Miracle-dz/UniFAR-FTUs huggingface dataset:
Net CO2 exchange rates in three different successional stages of the

The net ecosystem exchange (NEE) of successional stages of the Abies -dominated dark taiga was measured in central Siberia (61°N 90°E) during the growing season of the year 2000 using the eddy covariance technique. Measurements started before snow melt and canopy activity in spring on day of year (DOY) 99 and lasted until a permanent snow cover had developed and respiration had ceased in autumn DOY 299. Three stands growing in close vicinity were investigated: 50 yr-old Betula pubescens (“Betula stand”, an early successional stage after fire), 250 yr-old mixed boreal forest, representing the transition from Betula -dominated to Abies -dominated canopies, and 200-yr-old Abies sibirica (“Abies stand”, representing a late successional stage following the mixed boreal forest). The mixed boreal forest had a multi-layered canopy with dense understory and trees of variable height and age below the main canopy, which was dominated by Abies sibirica , Picea obovata and few old Betula pubescens and Populus tremula trees. The Abies stand had a uniform canopy dominated by Abies sibirica . This stand appears to have established not after fire but after wind break or insect damage in a later successional stage. The stands differed with respect to the number of days with net CO 2 uptake (Betula stand 89 days, mixed boreal forest 109 days, and Abies stand 135 days), maximum measured LAI (Betula 2.6 m 2 m −2 , mixed boreal forest 3.5 m 2 m −2 and Abies stand 4.1 m 2 m −2 ) and basal area (Betula stand 30.2 m 2 ha −1 , mixed boreal forest 35.7 m 2 ha −1 , and Abies stand 46.5 m 2 ha −1 ). In the mixed boreal forest, many days with net daytime CO 2 release were observed in summer. Both other sites were almost permanent sinks in summer. Mean daytime CO 2 exchange rates in July were −8.45 μmol m −2 s −1 in the Betula stand, −4.65 μmol m −2 s −1 in the mixed boreal forest and −6.31 μmol m −2 s −1 in the Abies stand. Measured uptake for the growing season was −247.2 g C m −2 in the Betula stand, −99.7 g C m −2 in the mixed boreal forest and −269.9 g C m −2 in the Abies stand. The total annual carbon uptake might be slightly lower (i.e. less negative) due to some soil respiration under snow in winter. The study for the first time demonstrates that old forests in the “Dark Taiga” are carbon sinks and that sink activity is very similar in late and early successional stages. Canopy and crown structure with associated self-shading and available radiation are suggested as possible causes for the observed differences. DOI: 10.1034/j.1600-0889.2002. 01351.x
Identifying Spinel Phases in Nearly Monodisperse Iron Oxide Colloidal Nanocrystal

Nearly monodisperse iron oxide colloidal nanocrystals prepared by nonhydrolytic high-temperature solution method were obtained with two different sizes and degrees of oxidation. The characterization of the structural features of the nanocrystals was performed by a multitechnique approach including transmission electron microscopy, X-ray diffraction and X-ray absorption spectroscopy, energy filtered electron microscopy imaging, and SQUID magnetometry. The different techniques provided complementary information on the local oxidation state of iron in the iron oxide nanoparticles, the stability of the phases, the exact crystal structure, and the compositional homogeneity. X-ray diffraction, transmission electron microscopy, and extended X-ray absorption spectroscopy show that the addition of oxidizer to the iron precursor gives rise to monodisperse polycrystalline nanoparticles made out of FeO plus a spinel phase. X-ray absorption near-edge structure, which is very sensitive to the oxidation state and local .
Alignment-induced reconfigurable walls for patterning and assembly of liquid crystal skyrmions

Skyrmions have attracted rapidly growing interest due to their topological properties and unique aspects for potential novel applications such as data storage and soft robotics. They can also serve as key elements for materials by design, self-assembly, and functional soft materials. While not real particles, these skyrmions behave like particles-they interact with each other and can be actuated by means of electric field, surface anchoring, and light. On the other hand, they are field configurations which have properties not possessed by real particles. Here, we show that, by means of alignment induced attractive and repulsive walls, skyrmions in chiral nematic liquid crystals can be precisely controlled and programmed to serve as suitable building blocks for the realization of the above goals. Our work may stimulate new experimental efforts and concomitant applications in this direction.
The response of an h.f. moisture probe to soluble salts

The h.f. capacitance response of a probe in aqueous solutions of sodium chloride has been studied as a function of the conductance. The results show that there is an optimum cable length, less than the half wavelength, at which the apparent capacitance is least affected by the addition of sodium chloride, and that the effect can be further reduced by suitable cable design. The results are interpreted in terms of transmission-line theory. As a result of this work two possible ways of measuring moisture in building materials are suggested, and some results are given for gypsum plaster and a dense mortar. Maximum errors of 0·05 volume moisture fraction have been achieved for gypsum plaster and for dense mortar when the pore liquid at saturation was 0·05 M and 0·1 M respectively with respect to sodium chloride.
Mixed Solids Distribution in Stirred Vessels: Experiments and Computational Fluid Dynamics Simulations

The distribution of dilute, mixed solids in Newtonian fluids in a baffled vessel stirred with multiple impellers has been studied experimentally and simulated by means of computational fluid dynamics. For the sake of experimental simplicity, fractions of two solids of different densities and equal size have been used. The experimental part, which was primarily intended to provide data for the validation of the simulation procedure, showed that the two phases act independently and that simple distribution superposition holds true. The computational approach is an extension of that already used for the calculation of monodisperse particle distribution in stirred vessels and is based on the solution of sets of RANS equations, one for each of the phases involved in the process coupled with the “homogeneous” k−e model for closure. The sliding grid method has been selected for the simulation of the baffled vessel. As in the case of a single solid fraction, the momentum transfer between each solid phase and the .
Corrosion Inhibition Propargyl Alcohol on Low Alloy Cr Steel in 0.5 M H2SO4 in the Absence and Presence of Potassium Iodide

The corrosion and inhibition behaviors of low alloy Cr steel in sulfuric acid in the presence of propargyl alcohol (PA) and potassium iodide (KI) have been studied using Electrochemical Impedance Spectroscopy (EIS) and Tafel polarization method. It was found that the inhibition efficiency increased with PA concentration. The addition of potassium iodide to propargyl alcohol in solution increased the inhibition efficiency of propargyl alcohol. A synergistic effect was observed between KI and PA with optimum of concentration of 10 mMol propargyl alcohol + 0.01% potassium iodide. Adsorption of propargyl alcohol alone or in combination with potassium iodide on the metal surface obeyed the Langmuir adsorption isotherm and thermodynamic calculations revealed that that the adsorption of inhibitors were of physical nature. That suggest the presence of iodide ions in solution increases the surface coverage. Key Words : Inhibitor, Propargyl alcohol, Potassium iodide, Synergistic.
Coumarins: Analytical and Preparative Techniques

Coumarins are, nowadays, an important group of organic compounds from natural and synthetic sources, possessing a wide range of pharmacological activities. Coumarins comprise a large group of phenolic substances, which occur in plants as secondary metabolites. On account of the significance of this group of compounds, the development of effective methods for the extraction, separation, qualitative and quantitative analyses, and purification remains of high importance. The purpose of the chapter is to present information about methods of analysis and separation of this important group of naturally occurring compounds. Keywords: coumarins; high performance liquid chromatography; high speed countercurrent chromatography; thin layer chromatography; analytical methods; separation methods
Investigating Active Learning and Meta-Learning for Iterative Peptide Design

Often the development of novel functional peptides is not amenable to high throughput or purely computational screening methods. Peptides must be synthesized one at a time in a process that does not generate large amounts of data. One way this method can be improved is by ensuring that each experiment provides the best improvement in both peptide properties and predictive modeling accuracy. Here, we study the effectiveness of active learning, optimizing experiment order, and meta-learning, transferring knowledge between contexts, to reduce the number of experiments necessary to build a predictive model. We present a multitask benchmark database of peptides designed to advance these methods for experimental design. Each task is a binary classification of peptides represented as a sequence string. We find neither active learning method tested to be better than random choice. The meta-learning method Reptile was found to improve the average accuracy across data sets. Combining meta-learning with active learning offers inconsistent benefits.
A new theory for ionic liquids—the Interstice Model

This paper reports measurements of the surface tension of ionic liquid EMISE (1-ethyl-3-methylimidazolium ethyl sulfate) using the forced bubble method at 278.15 to 323.15 K and densities of EMISE using a Westphal balance at 278.15 to 338.15 K. At the same time, a new theoretical model, the interstice model, is put forward. Applying the model, an expression of the average volume of the interstices, v, was obtained. The calculated volume fraction of the total interstices is 0.12 for ionic liquid EMISE and is in good agreement with that of the majority of materials which exhibit a 10∼15% volume expansion in transition from the solid to liquid state. The value of the thermal expansion coefficient calculated from the model is 5.24 × 10−4 K−1 and is in good agreement with the experimental value 5.37 × 10−4 K−1 at 298.15 K.
23‐Methyl‐3α, 7β‐dihydroxy‐5β‐cholan‐24‐oic acid: Dose‐response study of biliary secretion in rat

A side chain derivative of ursodeoxycholic acid, 23‐methylursodeoxycholic acid, was synthesized and the effect of i.v. infusion of the acid at different doses (0.75, 1.5, 3.0 and 6.0 μmoles per min per kg body weight over 1 hr) on bile flow, on its hepatic biotransformations and on biliary lipid secretion has been studied in bile fistula rats. The results were compared with those of ursodeoxycholic and cholic acid administered under similar conditions. 23‐Methylursodeoxycholic acid is poorly secreted into bile and poorly taurine and glycine conjugated, at all infusion doses.
A novel approach for negative ion analysis using 160 GHz microwave interferometry and laser photodetachment in oxygen cc-rf plasmas

Microwave interferometry at 160.28 GHz with Gaussian beam propagation (beam waist: 5 mm) and laser photodetachment were combined for the analysis of negative atomic oxygen ions in the bulk plasma of an asymmetric capacitively coupled 13.56 MHz discharge (cc-rf). The line-integrated negative oxygen ion density amounts to between 2.5 × 1014 and 1015 m−2 depending on the oxygen pressure and rf power. Furthermore, the measured decay of the detachment signal reveals two modes of rf oxygen plasma characterized by different electronegativities. High electronegativity, α > 2, is associated with a low decay time constant of only a few microseconds, whereas in oxygen plasmas with low electronegativity, α < 1, the relaxation of electron density needs much longer with typical decay time constants of up to about 100 µs. The transition between the two modes shows a step-like characteristic and was observed at a specific rf power depending on the oxygen pressure. In the case of high electronegativity the electron density relaxation can be described by a simple 0D-attachment–detachment model, taking into consideration a constant density for positive ions and neutral oxygen species. Using the appropriate rate coefficients from the literature and the experimentally determined effective rate coefficients of first order kinetics, the evaluation of the attachment and detachment rates indicates the significant role of O2(a 1Δg) in the formation and loss of negative atomic oxygen ions.
Diffusion in Condensed Matter: Methods, Materials, Models

This comprehensive, handbook style survey of diffusion in condensed matter gives detailed insight in diffusion as the process of particle transport due to stochastic movement which is understood and presented as a phenomenon of crucial relevance for a large variety of processes and materials. In this book all aspects of theoretical fundamentals, experimental techniques, highlights of current developments and results for solids, liquids and interfaces are presented.
High performance polydimethylsiloxane pervaporative membranes with hyperbranched polysiloxane as a crosslinker for separation of n-butanol from water

Hyperbranched polysiloxane (HPSiO) was successfully synthesized by a three-step process. The result of 29Si Nuclear Magnetic Resonance (NMR) measurement indicates that the degree of branching (DB) of HPSiO is 0.73. Then, novel polysiloxane membranes, HPSiO-c-PDMS, were prepared by the cross-linking reaction between HPSiO and α,ω-dihydroxypolydimethylsiloxane (H-PDMS) with different molecular weights. HPSiO-c-PDMS membranes were first used as membrane materials for recovering n-butanol from an aqueous solution by pervaporation (PV). The HPSiO-c-PDMS membranes demonstrated high n-butanol/water selectivity as well as high permeability. As the molecular weight of H-PDMS increased, the selectivity increased and the n-butanol permeability of HPSiO-c-PDMS-2 (with moderate H-PDMS molecular weight) membrane showed the highest value. The effects of temperature and feed concentration on the PV performances were also investigated. The PV performance, n-butanol permeability and n-butanol/water selectivity of the HPSiO-c-PDMS-2 membrane, reached 4.3 × 105 Barrer and 8.75, respectively, with a feed concentration of 1.0 wt% at 30 °C.
Some aspects of the theory of comminuted meat adhesion

Summary An apparatus has been designed and built to study adhesive properties of plastic/viscous meat products. It allows for change of geometrical, kinematic and dynamic characteristics within a broad range. A procedure for studying adhesion has been developed. Using a model, theoretical relationships to determine adhesion have been derived, which relate comminuted sausage meat thickness between the plates to the speed of external force application. Tests showed a good agreement between theoretical and experimental data. On the basis of the theoretical relationships, the effect of preliminary contact time, material and plate area on sausage meat adhesion has been experimentally studied. Invariant characteristics of the meat have been found, such as the rate of decrease of contact area and surface tension coefficient; the order of the adhesive activities of various materials towards sausage meat has been determined.
An ADE-FDTD Formulation for the Study of Liquid-Crystal Components in the Terahertz Spectrum

An anisotropic auxiliary differential equation finite-difference time-domain formulation is presented in detail for the time-domain study of nematic liquid crystal devices in the terahertz spectrum. The termination of the computation domain is achieved by employing a properly designed convolution perfectly matched layer. The material dispersion and dichroism of the LC complex permittivities is modeled via a modified Lorentzian function that is demonstrated to provide an accurate description for a series of state-of-the-art materials used in LC-THz technology.
Reactive molecular dynamics force field for the dissociation of light hydrocarbons on Ni(111)

The dissociation of small hydrocarbon molecules on Ni(111) surfaces is investigated using the Materials Studio® density functional theory code DMol3. The energetic barriers for these dissociations were obtained via linear/quadratic synchronous transit analysis. This kinetics information comprises a first principles database for hydrocarbon surface chemistry. The set was used to fit a new reactive molecular dynamics force field which was subsequently applied to consider the rate of finite temperature methane dissociation on Ni(111). In addition, the force field was used to estimate the degree of its transferability to hydrocarbons that are distinct from but structurally similar to those used to generate it.
Environmental Isotopes in Biodegradation and Bioremediation

Isotope Fundamentals Fundamentals of Environmental Isotopes and Their Use in Biodegradation, P. Hohener and C.M. Aelion Analysis of Stable Isotopes, D. Hunkeler and S. Bernasconi Principles and Mechanisms of Isotope Fractionation, D. Hunkeler and M. Elsner Isotope Fractionation During Transformation Processes, D. Hunkeler and B. Morasch Isotopes and Microbial Processes Isotopes and Aerobic Degradation, C.M. Aelion and S.A. Mancini Isotopes and Methane Cycling, E.R. C. Hornibrook and R. Aravena Isotopes and Processes in the Nitrogen and Sulfur Cycles, R. Aravena and B. Mayer Isotopes in Field Applications Investigating the Origin and Fate of Organic Contaminants in Groundwater using Stable Isotope Analysis, D. Hunkeler and R. Aravena Stable Isotope Fractionation of Gases and Contaminant Vapors in the Unsaturated Zone, P. Hohener, D. Bouchard, and D. Hunkeler Isotope Emerging Areas Isotopic Labeling in Environmental and Biodegradation Studies, C.M. Aelion and R.S. Norman Combined Use of Radiocarbon and Stable Carbon Isotopes in Environmental and Degradation Studies, C.M. Aelion Nontraditional Stable Isotopes in Environmental Sciences, C.S. Romanek, B. Beard, A.D. Anbar, and C.F. T. Andrus Index
On the influence of “non‐Redfield” dissolved organic nutrient dynamics on the spatial distribution of N2 fixation and the size of the marine fixed nitrogen inventory

Dissolved organic nitrogen (DON) and phosphorus (DOP) represent the most abundant form of their respective nutrient pool in the surface layer of the oligotrophic oceans and play an important role in nutrient cycling and productivity. Since DOP is generally more labile than DON, it provides additional P that may stimulate growth of nitrogen‐fixing diazotrophs that supply fixed nitrogen to balance denitrification in the ocean. In this study, we introduce semirecalcitrant components of DON and DOP as state variables in an existing global ocean‐atmosphere‐sea ice‐biogeochemistry model of intermediate complexity to assess their impact on the spatial distribution of nitrogen fixation and the size of the marine fixed nitrogen inventory. Large‐scale surface data sets of global DON and Atlantic Ocean DOP are used to constrain the model. Our simulations suggest that both preferential DOP remineralization and phytoplankton DOP uptake are important “non‐Redfield” processes (i.e., deviate from molar N:P = 16) that need to be accounted for to explain the observed patterns of DOP. Additional non‐Redfield DOP sensitivity experiments testing dissolved organic matter (DOM) production rate uncertainties that best reproduce the observed spatial patterns of DON and DOP stimulate additional nitrogen fixation that increases the size of the global marine fixed nitrogen inventory by 4.7 ± 1.7% compared to the simulation assuming Redfield DOM stoichiometry that underestimates the observed nitrogen inventory. The extra 8 Tg yr−1 of nitrogen fixation stimulated in the Atlantic Ocean is mainly responsible for this increase due to its large spatial separation from water column denitrification, which buffers any potential nitrogen surplus in the Pacific Ocean. Our study suggests that the marine fixed nitrogen budget is sensitive to non‐Redfield DOP dynamics because access to the relatively labile DOP pool expands the ecological niche for nitrogen‐fixing diazotrophs.
Comparison of the mineral composition of twelve standard nutrient solutions

Abstract In the past, a large number of standard nutrient solutions has been devised. To investigate if there is an essential difference between these standard solutions, the mineral composition of 12 standard nutrient solutions formulated between 1865 and 1994 are compared with each other. Half of these standard solutions contain ammonium (NH4 +) in a millimolar range. The effect of elemental speciation of the micronutrients in the 12 standard solutions on bioavailability is compared. The macronutrient composition is represented in trilinear coordinates, making a clear comparison of the proportions of both the cations and the anions possible. Also the pH and the total amount of ions present are compared.
Solvent-free ring opening polymerization of ε-caprolactone and electrical properties of polycaprolactone blended BiFeO3 nanocomposites

A novel two-phase polymer nanocomposite comprising polycaprolactone (PCL) and nanocrystalline multiferroic BiFeO3 (BFO NPs) has been fabricated by a simple casting technique. We have developed a new Schiff base ligand–Ti(IV) catalyst based on tridentate ONO chiral amino alcohol, which has been derived from salicylaldehyde. This catalyst plays a vital role in the ring opening polymerization (ROP) of cyclic esters such as e-caprolactone (e-CL). Nanocomposites consisting of multiferroic BFO NPs and insulating PCL have been prepared. It was found that the prepared nanocomposites PCL/BFO/1 wt% and PCL/BFO/3 wt% exhibit ferroelectric properties and reduced leakage of current density. Dielectric data were analyzed using the complex permittivity and complex electric modulus for the nanocomposites at room temperature. An improved AC conductivity for the PCL/BFO nanocomposites was observed compared to the pure PCL and BFO samples.
Water dispersible iron oxide nanoparticles coated with covalently linked chitosan

Magnetic nanoparticles consisting of iron oxide cores modified with covalently linked chitosan oligosaccharide (CSO) that are colloidally stable in water and buffers were obtained. Primary oleic acid coated nanoparticles were synthesized through the thermal decomposition method and the surface ligand exchanged to a carboxylic acid silane. Amide linkage between the chitosan and magnetic nanoparticles was obtained through carbodiimide activation, under conditions which promoted particle stability and chitosan solubility. Magnetic measurements indicate that the particles are superparamagnetic. Measurements of hydrodynamic diameter and zeta potential, coupled with TEM measurements, indicated that CSO coated nanoparticles consist of single primary particles coated with a chitosan corona. These nanoparticles are stable in water for a wide range of pH, and in commonly used biological buffers, such as phosphate buffered saline (PBS), Hank's balanced salt solution (HBSS), and Dulbecco's modified eagle's medium (DMEM) with fetal bovine serum (FBS).
Adsorption Performance and Mechanism in Binding of Azo Dye by Raw Bentonite

The adsorption behavior of methyl orange (MO) from aqueous solution onto raw bentonite (RB) sample was investigated as a function of parameters such as pH, inorganic anion, contact time, and temperature. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. Langmuir adsorption capacity was found to be 34.34 mg/g at pH 4.0. The pseudo-first-order, pseudo-second-order kinetic, and the intra-particle diffusion models were used to describe the kinetic data. The values of the energy (E a ), enthalpy (ΔH ≠ ), and entropy of activation (ΔS ≠ ) were calculated as 38.62 kJ/mol, 36.04 kJ/mol, and ―150.05 J/mol K, respectively, at pH 4.0.