Miracle-dz/UniFAR-FTUs huggingface dataset:
Histogram of number of particles as an indicator for 2D phase transition in adsorption of gases on graphite

Grand canonical Monte Carlo simulation is used to study the adsorption of gases with strong and weak molecular interaction on graphite. We choose nitrogen adsorption at 77 K, ethylene at 104 K, methanol at 240 K and ammonia at 300 K as model examples. The adsorption mechanism of these species can be studied by analysing the radial distribution and the ‘number of particles histogram’ as a function of loading. At low pressures, at which the surface is barely covered with molecules, nitrogen and ethylene adsorb in a similar manner, while ammonia and methanol show a distinct difference because of the formation of clusters, resulted from the hydrogen bonding. Small clusters are observed for methanol and larger ones for ammonia, which is in agreement with the fact that hydrogen bonding is more significant in ammonia than in methanol. Analysis of the number of particles distribution can identify 2D phase transition as a sudden shift of the peak in the number histogram as exemplified with the adsorption of ethylene at 104 K and ammonia at 300 K.
Removal of rock fragments and its effect on soil loss and crop yield, Tigray, Ethiopia

Abstract. When the farmers of the Highlands of Tigray (northern Ethiopia) consider rock fragment cover in their fields to be excessive, they remove some of them. In addition, large amounts of rock fragments of all sizes are removed from fields for building stone bunds. Semi‐structured interviews indicate that the farmers are often reluctant to take away the smaller rock fragments (i.e. < 5 cm across) from their fields, since they believe these benefit soil moisture conservation and protect topsoil from erosion. A field experiment was carried out on a Vertic Cambisol (average slope: 0.125 m m–1), 2 km east of Hagere Selam (subhumid climate). Rock fragments were totally, partially or not removed from the 12 runoff plots (5 m × 6 m) before the beginning of the 1999 cropping season, during which a local mixture of wheat varieties (Triticum spp.) was sown. After harvest, erosion rates were assessed by measuring deposited sediment volume in trenches at the lower side of each subplot, and grain and straw yields were assessed. We found a significant negative relationship between rock fragment cover and soil loss by water erosion. However, the resulting positive relationship between rock fragment cover and grain and straw yield was weak. This might be explained by the fact that the plot did not suffer from drought due to soil and climatic conditions. Detailed analysis showed that cover by medium and large rock fragments (> 2 cm diameter) showed an optimum percentage cover above which crop yields decrease. A recommendation resulting from this study is to rely on the farmers’ experience: smaller rock fragments should never be removed from the surface of fields during soil and water conservation works; instead rock fragment rich soil can be used to top the stone bunds.
Maximum Simplification of the Dynamic Equations

When the dynamic equations are to be used to further our understanding of atmospheric phenomena, it is permissible to simplify them beyond the point where they can yield acceptable weather predictions. Through the use of double Fourier series, and with the omission of all but the largest scales of motion, the barotropic vorticity equation may be reduced to a system of three ordinary nonlinear differential equations. The analytic solutions of these equations are elliptic functions of time. The equations may also be solved rapidly by numerical integration. Particular solutions of the equations picture the motion of finite disturbances on a zonal flow, with exchanges of kinetic energy between the zonal flow and the disturbances accompanying the meridional transport of zonal momentum by the disturbances. Other solutions picture the initial growth and eventual cessation of growth of small disturbances on an unstable zonal current. Still further solutions picture the destruction of a stable zonal flow by large disturbances, and lead to a plausible hypothesis concerning index cycles in the atmosphere. Less extreme simplifications of the dynamic equations may be used when more complicated atmospheric phenomena are to be studied. DOI: 10.1111/j.2153-3490.1960. tb01307.x
Antioxidant Activity of Compounds Isolated from the Root Woods of Erythrina droogmansiana

The aim of this study was to isolate, to characterize secondary metabolites from methanolic extract of the root woods of Erythrina droogmansiana and to assess the antioxidant activity of the crude extract and isolated compounds. The phytochemical study led to the isolation of 3-(3’,4’-methelenedioxyphenyl)-2,3-epoxypropanol (1), asperphenamate (2) and three flavonoids namely genistein, diadzein and 4’,5,7-trihydroxy-8-prenylisoflavone. These compounds were characterized using their
Probing the chemical and surface chemical modification of vessel cell walls during bleaching of eucalyptus pulp

Abstract Eucalyptus pulp is increasingly used for the manufacture of printing papers. However, its major drawback, the vessel picking, is still waiting for a solution. The detailed features and the characteristic behaviour of vessel elements (VEs) in pulp and paper processes are poorly understood. This study focusses on the chemistry, surface chemistry and morphology of eucalyptus VEs. These properties were followed through the changes introduced by different stages of elemental chlorine-free (ECF) bleaching, by studying separated VEs. Microprobe X-ray photoelectron spectroscopy (μ-XPS) and field emission-scanning electron microscopy (FE-SEM) were applied to elucidate the surface chemical composition and morphological ultrastructure, respectively. The bulk chemical composition was investigated among others by Py-GC/MS. Lignin was detected in vessels still after completed bleaching sequence, whereas the fibres were lignin-free. The vessel lignin was mainly composed by syringyl-type units. Surface coverage by lignin and amount of surface anionic groups were practically unaffected by bleaching. The vessel cell wall structure was observed to be layered in a complex way with no particular orientation of cellulose fibrils, and the different layers seemed to be exfoliated during different bleaching stages.
Evaluation of Thermal Effects on the Dissolution of a Nonaqueous Phase Liquid in Porous Media

Porous media contaminated with nonaqueous phase liquids (NAPLs) may serve as a long-term source of groundwater contamination. To remove NAPLs and thereby mitigate the potential impact to the environment and human health, it has been suggested that contaminated media be flushed with cosolvents, surfactants, hot water, or steam. In this study, hot water flooding was used to remediate a porous medium contaminated with tetrachlorethylene (PCE) at residual saturation in an otherwise water-saturated medium. The effect of temperature on the physical and chemical properties of the system was well characterized, and a quantitative assessment was made of the effect of temperature on PCE dissolution. A comparison of the results from the dissolution experiments with existing dimensionless correlations for NAPL dissolution in porous media elucidated the role of the aqueous-phase viscosity and the NAPL species aqueous-phase diffusivity. Nonaqueous−aqueous phase mass transfer rate coefficients measured for this system w.
Nitrous oxide emissions from three ecosystems in tropical peatland of Sarawak, Malaysia

Abstract Nitrous oxide (N2O) emissions were measured monthly over 1 year in three ecosystems on tropical peatland of Sarawak, Malaysia, using a closed-chamber technique. The three ecosystems investigated were mixed peat swamp forest, sago (Metroxylon sagu) and oil palm (Elaeis guineensis) plantations. The highest annual N2O emissions were observed in the sago ecosystem with a production rate of 3.3 kg N ha−1 year−1, followed by the oil palm ecosystem at 1.2 kg N ha−1 year−1 and the forest ecosystem at 0.7 kg N ha−1 year−1. The N2O emissions ranged from –3.4 to 19.7 µg N m−2 h−1 for the forest ecosystem, from 1.0 to 176.3 µg N m−2 h−1 for the sago ecosystem and from 0.9 to 58.4 µg N m−2 h−1 for the oil palm ecosystem. Multiple regression analysis showed that N2O production in each ecosystem was regulated by different variables. The key factors influencing N2O emissions in the forest ecosystem were the water table and the NH+ 4 concentration at 25–50 cm, soil temperature at 5 cm and nitrate concentration at 0–25 cm in the sago ecosystem, and water-filled pore space, soil temperature at 5 cm and NH+ 4 concentrations at 0–25 cm in the oil palm ecosystem. R2 values for the above regression equations were 0.57, 0.63 and 0.48 for forest, sago and oil palm, respectively. The results suggest that the conversion of tropical peat swamp forest to agricultural crops, which causes substantial changes to the environment and soil properties, will significantly affect the exchange of N2O between the tropical peatland and the atmosphere. Thus, the estimation of net N2O production from tropical peatland for the global N2O budget should take into consideration ecosystem type.
Vibrational relaxation in the triplet state

Using monochromatic light from a frequency-doubled ruby laser and nanosecond time resolution, we have observed vibrational relaxation in the lowest triplet states of several aromatic vapours. A mechanism for vibrational relaxation is proposed and average amounts of energy removed per collision are determined for mixtures of buffer gas and anthracene. The pressure dependence of the triplet yield, upon excitation of anthracene at 347 nm, was also investigated.
Mass Spectrometry, Review of the Basics: Electrospray, MALDI, and Commonly Used Mass Analyzers

Abstract Mass spectrometry (MS) has progressed to become a powerful analytical tool for both quantitative and qualitative applications. The first mass spectrometer was constructed in 1912 and since then it has developed from only analyzing small inorganic molecules to biological macromolecules, practically with no mass limitations. Proteomics research, in particular, increasingly depends on MS technologies. The ability of mass spectrometry analyzing proteins and other biological extracts is due to the advances gained through the development of soft ionization techniques such as electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI) that can transform biomolecules into ions. ESI can efficiently be interfaced with separation techniques enhancing its role in the life and health sciences. MALDI, however, has the advantage of producing singly charges ions of peptides and proteins, minimizing spectral complexity. Regardless of the ionization source, the sensitivity of a mass spectrometer is related to the mass analyzer where ion separation occurs. Both quadrupole and time of flight (ToF) mass analyzers are commonly used and they can be configured together as QToF tandem mass spectrometric instruments. Tandem mass spectrometry (MS/MS), as the name indicates, is the result of performing two or more sequential separations of ions usually coupling two or more mass analyzers. Coupling a quadrupole and time of flight resulted in the production of high-resolution mass spectrometers (i.e., Q-ToF). This article will historically introduce mass spectrometry and summarizes the advantages and disadvantages of ESI and MALDI along with quadrupole and ToF mass analyzers, including the technical marriage between the two analyzers. This article is educational in nature and intended for graduate students and senior biochemistry students as well as chemists and biochemists who are not familiar with mass spectrometry and would like to learn the basics; it is not intended for mass spectrometry experts.
Studies on Acrylonitrile-Hydrozyalkyl-Methacrylate Copolymer Fibers

The effect cf wet spinning conditions on the properties of acrylonitrile-2-hydroxyethyl methacrylate (AN-HEMA) and acrylonitrile-2-hydroxypropyl methacrylate (AN-HPMA) copolymer fibers were studied. Copolymers containing 1 to 4.8 mole% hydroxyalkylmethacrylate comonomer were synthesized by slurry polymerization using redox initiator. The spinning dope used was a 15% solution of polymer in dimethylformamide. The spinning conditions studied were: extrusion pressure, coagulating bath temperature, take-up velocity, and draw ratio. Low coagulating bath temperature and high draw ratio gave fiber with better strength properties. Sonic modulus and x-ray diffraction were used for study ing the molecular orientation and crystalline organization. The influence of hydrophilic comonomers in polyacrylonitrile on moisture sorption, dyeability, and tensile properties was considered.
Effect of Water Absorption on Mechanical Properties of Sugar Palm Fibre Reinforced Sugar Palm Starch (spf/sps) Biocomposites

A novel biocomposite where both natural fibre and matrix are derived from underutilized parts of sugar palm tree was successfully developed. This 100% green materials can lead to solve depletion and non degradable polymer waste disposal problems. Unfortunately, since moisture absorption is a matter of concern in biocomposites, the effect of water absorption on mechanical properties of sugar palm fibre reinforced sugar palm starch (SPF/SPS) composites has been studied. From this investigation, it can be seen that tensile and impact strengths of biocomposites increase with the increase of fibre content. This enhancement indicates the effectiveness of the SPF to act as reinforcement for composites. But the mechanical properties of the biocomposites dropped after being stored for 72 hours at RH = 75%. In general, the weight gain due to water absorption of all biocomposites linearly increased with the increase of square root of immersion time and it tends to be more constant after a 48 h, following a Fickian diffusion process. Furthermore, moisture absorption decreased with the increase of sugar palm fibre (SPF) content. SEM micrographs showed good dispersion and adhesion between sugar palm starch (SPS) and SPF but large cracks appear on the surface of the matrix (SPS) due to water absorption.
A Novel Asymmetric Clamping Cell for Measuring Streaming Potential of Flat Surfaces

A novel asymmetric clamping cell is used to measure the ζ potential of macroscopic sample surfaces. The unique design of the cell allows in-situ measurement of ζ potentials of any flat surfaces, either solids (such as glass, plastics, metals, and ceramics) or flexible sheets (like polymer films, papers, foils, and membranes), without having to cut or shape the test surfaces to fit the measuring cell dimensions. The cell enables measurement of the streaming potential through several parallel rectangular channels formed by firmly pressing a grooved spacer against the test surface. The term “asymmetric” specifically refers to the unique configuration of the channels, where one of the walls (the test surface) bears a different charging property (or, more specifically, ζ potential), compared to the other three surfaces of the channel (formed by the spacer). A mathematical formulation on the basis of Smoluchowski−Helmholtz approach reveals that the measured ζ potential in such a cell represents the average ζ po.
Raman spectrum in PbTiO3 re-examined: dynamics of the soft phonon and the central peak

Light scattering measurements are investigated as a function of temperature from 10 to 900 K in the tetragonal and cubic phases of a PbTiO3 crystal. Phonon frequencies, ionic effective charges, spontaneous polarization and contribution to the dielectric permittivity are deduced from these data. The results show that the soft phonon and relaxation mode are both needed to describe the dynamics of this material.
Partial discharge detection in XLPE power cable with CT sensor

Partial discharge (PD) detection may be the most efficient and most sensitive diagnostic method for XLPE power cables and the potential effect of the discharge can be estimated on the basis of PD characteristics. A new method for detecting PD in XLPE power cables at VHF with a special designed wide frequency bandwidth current transducer (CT) is described in this paper. Quick sampling and digital processing of data based on wavelet and fractal. theory for PD diagnosis is presented to identify the nature of insulation defects causing discharge.
Metal complexes of a new ligand derived from 2,3-quinoxalinedithiol and 2,6-bis(bromomethyl)pyridine

The synthesis of a new ligand containing quinoxaline and pyridine subunits is described. The reaction of 2,3-quinoxalinedithiol with 2,6-bis(bromomethyl)pyridine leads to the isolation of bis(2-thio-3-mercaptoquinoxalino)-2,6-dimethylpyridine (L), which is a macrocyclic ligand precursor. The reaction of transition metal ions with L gives [M(L)X]X complexes (where M = Mn(II), Co(II), Cu(II), Ag(I), Zn(II), or Cd(II), and X = Cl or Br). The compounds were characterized by physical and spectroscopic measurements which indicated that the ligand is probably acting as a pentadentate NS4 chelating agent
Prediction of flow pattern for the co‐current flow of gas and non‐newtonian liquid in horizontal pipes

Previous work on delineating flow patterns for the horizontal two-phase flow of gas and Newtonian liquid is briefly described. One of the flow pattern maps has been slightly adjusted to take account of the evidence from more recent studies. It is shown that physical properties of the system have relatively little influence on flow regime. It is then established that this map is also applicable when the liquid shows shear-thinning non-Newtonian properties.
Elemental Carbon-Based Method for Monitoring Occupational Exposures to Particulate Diesel Exhaust

ABSTRACT Diesel exhaust has been classified a probable human carcinogen, and the National Institute for Occupational Safety and Health (NIOSH) has recommended that employers reduce workers' exposures. Because diesel exhaust is a chemically complex mixture containing thousands of compounds, some measure of exposure must be selected. Previously used methods involving gravimetry or analysis of the soluble organic fraction of diesel soot lack adequate sensitivity and selectivity for low-level determination of particulate diesel exhaust; a new analytical approach was therefore needed. In this paper, results of investigation of a thermal-optical technique for analysis of the carbonaceous fraction of particulate diesel exhaust are reported. With this technique, speciation of organic and elemental carbon is accomplished through temperature and atmosphere control, and by an optical feature that corrects for pyrolytically generated carbon, or “char,” which is formed during the analysis of some materials. The therma.
Screening For Microorganisms Possessing Phosphate Solubilizing Potential

Rhizosphere and non- rhizosphere soil samples from the agricultural fields of Indore and surrounding areas were collected for the isolation of phosphate solubilizing microorganisms. Soil samples which had been treated with herbicides, were also collected. Soils treated with herbicides like Pendimethalin, Triflusalin, Imaza 13, Squadron were screened for phosphate solubilizers. These soils contained very few bacterial species which could solubilize Phosphate. These species belonged mainly to the genus Bacillus and Pseudomonas. Among the fungal isolates from these soils were species of Aspergillus and Penicillium. The number of phosphate solubilizers in these treated soils was less as compared to untreated soils. However, Triflusalin treated soil had moderate number of phosphate solubilizers. Out of the 17 isolates 2 bacterial and 3 fungal cultures showing comparatively more solubilization ability during screening on Pikovskaya’s agar and Pikovskaya’s broth containing TCP were selected for their characterization
Electrons and holes in solar cells with partial rear contacts

When the metal contact of a silicon solar cell is restricted to a fraction of the rear surface, the flow of electrons and holes towards that contact is constricted, which is beneficial for minority charge carriers but detrimental for majority carriers. It is possible to describe their 2D/3D transport and determine their concentration in the vertical and transversal dimensions of the solar cell by separately studying the central region near the contact and the peripheral region surrounding it. A virtue of such geometric approach is that it establishes a link between analytical models and computer simulations, providing both physical insight and sufficient accuracy to optimise partial rear contact devices. In this paper, we extend a previous version of the geometric model to solar cells having a full‐area, locally contacted dopant diffusion on the rear surface. The case for n‐type versus p‐type wafers is considered, point contacts are compared with line contacts, including the impact of the metal/semiconductor resistance and bulk recombination is evaluated. Copyright © 2013 John Wiley & Sons, Ltd.
Self-assembled wire-like and honeycomb-like osmium nanoclusters (NCs) in DNA with pronounced catalytic and SERS activities

A new route to the formation of ultra-small Os nanoparticles (NPs) in DNA is reported. The Os NPs that are initially formed are self-assembled together to form Os nanoclusters (NCs) which have wire-like and honeycomb-like morphologies. The synthesis was carried out within a minute using microwave heating by the reaction of Os salt with ethanol. The size of the individual Os NPs varies between 1 and 3 nm and the synthesized particles are stabilized in DNA. The stable Os NCs showed a coupled SPR band near 600 nm in the visible region, which is useful for using the material as a potential SERS substrate. The SERS study was carried out using methylene blue (MB) as a model SERS probe molecule and the observed EF value is ∼107, which is much higher compared to a recent report for Os NPs. Apart from SERS, the Os NCs have also been tested in a catalysis reaction. The catalysis reaction was carried out for the first time for the reduction of organic nitro compounds in the presence of excess NaBH4. The catalytic reaction rate using Os NCs as a catalyst was found to be superior compared to earlier reports with other metal NPs, like Au or Ag. The improved catalytic and SERS activities of the Os NCs due to their ultra-small size with a high surface area might be useful in future in the field of biosensors, biomedicine, nano devices and other organic catalysis reactions.
Studies of the thermophysical properties of commercial CMSX-4 alloy

In this paper, measurements of the heat capacities and thermal diffusivities of commercial CMSX-4 nickel-based superalloy are described, and the results are presented. Since the as-received commercial alloy sample is not at the thermodynamic equilibrium state, the phases present in the alloy undergo transformations toward equilibrium state as the measurements are made at temperatures above which the rate of transformation can be significant. The microstructures of the as-received sample as well as heat treated samples were observed, and the relation with the properties was discussed. The results are discussed considering the phase changes occurring with the thermodynamic equilibrium state as the reference. The results are of great relevance in the performance of these alloys in industrial applications.
Acrylic Acid Grafted Polyester Surface: Surface Free Energies, FT-IR(ATR), and ESCA Characterization

The surface of polyester grafted with acrylic acid has been characterized using contact angle measurements of a two-liquid phase system and FT-IR and ESCA spectroscopy as a function of the concentration of acrylic acid on grafting. The COOH groups on the polymer surface influence only the polar component γs p of surface energy and not the dispersive one γs d. Both the FT-IR and ESCA characterizations, showing the transformation of COOH to COONa by alkaline treatment, provide information with a high degree of surface sensitivity, comparable to that of contact angle measurements. The relative area ratios of the COONa peak to the COOR peak by FT-IR ( A surface) and of the Na1 s peak to the C1 s peak by ESCA are linearly correlated to γs p.