02Pb0. 01Zn1.68Fe2+0.28Fe3+2.53Al0. 60P3.09As0. 01O17.00H5. 15. The crystal structure was solved by direct methods and refined to an R1 index of 6.41% for 1332 observed reflections from single-crystal X-ray diffraction data (Mo-Kα radiation, CCD area detector). The structure of plimerite is isotypic with that of rockbridgeite and is based on face-sharing trimers of (Mɸ6) octahedra which link by sharing edges to form chains, that extend in the b-direction. Chains link to clusters comprising pairs of corner-sharing (Mɸ6) octahedra that link to PO4 tetrahedra forming sheets parallel to (001). The sheets link via octahedra and tetrahedra corners into a heteropolyhedral framework structure. The mineral name honours Professor Ian Plimer for his contributions to the study of the geology of ore deposits.
Formation of complex organic molecules in cold objects: the role of gas-phase reactions

While astrochemical models are successful in reproducing many of the observed interstellar species, they have been struggling to explain the observed abundances of complex organic molecules. Current models tend to privilege grain surface over gas phase chemistry in their formation. One key assumption of those models is that radicals trapped in the grain mantles gain mobility and react on lukewarm (>30 K) dust grains. Thus, the recent detections of methyl formate (MF) and dimethyl ether (DME) in cold objects represent a challenge and may clarify the respective role of grain surface and gas phase chemistry. We propose here a new model to form DME and MF with gas phase reactions in cold environments, where DME is the precursor of MF via an efficient reaction overlooked by previous models. Furthermore, methoxy, a precursor of DME, is also synthetized in the gas phase from methanol, which is desorbed by a non-thermal process from the ices. Our new model reproduces fairy well the observations towards L1544. It also explains, in a natural way, the observed correlation between DME and MF. We conclude that gas phase reactions are major actors in the formation of MF, DME and methoxy in cold gas. This challenges the exclusive role of grain-surface chemistry and favours a combined grain-gas chemistry.
Hyphenated techniques of thermal analysis for characterisation of soil humic substances

Our aim was to investigate the thermal behaviour of humic substances extracted from temperate and tropical soils by means of hyphenated techniques of thermal analysis (e. g. simultaneous thermal analysis DSC/TG coupled with mass spectrometry, MS, for the analysis of evolved gas, EGA) in order (i) to verify whether the chemical composition of isolated humic substances also reflected the differences in microbial parameters previously measured in related soil samples and (ii) to identify suitable indices of thermal stability. Our results show that the investigation of humic substances by thermal methods can provide information on soil organic matter dynamics. Differences in thermal behaviour between the two groups of soils were found. The indices of thermal stability here proposed, IR (index of thermal recalcitrance), and ID (index of thermal decomposability) clearly showed that in humic substances from tropical soils the thermally recalcitrant organic fraction dominated, whilst in temperate humic substances the opposite held. This agrees with previous results on the microbial dynamics and organic matter turnover of the respective soils and indicates that these indices of thermal stability could represent a useful tool in soil environmental quality investigations.
Solubility and dye-binding properties of quaternized and peroxidase-polymerized kraft lignin

The ability of cationic Kraft lignin to function as a flocculant for decolorization of textile wastewaters was examined. Kraft lignin was quaternized with high efficiency in alkaline solution with 3-chloro-2-hydroxypropyl-trimethylamonium chloride. The product formed was separated into two fractions arbitrarily based on their aqueous solubility at pH 7. The pH 7-soluble fraction was soluble over the pH 2 to 13 range. The pH 7-insoluble fraction was soluble at low ( pH 12). Treatment of the pH 7-soluble quaternized lignin fraction with soybean peroxidase and hydrogen peroxide under nitrogen produced a soluble, high molecular weight polymer, as determined by ultrafiltration analysis. Peroxidase treatment of the pH 7-insoluble fraction at pH 3 produced a material not completely soluble at any pH, probably by modifying the lignin structure but not necessarily by increasing its molecular weight. All quaternized lignin fractions were demonstrated to bind Orange II and hydrolyzed Reactive R.
Failure analysis in ITO-free all-solution processed organic solar cells

In this paper we discuss a problem-solving methodology and present guidance for troubleshooting defects in ITO-free all-solution processed organic solar cells with an inverted cell architecture. A systematic approach for identifying the main causes of failures in devices is presented. Comprehensive analysis of the identified failure mechanisms allowed us to propose practical solutions for further avoiding and eliminating failures in all-solution processed organic solar cells. Implementation of the proposed solutions has significantly improved the yield and quality of all-solution processed organic solar cells.
Autonomous Learning of the Robot Kinematic Model

Robotics systems are becoming more and more autonomous and reconfigurable. In this context, the design of algorithms capable of deriving kinematics and dynamics models directly from data could be particularly useful. In this article, we present an algorithm that learns a forward kinematics model of a robot starting from a time series of visual observations. Our strategy can be applied to any robot with serial kinematics composed of revolute and prismatics joints. First, the algorithm identifies the robot kinematic structure, i.e., a high-level description of the robot geometry that defines the connections between the rigid-bodies composing the robot. Then, the algorithm derives the forward kinematics relying on a Gaussian process (GP) model. More precisely, the GP model is based on a polynomial kernel, defined exploiting the kinematic structure previously identified. The effectiveness of the proposed solution has been tested via extensive Monte Carlo simulations, as well as via experiments on a real UR10 robot.
Direct synthesis of dextran-coated superparamagnetic iron oxide nanoparticles in a capillary-based droplet reactor

We describe the controlled synthesis of dextran-coated superparamagnetic iron oxide nanoparticles (SPIONs) using a stable passively-driven capillary-based droplet reactor. High quality highly crystalline particles were obtained with a narrow size distribution of mean diameter 3.6 nm and standard deviation 0.8 nm. The particles were evaluated for use in MRI, and found to exhibit a large saturation magnetisation of 58 emu/g and a high T2 relaxivity of 66 mM−1s−1 at 4.7 T, signifying good MRI contrast enhancement properties.
Methodology for Analyzing Dissolved Oxygen Consumption in Benthic Chambers

AbstractDissolved oxygen (DO) consumption in the sediments of natural aquatic ecosystems occurs by mass flux across the water-sediment interface. This mass flux is determined as either the rate of oxygen consumption in the sediment or the rate of DO diffusion across the diffusive sublayer. The thickness of the diffusive sublayer is determined by the flow conditions in the turbulent water column. Consequently, feedback occurs between the biochemical consumption that occurs in the sediment and the flow that occurs in the water column. Together, these conditions define the DO flux across the water-sediment interface. Benthic chambers have been used to measure this flux in field and experimental conditions. However, these measurements do not account either for the fact that the flow inside a benthic chamber is not representative of field conditions or for the DO consumption in the water column. Thus, they can provide an inaccurate estimation of the sediment DO demanded in the field. This article aims to prese.
Volunteerism Is Associated with Improved Soft Skills of Marine Engineering Students in the Philippines.

We assessed the impact on soft skills in among 60 marine engineering students after completing a 36-month long community service program. A Soft Skills-Graduate Attribute Scale was developed to measure the following outcomes, namely, professional competence, critical thinking skills, communication skills, lifelong learning, social and ethical responsibility, productivity, and interpersonal skills. Our results show that the students who participated regularly in volunteer activities possess significantly higher measures of graduate attributes relating to professional competence, communication skills, and social and ethical responsibility compared to non-regular and first-time volunteers. These specific soft skills were aligned with the expected outcomes based on the program design of the volunteer activities. Our study adds to the growing literature on the value of servicelearning programs in higher education as community-oriented programs can potentially result in improving soft skills and cross-cultural competencies of students, especially in the technical fields.
Optical dissolved oxygen lifetime sensor based on sol-gel immobilisation

The development of an optical fibre sensor for the measurement of dissolved oxygen based on sol-gel immobilisation technology and phase fluorimetric analysis is investigated. The sensor is based on indicator-mediated sensing where the optical properties of an intermediate reagent are modulated in response to the concentration of analyte. The fluorescent lifetime of an oxygen indicator, tris(1, 10-phenanthroline)ruthenium(II) chloride hydrate is shown to be quenched in the presence of dissolved oxygen. Changes in fluorescent lifetime are measured using phase modulation techniques, the phase shift in the fluorescence emission of the fluorophore is measured as a function of the dissolved oxygen concentration. Sol-gel technology is utilised to immobilise the indicator at the distal end of a multi-mode optical fibre using dip-coating techniques. The selection of the sol-gel precursor compound is found to be of critical importance in the performance of the sensor, with organically modified silicates displaying the best performance.
Rate of Burning of Wood (A Simple Thermal Model)

Abstract In the design of reliable fire hazard ratings and effective fire detection/protection systems, a clear understanding of the interaction between the fire and fuel is greatly desirable. While the fuel supplies combustible vapors to the flames, the flames feed heat back to the fuel for more vapors to be generated. Assuming that (a) the temperature profiles in the interior of a wood-like solid heated externally are linear, (b) the solid pyrolyzes abruptly at a critical temperature, (c) the pyrolysis products are removed out of the solid instantaneously upon their release and (d) the thermal properties of char and wood depend only on the solid density but not on temperature, a simple energy balance is made to deduce the influence of surface heat flux, specimen thickness, pyrolysis endothermicity, internal convection and thermal properties (of the virgin solid and char) on the rate of mass loss of an infinite slab and a cylinder in a fire. The predictions are in good agreement with the available experi.
Methods for Analyzing Phenolics in Research

Chromatographic and spectroscopic methods important to the analysis of grape and wine phenolics are described. The developmental history of these methods is presented, and associated enological applications are summarized. [C]hemists interested in polyphenols, in common with the majority of scientists, tackle today’s problems with yesterday’s tools, i.e., current problems are attacked with methods which are inadequate and to that extent are already out of date. [t]he discovery and quick application of new methods or developments and extensions of existing methods is therefore of first importance ([Brown 1964][1]). [1]: #ref-30
Effects of inhaled fine particles and ozone on pulmonary macrophages and epithelia

AbstractThe health effects of oxidant gas mixtures containing fine particles from dilute diesel exhaust were examined using the rat as a laboratory model to determine if the presence of diesel soot particles would worsen the effects observed following exposures to oxidant gases alone. The study was designed to simulate an environmental scenario of acute and repeated exposures to polluted ambient atmospheres such as those that occur in southern California, where automotive emissions contribute to the production of oxidant gases such as ozone (O3) and nitrogen dioxide (NO2). Dilute diesel exhaust (scrubbed of sulfur dioxide, SO2, and carbon monoxide, CO), containing 250 or 500 μglm3 diesel soot particles and nitric oxide (NO), was mixed with 0.4 or 0.6 ppm O3, respectively. Chemical reactions within the mixture converted all NO to NO2 and nitric acid (ranging from 110 to 260 uglm3). Therefore, to determine the potential health impact of the particles, the effects of the diesel soot mixture were compared wit.
EFFECTS OF SALINITY STRESS ON THE PHOTOSYNTHESIS OF Wolffia arrhiza AS PROBED BY THE OJIP TEST

In the present study, we investigated the effects of salinity stress, one of the main stress in polluted water bodies, on the photosynthetic activity of Wolffia arrhiza. High salinity stress (1-4%) significantly decreased photosynthetic CO2 assimilation activity, while the chlorophyll a, chlorophyll b and carotenoid contents were not affected after treatment with salinity stress for 24 h. The fluorescence yields at phases J, I and P were clearly decreased by salinity stress above 1%, and the addition of DCMU to the control resulted in the transformation of an O-J-I-P ris e into an 04 rise. Salinity stress decreased the quantum yield of primary photochemistry (phi Po), the quantum yield of electron transport (phi Eo) and the efficiency per trapped excitation (Psi o) in Wolffia arrhiza simultaneously; the number of active PSII reaction centers per excited cross section (RC/CS), the total number of active reaction centers per absorption (RC/ABS) and the performance index of PSII (PIABS and PICS) were also reduced by salinity. These results indicated that the effects of salinity stress on the photosynthesis of Wolffia arrhiza may function by the inhibition electron transport and inactivation of the reaction centers, but the inhibition may occur in the electron transport pathway at the donor and acceptor sides of PSII in Wolffia arrhiza, which is different to that of salt-resistant plants.
Alterations in picual extra virgin olive oils under different storage conditions

Storage conditions can affect the stability of extra virgin olive oil, with adverse results on quality. The aim of this study is to examine changes in the chemical composition and sensory characteristics of the oil resulting from prolonged storage at different temperatures and depending on the type of container. The influence on the quality of the oil was also considered, based on the analysis of quality parameters, the total phenol contents, changes in minority compounds, the variation of the trolox equivalent antioxidant capacity values (TEAC) and sensory features. At both room temperature (RT) and refrigerated temperature, all container types had the same surface area of exposure to light and air. All the oils stored showed losses in both qualitative properties and minor components, as well as antioxidant capacity and sensory features. This was especially true for oils stored in polyethylene terephthalate and glass, but less so for those stored in Tetra-Brik®.
An investigation of the equilibrium of the reaction {L-aspartate(aq)+2-oxoglutarate(aq)=oxaloacetate(aq)+L-glutamate(aq)}

Apparent equilibrium constants have been measured for the following biochemical reaction:L-aspartate(aq) + 2-oxoglutarate(aq) = oxaloacetate(aq) +L-glutamate(aq). This reaction, catalysed by aspartate transaminase, was studied over the ranges 283.15≤T/K≤303.15, 6.94≤pH≤7.13, and 0.163≤Im/(mol·kg−1)≤0.167, whereTis temperature andImis ionic strength. The instability of the oxaloacetate in solution required the use of an experimental procedure that was brief. Thus, the procedure used was to measure the change in the chromatographic response ΔRof the oxaloacetate chromatographic peak that accompanied the reaction. Values of ΔRwere measured for several solutions under near equilibrium conditions. The chromatographic response ΔRis expected to be zero for a solution that is at equilibrium with regard to the above reaction and prior to the addition of the enzyme. The results were used to calculate the standard molar Gibbs energy change ΔrGm°=(4.82±0.21) kJ·mol−1, the equilibrium constantK=(0.143±0.012), the standard molar enthalpy change ΔrHm°=(1.9±2.9) kJ·mol−1, and the standard molar entropy change ΔrSm°=− -03(10±10) J·K−1·mol−1for the following chemical reference reaction atT=298.15 K andIm=0:L-aspartate−(aq) + 2-oxoglutarate2−(aq) = oxaloacetate2−(aq) +L-glutamate−(aq). Under near physiological conditions (T= 311.15 K, pH = 7.0,Im= 0.25 mol·kg−1) the apparent equilibrium constantK′ for the overall biochemical reaction is calculated to have the value 0.147; the standard transformed Gibbs energy change ΔrGm′°=4.96 kJ·mol−1under these conditions.
An Evaluation of Single Phase Ceramic Formulations for Plutonium Disposition

Ceramics are promising potential hosts for the immobilization of actinide containing wastes. Work has been reported in the literature on multiphase systems, such as SYNROC [1], and on single phase systems such as pyrochlores [2] and zirconia [3], but assessment of the different waste-forms by direct comparison of literature data is not always easy due to the different processing and fabrication routes employed. In this study a potential range of different ceramic systems were investigated for plutonium disposition using the same processing scheme. Durable actinide containing minerals exist in nature and provided excellent target phases for the titanate, zirconate, silicate and phosphate based formulations examined here [4]. The Ce solid solution limits for each particular substitution mechanism were established and the processing parameters required to produce high quality ceramic specimens were optimised. Importantly, this was achieved within the constraints of a generic processing route suitable for fabrication of Pu bearing samples. (authors)
Synthesis of porous hollow Fe3O4 beads and their applications in lithium ion batteries

Porous hollow Fe3O4 beads constructed with rod-shaped Fe3O4 nanoparticles were synthesized via a facile solvothermal route. The formation mechanism of the obtained Fe3O4 beads was proposed on the basis of oriented assembly and Ostwald ripening. The as-prepared Fe3O4 beads had promising applications as lithium ion battery anodes, which showed a reversible specific capacity of 500 mAh g−1 after 50 cycles at 100 mA g−1. After being decorated with a carbon coating layer, the Fe3O4/C composite beads showed an enhanced capacity of 700 mAh g−1 after 50 cycles at 100 mA g−1. Such a satisfactory electrochemical performance was due to several factors of the Fe3O4/C composite beads including high theoretical capacity of Fe3O4, nanosized active Fe3O4 particles, hollow porous structure that mitigated the volume change problem, and carbon coating layer that enhanced both the electronic conductivity and structure integrity.
Polymer “Clicking” by CuAAC Reactions

The CuAAC "click" reaction has developed as one of the most useful and widely employed reactions in ligation within polymer chemistry. This is due to the unique properties of the Cu(I) catalysis which renders the reaction quantitative even at low concentrations, orthogonal with other chemistries and extremely robust. The formed triazole on the other hand is of intermediate polarity and chemically and biochemically "invisible", and the CuAAC provides the ideal "click" reaction for stitching together polymer architectures of unprecedended complexity as was it molecular LEGO. The CuAAC "clicking" in polymer chemistry is increasing exponentially and lead to highly defined polymer materials with novel properties.
Comparison of microwave digestion with block digestion for selenium and boron analysis in plant tissues

Abstract Microwave digestion and block digestion of selected plant tissues, including National Institute of Standards and Technology (NIST) Standard Reference Materials, were conducted and evaluated for their effectiveness in the determination of selenium (Se) and boron (B). With microwave digestion, two major parameters were manipulated for digesting botanical materials, microwave energy power profiles (power, time, and pressure) and volume of chemical reagents. Results show that microwave digestion is at least four hours faster than block digestion. However, the recovery rates for Se and B are 20–30% lower by microwave digestion if there is no predigestion and the inappropriate volume and combination of chemical reagents are used. The optimal combinations for microwave digestion of the tested parameters are as follows: for Se, the 0.25 g of sample material is predigested for fourhours with 2 mL nitric acid (HNO3), 2 mL 30% hydrogen peroxide (H2O2), and 1 mL H2O. The microwave is set at 95% power and pre.