Miracle-dz/UniFAR-FTUs huggingface dataset:
Sorption and Desorption of Atrazine by Sludge-Amended Soil: Dissolved Organic Matter Effects

Addition of insoluble and soluble organic C to soil through management practices, such as sewage sludge (SS) application, may greatly alter pesticide sorption-desorption in soil. Batch equilibrium techniques were used to determine the effects of four sewage sludges (liquid-SS, solid-SS, limed-SS, and composted-SS) and their water dissolved organic matter (DOM), on the sorption-desorption of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) by a silt loam soil. Atrazine sorption on the sludges increased in the order: limed-SS < liquid-SS < solid-SS < composted-SS. Sludge addition to soil increased atrazine sorption in the same order, although the effectiveness of the mixtures to sorb atrazine was lower than expected from the sorption capacity of the isolated soil and sludges. The effects of the DOM extracted from the different sludges on atrazine sorption varied with sewage sludge. For liquid-, solid-, and limed-SS, DOM reduced atrazine sorption on soil. A low association between these DOMs and atrazine was measured in solution by dialysis technique, and indicated that processes at the soil/solution interface may have contributed to reduce atrazine sorption. In contrast, enhanced atrazine sorption in the presence of DOM extracted from composted-SS indicated atrazine was bound by DOM associated with the soil. Atrazine desorption from soil increased in the presence of DOM from all four sludges; however, DOMs had little effect on atrazine desorption from sludge and from sludge-amended soil. Interactions of soil surfaces with organic amendments and their DOM are shown in this work as a major process determining atrazine sorption-desorption in amended soil.
The relationship between aquatic toxicity QSARs and bioconcentration for some organic chemicals

Aquatic toxicity testing is conducted largely by means of a single experimental protocol-the concentration-response toxicity test. This procedure has a number of well-known limitations resulting from the fact that the relationship between the waterborne toxicant concentration and the actual body toxicant concentration which is producing the observed biological response is unknown. Hence quantifying the influence of chemical potency, physical, chemical and biological factors and elapsed time on the outcome of toxicity tests is difficult. Interpretation, and even more significantly, predictability may be severely restricted. Using, and further quantifying, the links between octanol-water partition coefficients, bioconcentration and acute and chronic toxicity quantitative structure-activity relationships (QSARs) for narcotic organic chemicals has allowed the following conclusions to be made: (1) Establishing internal toxicant concentrations related to acute and chronic effects, as estimated in this paper, will allow the toxicological significance of body burdens of certain organic chemicals, both singly and in certain mixtures, to be determined. (2) Chemical potency, as determined in the exposed organism, appears to be essentially constant for each of the biological responses and organic chemical groups examined. (3) The acute and chronic QSARs discussed herein are all parallel, each having a slope of unity. (4) It appears, as a first approximation, that a one-compartment, first-order kinetics model could provide a quantitative means of studying aquatic toxicity test results, both retrospectively and prospectively. (5) Bioconcentration and toxicity kinetics appear to be similar, but the internal toxicant concentration endpoint is different, fixed for toxicity and variable for bioconcentration.
Functionalized poly(vinyl alcohol) based nanofibers for the removal of arsenic from water

Arsenic is a potent contaminant in waterways across the world. In this investigation, Fe3+ ion immobilized poly(vinyl alcohol) (PVA) nanofibers were used for the removal of arsenic (As) from water. Nanofiber mats were prepared from a PVA/Fe3+ mixture using an electrospinning technique and cross-linked in a desiccator saturated with ammonia vapour. The fibers showed a smooth surface morphology and were 600–800 nm in diameter. An increase in the glass transition temperature along with a lowering of the melting peak enthalpy with an increase in the concentration of Fe3+ ions was observed. The nanofibers extracted As(III) and As(V) compounds from spiked aqueous solutions. The maximum capacity of the nanofibers for arsenic removal was found to be 67 mg g−1 for As(III) and 36 mg g−1 for As(V). The effect of pH on the adsorption behavior was compared for both acidic and basic conditions. The effect of coexisting anions such as silicate ions on the adsorption behavior showed significant interference, whereas humic acid had no significant effect on the adsorption behavior. The FTIR and XPS spectroscopic analyses demonstrated that arsenic ions were adsorbed on the sorbent surface. Hence, these modified PVA nanofibers are efficient for removing arsenic from water and may be used for water purification.
Materials and growth issues for high-performance nonpolar and semipolar light-emitting devices

Growth of InGaN/GaN light-emitting devices on nonpolar or semipolar planes offers a viable approach to reducing or eliminating the issues associated with polarization-related electric fields present in c-plane III-nitride heterostructures. Although progress in device performance has been rapid since the introduction of high-quality free-standing nonpolar and semipolar GaN substrates, a full appreciation of the materials challenges unique to nonpolar and semipolar III-nitride semiconductors has been slower to emerge. Only recently have researchers begun to understand issues such as the origins of the pyramidal hillocks typically observed on nominally on-axis m-plane GaN films, the effects of m-plane substrate misorientation on surface morphology and device performance, the mechanics of anisotropic cracking in tensile strained m-plane AlGaN films, the formation of basal-plane stacking faults in long-wavelength m-plane InGaN quantum wells, and the mechanisms for stress relaxation in semipolar AlGaN and InGaN films. In this paper, we review the materials and growth issues unique to high-performance nonpolar and semipolar light-emitting devices grown on high-quality free-standing GaN substrates and provide an outlook for the opportunities and challenges that lie ahead.
Synthesis, characterization, and permeability evaluation of hybrid organic–inorganic films

The preparation and characterization of hybrid organic–inorganic films based on poly(dimethylsiloxane), PDMS, crosslinked with nanoclusters obtained from pentaerythrithol triacrylate (PETA) and 2-aminoethyl-3-aminopropyltrimethoxysilane (AS), are reported. The introduction of silica nanoclusters, obtained from tetraethoxysilane as an additional crosslinker, improved the mechanical stability of the films and also produced a noticeable decrease in the solvent sorption and in the distance between the nodes of the polymeric networks. The performance of these films as membranes for gas separation processes was similar to those reported for commercial PDMS, although they presented polar organic PETA/AS crosslinker nuclei. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4281–4292, 2004
DRYING KINETICS OF CORIANDER (Coriandrum sativum) LEAF AND STEM CINÉTICAS DE SECADO DE HOJA Y TALLO DE CILANTRO (Coriandrum sativum)

Abstract The drying kinetics of coriander leaves and stems, with or without blanching, was studied at several temperatures (50, 60, 70, and 80°C) at constant air velocity (1.5 m s−1) in a fixed-bed dryer. Three drying models, Henderson and Pabis, Midilli et al., and the Logarithmic, were fitted to the experimental data. According to the results obtained, it was verified that the increase in the temperature of drying air, increases the drying rate of the coriander leaf and stem. Blanching used as a pre-treatment favors the increase in the drying rate of the stem. The Midilli et al. drying model was found to satisfactorily describe the air-drying curves of coriander leaves and stems. Resumen La cinética del secado de las hojas y tallos de cilantro, con o sin escaldado, se estudió a diferentes temperaturas (50, 60, 70 y 80°C) con velocidad constante del aire (1,5 m s−1) en un secador de lecho fijo. Tres modelos matemáticos: Pabis y Henderson, Midilli et al., y el logarítmico, se ajustaron a los datos experimentales. De acuerdo a los resultados obtenidos, se comprobó que el aumento de la temperatura del aire de secado, aumentó la velocidad de secado de la hoja y tallo de cilantro. El escaldado utilizado como pre-tratamiento, favorece el aumento en la velocidad de secado del tallo. El modelo matemático de Midilli et al. presentó mejor ajuste para los datos experimetales. Palabras clave: Pretratamiento, Coriandrum sativum, escaldado, deshidratacíon
Reduction of palladium (II) in aqueous solution: stabilization and reactions of an intermediate cluster and palladium colloid formation

In the γ-radiolytic reduction of Pd(NH 3 ) 4 Cl 2 in the presence of poly(ethyleneimine), an intermediate cluster is stabilized by the polymer. Pulse radiolysis experiments show that it is slowly formed in the 0.01-1-s range after the primary reduction of Pd(II) to Pd(I) by hydrated electrons and organic radicals has occurred in the 0.1-100-μs range. A photochemical method for the preparation of the cluster is also described. The cluster absorbs at 308 and 400 nm and decays within a few days to yield colloidal palladium metal
Optical properties of embedded metal nanoparticles at low temperatures

Metal nanoparticles (gold, silver, copper) that are embedded in an insulating organic host material exhibit optical plasma resonance absorption in the visible and near-infrared region. The spectral position, the half width and the intensity of the plasma resonance absorption all depend on the particle size, the particle shape, and the optical behavior of the cluster and the host material. The optical extinction of various gold, silver or copper particle assemblies embedded in plasma polymer or gelatin was measured at 4.2 K and 1.2 K as well as at room temperature. The packing density of several samples was high enough to resolve a reversible increase of the plasma resonance absorption intensity towards lower temperatures. Additionally, at larger silver particles nm a significant blue shift of the plasma resonance absorption was measured. Particle size and shape distribution were determined by transmission electron microscopy (TEM). For the first time, simultaneous measurements of the electrical and optical properties at one and the same particle assembly were performed at low temperatures. Contrary to the increasing optical extinction, the d.c. conductivity decreased to two orders of magnitude. At silver particles embedded in a plasma polymer made from thiophene a significant photocurrent was measured.
Astrophysical Icy Surface Simulation under Energetic Particles and Radiation Field in Formic Acid

In this work, the fragmentation, survival, and chemical reactions of formic acid (HCOOH) molecules condensed at 56 K are analyzed using plasma desorption mass spectrometry (PDMS) and photon-stimulated ion desorption (PSID) in an effort to simulate the effects of energetic charged particles (e.g., cosmic rays) and radiation fields on interstellar/cometary ices. The measurements were taken at the Brazilian Synchrotron Light Laboratory (LNLS), employing soft X-ray photons (535.1 eV) and energetic ions (∼65 MeV) obtained as 252 Cf fission fragments. Mass spectra of positive and negative desorbed ions were obtained using a time-of-flight (TOF) spectrometer, providing information on the fragmentation pattern and abundance of the ionic species released from the icy surface. In both techniques, the major contribution to the released/desorbed ions were positively charged fragments. The production of several series of clusters, some of them with mass/charge ratios of up to 500 u/e, was observed in the PDMS spectra. Comparison between the employed techniques (photon and ion impacts) indicates that the interaction of energetic ions with formic acid ice produces a greater variety of ions than soft X-ray photon impact. This suggests that cosmic rays and high-energy solar wind particles, despite its reduced flux compared to other lower-energy particles, might play an important role in the synthesis of prebiotic molecules.
Propriétés spectroscopiques et effet laser d'un verre tellurite et d'un verre phosphate fortement dopés en néodyme

On presente quelques proprietes spectroscopiques, de verres dopes, importantes pour la conception de mini-lasers telles que : forces d'oscillateur, section. efficace laser, duree de vie radiative et rendement quantique en fonction de la concentration. Deux verres, un tellurite de lithium et un phosphate de cadmium potassium assez fortement dopes en neodyme (concentration respective 0,91 et 0,73 x 1021 at. Nd3+ cm-3) sont consideres. On verifie que ces verres ont une grande section efficace laser, soit σ1 ∼ 0,45 x 10-20 cm2, moins de deux fois plus faible que celle d'un monocristal d'ultraphosphate de neodyme, et que les processus de desexcitation non radiatifs du niveau 4F 3/2 en fonction de la concentration sont relativement faibles ce qui en fait des materiaux comparables aux cristaux stœchiometriques recherches actuellement pour la mise au point des systemes mini-lasers. Nous confirmons les conclusions que l'on peut tirer des resultats spectroscopiques en montrant que ces verres peuvent manifester l'effet laser en continu dans des structures optiques compactes et lorsqu'ils sont pompes longitudinalement a la longueur d'onde de 5 145 A. Nous trouvons en particulier que le verre tellurite a un seuil laser de 3,12 mV absorbes par % de pertes.
Efficient identification of hydrophobic MOFs: application in the capture of toxic industrial chemicals

Water is an ever-present component in the air, and competitive adsorption of water is a major challenge in many applications of adsorbents, including capture of toxic industrial chemicals (TICs) from the atmosphere. For metal–organic framework (MOF) adsorbents, the presence of water often leads to major material instabilities that could limit their practical performance. MOFs displaying hydrophobic behavior might be useful in overcoming these problems. In this work, we present a new computational strategy to quickly identify hydrophobic MOFs based on their water Henry's constants. Starting with a database of 137 953 hypothetical MOFs, we identified 45 975 structures as hydrophobic based on their simulated water Henry's constants. Using grand canonical Monte Carlo simulations, we further analyzed 2777 of these hydrophobic materials whose linkers did not contain chemical functionalization. The results show insignificant water uptake in the identified MOFs, confirming their hydrophobic nature. The capability of the hydrophobic MOFs was assessed for ammonia capture under humid conditions, and analysis of the data generated from this high-throughput computational screening revealed the role of the textural properties and surface chemistry on the removal of toxic compounds. The results suggest that if materials are too hydrophilic, they adsorb too much water and show little or no selectivity towards TICs. On the other hand, if they are too hydrophobic, they adsorb too little ammonia.
Characterization of plant growth promotion and disease control trends of rhizobacteria isolated from Umorok (Capsicum chinense)

The aim of the study is to identify and characterize the rhizosphere bacteria of King Chili locally known as Umorok plant (Capsicum chinense) and evaluates their plant growth promotion and defense from pathogens. A total of 300 rhizobacteria were isolated from three different growth stages of king chili viz.; juvenile, flowering and fruiting growth stages and characterized to establish the beneficial role. Nevertheless, the isolated microorganisms were evaluated for their in-vitro plant growth promotion potential by performing biochemical tests and pathogen antagonistic activities by dual culture methods. Out of the total isolates, 10 potential rhizobacteria were selected for pot culture experiment based on their multiple Plant Growth Promoting Rhizobacteria (PGPR) and biocontrol activity. Since these inoculants exhibited multiple trait benefits to the host plant, they can be adapted as potential bio-inoculant consortia for plant health improvement and disease control to increase Umorok productivity.
12.88 W/mm GaN High Electron Mobility Transistor on Silicon Substrate for High Voltage Operation

We have demonstrated the highest RF output power density of 12.88 W/mm, to our knowledge, at 2.14 GHz in GaN high electron mobility transistor on silicon (Si) substrate at high voltage operation. This highest record was achieved by reducing the parasitic loss at the conductive interface layer between the epitaxial structure and the Si substrate, and thinning the Si substrate thickness. The parasitic loss evaluation by a capacitance–voltage method proved to be effective since the epitaxial wafer selection is possible without fabricating RF devices. Si substrate as thin as 60 µm results in good thermal resistance and contributes to the large RF output power density.
Effects of Surface Defects, Polycrystallinity, and Nanostructure of Self-Assembled Monolayers for Octadecanethiol Adsorbed onto Au on Wetting and Its Surface Energetic Interpretation

We report low-rate dynamic contact angle data of various liquids on self-assembled monolayers (SAMs) of octadecanethiol on annealed and nonannealed gold. It was found that interpretation of solid surface tensions using contact angle data on less well-prepared polycrystalline nonannealed gold surfaces can be misleading. Our findings were supported by reflectance infrared spectra and atomic force microscopy data that the surface nanostructure, defects, and polycrystallinity can be important factors for a systematic study of wettability on SAMs in terms of surface energetics. We found that the contact angle and adhesion patterns of various liquids on SAMs of octadecanethiol adsorbed onto annealed gold substrates are consistent with recent experimental data for the relatively thick polymer-coated surfaces. The variation of surface structure in terms of surface energetics can be estimated only when a fundamental understanding of contact angles and surface tensions is known. We estimated an increase in the soli.
Chemistry And Applications Of Inorganic-Organic Polymers (Organically Modified Silicates)

The conbination of inorganic polymeric networks with organic components leads ot inorganic-organic polymers. A convenient method for the introduction of organic radials into an inorganic backbone is the use of aorganosubstituted silico esters in a polycondensation process. This leads to ≡Si-O-Si≡ network containing materials, so-called organically modified silicates (ORMOSILs). For the synthesis of the inorganic backbone, in opposition to the high temperature preparation of non-metallic inorganic materials like ceramics, "Soft chemistry" methods have to be applied in order to preserve organic groupings to be incorporated. Therefore, the sol-gel process is a suitable technique [1-5]. A review over basic synthesis principles and chemical methods, their effect on special material properties and the application potential will be given.
Electrostatic forces between sharp tips and metallic and dielectric samples

A detailed analysis of electrostatic interactions between a dc-biased tip and a metallic or insulating sample is presented. By using a simple method to calculate capacitances and forces, tip shape effects on the force versus tip-sample distance curves are dicussed in detail. For metallic samples the force law, except for a constant background, only depends on the tip radius of curvature. In contrast, for dielectric samples the forces depend on the overall geometry of the tip. Interestingly, we found that the contact (adhesion) force does not depend on the tip size and is bound by a simple expression which only depends on the applied bias and the sample dielectric constant.
Rapid Deswelling Response of Poly(N-isopropylacrylamide) Hydrogels by the Formation of Water Release Channels Using Poly(ethylene oxide) Graft Chains

Poly(ethylene oxide) (PEO) chains are introduced as graft chains maintaining freely mobile ends in thermo-responsive cross-linked poly(N-isopropylacrylamide) (PIPAAm) hydrogels by copolymerization of IPAAm with α-acryloyl-ω-methoxy-PEO. The deswelling response on raising the temperature of this gel above the gel phase transition temperature (TP) takes place within 10 min, whereas a conventionally cross-linked PIPAAm gel of the same dimensions requires 1 month for deswelling. This difference is due to the formation of water release channels within the skin layer by the hydrophilic PEO graft chains. The rapid deswelling of the grafted gel is compared with the deswelling changes of random copolymer gels composed of IPAAm and hydrophilic acrylic acid (AAc), which also accelerates gel deswelling. Deswelling is fastest in copolymers containing 1.3 wt % AAc and in grafted gels containing 13 wt % PEO. These results were interpreted as reflecting the gel structure.
Corrosion Mechanisms and Products of Copper in Aqueous Solutions at Various pH Values

Abstract The corrosion behavior of copper in aqueous solutions of different pH values was investigated using electrochemical and surface analysis methods. It was shown that the corrosion mechanism changed with pH and was associated with morphology of the surf ace films formed. In solution of pH 3, the copper surface was covered with porous corrosion products of cuprous oxide (Cu2O). Corrosion was controlled predominately by diffusion in solution. In solutions of pH 4 to pH 5, formation of cubic Cu2O on the copper surface provided a diffusion barrier to copper dissolution. The anodic process was controlled by a mixed diffusion of copper ions in oxide films and in solution. In solutions of pH 6 to pH 9, the oxide films (Cu2O) became more protective. Diffusion in the oxide films became a rate-determining step of anodic dissolution. In pH 10 solution, a thin, compact Cu2O film formed, and spontaneous passivation was observed. At pH 12 and pH 13, analysis by x-ray photoelectron spectroscopy (XPS) and scanning .
Molecular Orientation Dependent Energy Level Alignment at Organic−Organic Heterojunction Interfaces

Molecular orientation dependent energy level alignments at organic−organic heterojunction (OOH) interfaces have been investigated with synchrotron based high-resolution photoemission spectroscopy and near-edge X-ray absorption fine structure (NEXAFS) measurements. Model systems of the lying-down 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) films on both standing-up and lying-down copper hexadecafluorophthalocyanine (F16CuPc) and copper(II) phthalocyanine (CuPc) thin films have been used to illustrate the molecular orientation dependent interface properties. The formation of different interface dipoles at the heterojunction interfaces is strongly influenced by the orientation dependent ionization potentials of the underlying F16CuPc or CuPc thin films. This is attributed to the intrinsic surface dipoles induced in the standing-up F16CuPc (CuPc) film due to the polar intermolecular C−F (C−H) bonds formed at the interface. In situ NEXAFS measurements reveal that the room-temperature deposition of PT.
Nitrogen‐related deep electron traps in float zone silicon

Two deep levels (electron traps) associated with nitrogen were identified in high resistivity float zone silicon employing deep level transient spectroscopy. The levels are formed during annealing at high temperatures (≥900 °C). They exhibit activation energies of Ec −0.58 eV and Ec −0.5 eV. The electron capture cross section for the 0.58 eV level is about 5×10−14 cm2. The levels appear to be associated with complexes rather than isolated nitrogen atoms.