Miracle-dz/UniFAR-FTUs huggingface dataset:
Modelling of the homogeneous barrier discharge in helium at atmospheric pressure

Numerical calculations of spatio-temporal characteristics of the homogeneous barrier discharge in helium are performed by means of a one-dimensional fluid model. The influence of the elementary processes on the discharge behaviour is studied by variation of the corresponding rate constants. The simulation and the analytical interpretation are carried out for two basic modes of the homogeneous barrier discharge, i.e. the Townsend and glow modes. The Townsend discharge is characterized by the absence of quasineutral plasma; several current peaks may occur during the half-cycle. The oscillations of the current are caused by a lag between the ion production nearby the anode and the subsequent ion–electron emission on the cathode. The specificity of the glow discharge is the development of a cathode region and a positive column during the breakdown, as well as the presence of quasineutral plasma in subsequent phases. The positive column occurs because the shielding of the external field by the plasma is not instantaneous. The dependence of the discharge behaviour on the external parameters, such as the amplitude and frequency of the applied voltage, discharge gap width, and thickness of dielectric barriers, is analysed. The mode of the discharge is governed mostly by the gap width and barrier thickness and depends weakly on the amplitude and frequency of the applied voltage. As the barriers are thin and the discharge gap is sufficiently wide, the glow mode occurs; otherwise, the discharge is Townsend.
Effect of Pt Loading Order on Photocatalytic Activity of Pt/TiO2 Nanofiber in Generation of H2 from Neat Ethanol

TiO2 nanofibers that are loaded with 1 wt % Pt metal that is introduced at different stages of the wet impregnation procedure have very different photocatalytic activities. Two photocatalysts prepared using different procedures were denoted as PtHTN and PtB catalysts. The former was prepared by impregnating hydrogen trititanate nanofibers (H2Ti3O7, abbreviated as HTN) directly with H2PtCl6, before calcining between 573 and 873 K and then reducing at 423 K in flowing hydrogen. The latter was prepared by initially calcining HTN nanofiber between 573 and 873 K to yield TiO2 nanofiber, and then impregnating this TiO2 support with H2PtCl6; the support was then calcined and reduced as PtHTN to produce PtB catalysts. Although most of their physical properties such as surface area, pore volume, crystalline phase composition and crystallinity, capability to absorb UV light, and band gap energy are quite similar, the optimized H2 yield over PtB catalyst in the photocatalytic dehydrogenation of neat ethanol was 1.86.
Modeling of H+ and Cu2+ Adsorption on Calcium-Montmorillonite

AbstractThe interaction of H+- and Cu2+-ions with Ca-montmorillonite was investigated in 0.1 mol/dm3 solutions of Ca(CIO4)2 at 298.2 K by Potentiometrie titrations using both glass electrodes (for H+) and ion specific electrodes (for Cu2+ ). The experimental data were interpreted on the basis of the surface complexation model. The calculations were performed with the least-squares program FITEQL (Westall, 1982) using the constant capacitance approximation. The best fit was obtained with a set of equilibria of the general form $$\begin{array}{c}pH^{+}+qCu^{2+}+\equiv{SOH}\Leftrightarrow(H^{+})_p(Cu^{2+})_q(\equiv{SOH})^{(p+2q)+}\\ \beta_{p,q(int)}^s=\frac{\text[H_pCu_q(\equiv{SOH})^{(p+2q)}]}{\text[H^+]^{p}[Cu^{2+}]^q[\equiv{SOH}]}\end{array}$$pH++qCu2++≡SOH⇔(H+)p(Cu2+)q(≡SOH)(p+2q)+βp,q(int)s=[HpCuq(≡SOH)(p+2q)][H+]p[Cu2+]q[≡SOH] and the constants logβ1,0(int)S = 8.16 (± 0.04), logβ-1,0(int)S = −8.71 (± 0.08), logβ0,1(int)S = 5.87 (± 0.06), logβ−1,1(int)S = −0.57 (± 0.12), logβ−2,1(int)S = −6.76 (± 0.02). An appropriate modeling of the H+ adsorption data requires the introduction of a second surface group ≡ TOH with the acidity constant $$\equiv{TOH}-H^+\Leftrightarrow{\equiv}{TO}^-log\beta_{-1,0(int)}^S=-5.77(\pm0.07). $$≡TOH−H+⇔≡TO−logβ−1,0(int)S=−5.77(±0.07). In addition, the ion exchange equilibria Ca2+ − Cu2+ and Ca2+ − H+ had to be taken into account. Arguments are presented to identify the groups ≡ SOH and ≡ TOH as surface aluminol groups =Al(OH)(H2O) and surface silanol groups ≡ Si-OH, respectively.
Defect-permeation correlation for ultrathin transparent barrier coatings on polymers

We begin this article by presenting a model for gas permeation through defects in barrier coatings, which is based on a very simple geometrical approach. This model allows us to evaluate permeation through a single- or through multiple circular defects in the coating, and also in special cases of size distributions and noncircular geometries. The model agrees well with published results based on complex computer simulations, and it has proven very useful in the analysis of our permeation measurements for barrier-coated plastic films. We then present correlations between measured O2 transmission rate (OTR) values and the number densities and size distributions of defects in SiO2 and SiN barrier coatings on polyester (PET), results which we compare with published data for aluminized PET. We also show the temperature dependence of OTR and H2O vapor transmission rate for SiO2 and SiN coatings deposited on one and on both sides of PET films. The apparent activation energies evaluated from these measurements su.
The theory of metal - ceramic interfaces

The theory of metal - ceramic interfaces is a collection of approaches which are complementary. They range from thermodynamic modelling based on empirical correlations, through the image model of adhesion, semi-empirical tight-binding calculations, to first-principles calculations based on applying the density functional theory or Hartree - Fock theory. This article reviews the present state of theoretical calculations, with particular reference to electronic structure and adhesion. A section on the thermodynamic background clarifies the concept of work of adhesion which is the goal of many calculations. Cluster models and periodic slabs have been considered, both self-consistent and non-self-consistent. The most sophisticated and complete calculations have been made for metals on MgO and alumina. There a consistent picture of the nature of the bonding has emerged, although there are still significant unexplained discrepancies in numerical values.
Behavior of Phragmites australis (CAV.) Trin. Ex Steud used in phytoremediation of wastewater contaminated by cadmium

AbstractDirect use of green plants to stabilize or reduce contamination in soils, surface water, or ground water has gained increasing popularity in both academic and practical fields. Phytoremediation is a low-cost and friendly technology to the environment, not only for the elimination of heavy metals but also for the various pollutions. This study investigated the effect of cadmium chloride (CdCl2) on chlorophyll and lipids contents and evaluated the activity of guaiacol peroxidase (GPOX) in Phragmites australis aerial and root part. Known as common reed, this plant is widely used for the treatment of wastewater contaminated with heavy metals. The analysis of those selected physiological parameters has allowed understanding cellular behavior in the presence of various concentrations of cadmium. The results showed that low doses of CdCl2 induced a significant increase in total chlorophyll content (A + B) unlike the other two doses, as well it was demonstrated that CdCl2 induced a negative dose-dependent.
EFFECT OF PARTICLE SIZE DISTRIBUTION ON THE CUT POINT BETWEEN FINE AND COARSE AMBIENT MASS FRACTIONS

AbstractA review of recent studies on the size distribution of ambient particles reveals considerable variability, both spatially and temporally, depending on the source of origin, geographical location, meteorological conditions, and various other chemical and physical parameters. However, there is generally a clear separation into fine and coarse modes, with a dividing point between 1.0 and 2.5 μmlm where the mass of the two modes is at a minimum. In the 1970's, the U.S. Environmental Protection Agency (EPA) developed the dichotomous sampler to separate fine and coarse particles and choose a cut point at 2.5 μmlm. However, recent data collected with new samplers, such as the size-fractionating MOUDI impactor, reveal that both aged sulfates and particles associated with aerosol acidity reside in the range below 1.0 μmlm diameter. Indoor combustion aerosols such as cigarette smoke and kerosene heater emissions have also been found to reside in the sub-micrometer range. Before embarking on a new and extens.
Structural characterization of the C2 domains of classical isozymes of protein kinase C and novel protein kinase Cε by using infrared spectroscopy

The amide I regions in the original infrared spectra of PKCα -C2 in the Ca 2+ -free and Ca 2+ -bound states are both consistent with a predominantly β-sheet secondary structure. Spectroscopic studies of the thermal denaturation revealed that for the PKCα-C2 domain alone the secondary structure abruptly changed at 50 ◦ C. While in the presence of Ca 2+ ,t he thermal stability of the protein increased considerably. Phosphatidic acid binding to the PKC α-C2 domain was characterized, and the lipid-protein binding becoming Ca 2+ -independent when 100 mol% phosphatidic acid vesicles was used. The effect of lipid binding on secondary structure and thermal stability was also studied. In addition, the secondary structure of the C2 domain from the novel PKCe was also determined by IR spectroscopy and β-sheet was seen to be the major structural component. Spectroscopic studies of the thermal denaturation in D2O showed a broadening in the amide Iband starting at 45 ◦ C. Phospha- tidic acid containing vesicles were used to characterize the effect of lipid binding on the secondary structure. It was observed through thermal stability experiments that the secondary structure did not change upon lipid binding and the protein stability was very high with no significant changes occurring in the secondary structure after heating.
Diagnostic technique of pine wood nematode disease based on THz spectrum

Pine wood nematode disease, namely pine wilt disease, is caused by the invasion of Bursaphelenchus xylophilus (Bx) into pines. Once susceptible pines are infected by the nematode, the disease develops rapidly, the infected pines cease to exude oleoresin and die quickly. Hence it is called pine cancer. Given the fact that there are still no good methods in diagnosing the disease, here we propose to study the spectroscopic characteristics of pine wood nematode and diseased pine wood in the THz regime in order to look for a rapid spectroscopic discrimination method for the disease. Firstly, we measure the transmittances of a Bx sample, a B. mucronatus (Bm) sample, a healthy Pinus massoniana wood sample and a diseased P. massoniana wood sample by a superconducting heterodyne mixer at 500 GHz. And their characteristics are compared. Secondly, we measure the transmission characteristics of a Bx sample and a Bm sample by terahertz time domain spectroscopy (THz-TDS). The measured time domain spectrums and corresponding frequency domain spectrums are compared to distinguish them from their absorption characteristics. Thirdly, we measure the transmission characteristics of a healthy P. massoniana wood sample and a diseased P. massoniana wood sample by THz TDS and compare their difference in THz absorption spectrum and diffraction dispersive spectrum to confirm the effect of Bx on P. massoniana by the absorption coefficient and refractive index. Some discussions are given for future development of the diagnostic technique of pine wood nematode disease based on THz spectrum.
A comparison of integral equations and density functional theory versus Monte Carlo for hard dumbbells near a hard wall

A comparison of Percus–Yevick–Pynn–Lado model theory and a density functional (DF) theory of nonuniform fluids of nonspherical particles is performed. The DF used is a new generalization of Tarazona’s theory. The conclusion is that DF theory provides a preferable route to describe the system under consideration. Its accuracy can be improved with better approximation for the direct correlation function (DCF) for bulk system.
Analyses of the N.M.R. spectra of pyrrole derivatives: pyrrole-2-carboxylic acid and pyrrole-2-aldehyde

By the N-decoupling technique the spectrum of the N-H proton in pyrrole-2-carboxylic acid and pyrrole-2-aldehyde was clearly unveiled. Using the full spectra including the N-H band, the N.M. R. parameters of the two pyrrole derivatives were determined with a high degree of accuracy by computer simulation. It was demonstrated that two types of long-range coupling exist for the aldehyde proton of pyrrole-2-aldehyde. From partial decoupling experiments by using the third r.f. field the relative signs of all coupling constants were determined to be the same for the two pyrrole derivatives, except for a long-range coupling, J cho-nh , in pyrrole-2-aldehyde. Based on an assumption that the long-range couplings of the aldehyde proton originate from the pi electrons, it was concluded that the absolute signs of all coupling constants among the ring protons of pyrrole-2-aldehyde were positive.
Leaf Volatile Oil Composition of Mandarin (Citrus reticulata) from Nigeria

ABSTRACT A combination of GC and GC/MS was used to characterize the chemical composition of the leaf oil of mandarin (Citrus reticulata) from Nigeria. A total of twenty-two compounds were identified in the oil. The main compounds were found to be γ- terpinene (20.15%), p-cymene (16.29%), linalool (9.55%) and terpinen-4-ol (7.13%).
Separation of Carbon from Fly Ash Using Froth Flotation

The unburned carbon content of fly ash from two different power stations was greatly reduced in two-stage laboratory flotation tests by employing a collector consisting of nonylphenol and either hexadecane or fuel oil together with methyl isobutinol (MIBC) as a frother. The tailings from the first stage were recleaned in the second stage. This method reduced the carbon content of fly ash from an initial level of 25.9% in one case and 16.5% in another case to a final level of 1–2% or less in the tailings while at the same time recovering 95% or more of the carbon in the floated material or concentrate. In most cases from 60 to 75% of the ash was rejected in the tailings. The results support a previous finding that a good collector for oxidized coal is a good collector for unburned carbon in fly ash. Furthermore, the results showed that much less collector was required to achieve a good separation of carbon from fly ash when MIBC was employed in conjunction with the mixed collector.
Formation of Gold and Silver Nanoparticles in Aqueous Solution of Sugar-Persubstituted Poly(amidoamine) Dendrimers

Stable nanosize gold and silver particles are spontaneously formed by reduction of aqueous metal salt solutions in the presence of sugar-persubstituted poly(amidoamine) dendrimers (sugar ball). Two sugar balls consisting of generations 3 and 5 are used. The nanoparticles are characterized by absorption spectroscopy, electron microscopy, and FT-IR spectroscopy. In the formation of silver particles, alkaline solution is required. In the process of reduction, characteristic absorption bands appear for the respective metal particles and the intensities increase with reaction time. The sigmoidal curve of intensity vs the reaction time suggests an autocatalytic reaction. The apparent rate constants for the formation of gold particles increase with the concentration of sugar ball, where the rate constants are greater for generation 3 than for generation 5 at the same weight percent of sugar ball. On the other hand, an opposite trend is observed for the formation of silver particles. The average diameters of gold and silver range between 2 and 6 nm and their size distributions are relatively wide.
Impact of stone content on water movement in water‐repellent sand

Soils are commonly stony, especially in steep upland or heavily degraded sites. The hydrological effect of large stone contents has been previously investigated in wettable but not in water‐repellent soils. For the latter, the focus has instead been on the impact of other soil characteristics (e.g. cracks and macropores) likely to promote water percolation. This paper investigates stone effects on water flow in water‐repellent sand under laboratory conditions. Seventy‐five experiments were performed on a water‐repellent sand mixed with a range of quantities of different‐sized wettable and water‐repellent stones. The time taken for water to pass through each sand–stone mix, the percolated water volumes and numbers of dry and wet stones following each 60‐minute experiment were recorded. At large stone contents (> 55% or > 65% by weight, depending on stone wettability), percolation occurred relatively quickly and in comparatively large quantities. At intermediate stone contents (45–65%) percolation response was variable and at stone contents < 45% for wettable and < 55% for water‐repellent soils no water percolation occurred. We argue that with large stone contents flow pathways develop along sand–stone interfaces and a continuous preferential flow path can form provided there are sufficient stone‐to‐stone connections. The distribution and alignment of the stones, especially at intermediate stone contents, are important for promoting water movement. Water repellency determinations based only on the fine sediment component in stony soils could therefore be misleading as regards determining their hydrological response: the influence of the clastic component must also be considered.
Rates of Nitrate and Perchlorate Removal in a 5‐Year‐Old Wood Particle Reactor Treating Agricultural Drainage

A 5‐year‐old wood particle reactor treating agricultural tile drainage in southern Ontario was monitored for its ongoing ability to treat both nitrate (NO3–) and perchlorate (ClO4–). Prior to sampling undertaken in the fifth year of operation, a highway safety flare containing ClO4– was immersed in the inlet pipe elevating influent ClO4– concentrations to up to 33.7 μg/L. ClO4– removal rates were inhibited in the presence of more than 1 to 2 mg/L NO3–‐N, but increased rapidly to about 60 μg/L/d upon NO3– depletion. Nitrate removal rates, measured subsequently in the sixth and seventh years of operation, varied with temperature in the range of 2 to 16 mg N/L/d, but remained similar to rates measured in the second year. Additionally, no deterioration in the hydraulic conductivity (K) of the coarse core layer (0.5
Phytoaccumulation of Trace Elements by Wetland Plants: I. Duckweed

There has been much interest recently in the use of constructed wetlands for the removal of toxic trace elements from wastewaters. Wetland plants play an important role in the trace elements removal process. It is not known, however, which wetland plant species absorb specific trace elements at the fastest rates. Such knowledge is essential to maximize the efficiency of trace element removal by wetlands. In this study, we investigated the potential of duckweed (Lemna minor L.) to accumulate Cd, Cr, Cu, Ni, Pb, and Se when supplied individually in a nutrient solution at a series of concentrations ranged from 0.1 to 10 mg L -1 . The results show that under experimental conditions, duckweed proved to be a good accumulator of Cd, Se, and Cu, a moderate accumulator of Cr, and a poor accumulator of Ni and Pb. The highest concentrations of each trace element accumulated in duckweed tissues were 133 g Cd kg -1 , 4.27 g Se kg -1 , 336 g Cu kg -1 , 2.87 g Cr kg -1 , 1.79 g Ni kg -1 , and 0.63 g Pb kg -1 . Duckweed exhibited some symptoms of toxicity (e.g, reduced growth, chlorosis) at higher levels of element supply (except for Cr). The toxicity effect of each trace element on plant growth was, in descending order of damage, Cu > Se > Pb > Cd > Ni > Cr. We conclude that duckweed shows promise for the removal of Cd, Se, and Cu from contaminated wastewater since it accumulates high concentrations of these elements. Further, the growth rates and harvest potential make duckweed a good species for phytoremediation activities.
Thermal Behavior of Isotactic Poly(propylene)/Maleated Poly(propylene) Blends

This paper analyzes the thermal and thermo-oxidative degradation behavior, phase separation, melting, and crystallization of blends consisting of isotactic poly(propylene) (IPP) and poly(propylene) grafted with maleic anhydride (PP-g-MA). It has been established that, depending on the blend composition and crystallization/preparation procedure, the blends of IPP and PP-g-MA can either co-crystallize or evidence phase separation. This conclusion has been attained by comparing the DSC results of crystallization under dynamic and isothermal conditions with X-ray diffraction results. On the basis of the obtained results, the optimum mixing ratios have been established as 95-85 wt. -% IPP/ 5-15 wt. -% PP-g-MA. Thermo-oxidative behavior has been studied by thermogravimetry and differential thermal analysis.
Energy Analysis of Poly-hydroxybutirate (PHB) Drying Using a Combined Microwave/Rotating Pulsed Fluidized Bed (MW/RPFB) Dryer

The aim of this study was to investigate the drying kinetics and energy efficiency of a combined microwave/rotating pulsed fluidized bed (MW/RPFB) dryer to dry particles of poly-hydroxybutirate (PHB). In order to analyze the effects of microwaves and hot air conditions on the drying kinetics of PHB and energy efficiency, an experimental design technique was applied. Drying energy efficiencies were in the range of 12–30%, and an estimated value of 10.5% was found for pure convective drying of PHB in an RPFB with the same final moisture content.
Efeito da aplicação de água residuária de suinocultura no solo e na qualidade dos seus lixiviados

Este trabalho avalia o comportamento da agua residuaria de suinocultura, quanto aos seus efeitos no solo e na qualidade dos seus lixiviados. Na incubacao do solo com efluente, foram utilizadas 48 unidades experimentais no total com taxas de aplicacao de 0, 50, 100 e 150 m3.ha-1. O pH do solo e lixiviados apos asdiferentes taxas de aplicacao permaneceu acido e os valores de amonia nos argissolos apresentaram valores menores do que no solo testemunha enquanto que nos nitossolos houve aumento em funcao das taxas de aplicacao. A capacidade de troca cationica aumentou com maior intensidade nos argissolos. A relacao carbono/nitrogenio foi baixa evidenciando uma mineralizacao rapida dos residuos orgânicos. Os valores de nitrato no primeiro lixiviado e de fosforo nos nitossolos foram maiores do que nos argissolos, em funcao da taxa de aplicacao.
Indium tin oxide spreading layers for AlGaInP visible LEDs

In this paper the effectiveness of indium tin oxide (ITO) is assessed as a current spreading layer (CSL) for AlGaInP visible light emitting diodes (LEDs). A range of device structures has been fabricated in order to test the CSL characteristics. As a basis for this comparison test devices have been fabricated both with and without any ITO spreading layers and for comparison with an alternative GaP spreading layer. These measurements confirm that ITO is an effective alternative to the GaP structure with greater potential for applications in low-cost LED arrays.
Efficient Ring Opening of Aziridines with Carboxylic Acids

Abstract An efficient ring cleavage of aziridines with acids has been studied in the absence of any catalyst. The hydrolysis of the products, amino esters, leads to the corresponding amino alcohols. The reaction has been extended to chiral cycloalkyl aziridines, leading to the formation of diastereomers. After separation, these diastereomers have been converted to optically pure amino alcohols in two steps.