Miracle-dz/UniFAR-FTUs huggingface dataset:
Optical Absorption Study of the Surface Plasmon Resonance in Gold Nanoparticles Immobilized onto a Gold Substrate by Self-Assembly Technique

The resonance wavelength of the surface plasmon in gold nanoparticles above a gold substrate has been measured using transmission absorption spectroscopy. Gold nanoparticles with diameters in the range of 20−100 nm are immobilized onto a thin gold film deposited onto a glass substrate by a self-assembled monolayer of aminoethanethiol. The resonance wavelength obtained in the experiments shows a large red shift. Its dependence on the particle diameter shows good agreement with theoretical results that are calculated using a static approximation that includes multipole effects.
COLOR CHANGE KINETICS OF CELERY LEAVES UNDERGOING MICROWAVE HEATING

The aim of this study was to investigate the effect of microwave output power and sample amount on color change kinetics of celery leaves (Apium graveolens L.) during microwave heating. The color parameters of the materials were quantified by the Hunter Lab system. These values were also used for calculation of the total color change, chroma, hue angle, and browning index. The microwave heating process changed color parameters of L, a, and b, causing a color shift towards darker region. The mathematical modeling study of color change kinetic showed that L, a, b, and chroma fitted to a first-order kinetic model, while total color change (ΔE), hue angle, and browning index (BI) followed a zero-order kinetic model. For calculation of the activation energy for color change kinetic parameters, the exponential expression based on the Arrhenius equation was used.
Effect of Carbon and Energy Source on Bacterial Chromate Reduction

Studies were conducted to evaluate carbon and energy sources suitable to support hexavalent chromium (Cr(VI)) reduction by a bacterial consortium enriched from dichromate-contaminated aquifer sediments. The consortium was cultured under denitrifying conditions in a minimal, synthetic groundwater medium that was amended with various individual potential carbon and energy sources. The effects of these individual carbon and energy sources on Cr(VI) reduction and growth were measured. The consortium was found to readily reduce Cr(VI) with sucrose, acetate, L-asparagine, hydrogen plus carbon dioxide, ethanol, glycerol, glycolate, propylene glycol, or D-xylose as a carbon and energy source. Minimal Cr(VI) reduction was observed when the consortium was cultured with citrate, 2-ketoglutarate, L-lactate, pyruvate, succinate, or thiosulfate plus carbon dioxide as a carbon and energy source when compared with abiotic controls. The consortium grew on all of the above carbon and energy sources, with the highest cell densities reached using D-xylose and sucrose, demonstrating that the consortium is metabolically diverse and can reduce Cr(VI) using a variety of different carbon and energy sources. The results suggest that the potential exists for the enrichment of Cr(VI)-reducing microbial populations in situ by the addition of a sucrose-containing feedstock such as molasses, which is an economical and readily available carbon and energy source.
An electron microscope study of evaporating small particles: the Kelvin equation for liquid lead and the mean surface energy of solid silver

An electron microscope study of evaporating liquid lead particles, formed on carbon substrates by nucleation from the vapour, has led to a confirmation of the Kelvin equation which relates equilibrium vapour pressure to surface curvature. Observations of the same kind made on particles of evaporating solid silver have produced evaporation curves similar to those for lead. Interpretation of these curves in terms of the Kelvin equation for solids has yielded a value for the mean surface energy of silver of 1.20 ± 0.06 J m-2 (1200 ± 60 erg cm-2) at 1005 ± 25 K.
Effect of production site, storage duration, and hot water and molybdenum dips on bioactive compounds with antioxidant properties in lemon flavedo during cold storage

Certain bioactive compounds, such as vitamin E (α-tocopherol), vitamin C (ascorbic acid), β-carotene, polyphenols (e.g. flavonoids and flavonones, viz. hesperidin and naringin) have antioxidant properties and their presence in the citrus flavedo plays a significant role in mitigating oxidative stress, which could possibly result in chilling injury during cold storage. The purpose of this investigation was, therefore, to alter the concentration of these bioactive compounds in lemon flavedo using hot water and molybdenum (Mo) treatments prior to cold storage to allow fruit to withstand such storage, and avoid the occurrence of chilling injury. Fruit from three sources (Ukulinga Farm, Sun Valley and Eston Estates) were treated for 2 min with hot water dips (HWD) (at 47 °C or 53 °C) with or without a subsequent soaking in 1 or 10 µM Na2MoO4 for 30 min. Fruit were then stored at -0.5 °C for up to 7, 14, 21 or 28 d and thereafter moved to room temperature (±21 °C and ±68% RH) for 7 d. Lemon fruit from Sun Valley Estates were chilling-susceptible and had the lowest concentration of bioactive compounds, significantly lower than chilling-resistant fruit from Ukulinga Farm. Application of HWD at 53 °C, as well as 1 µM Mo in combination with HWD at 53 °C, enhanced the flavedo concentration of bioactive compounds. Furthermore, storage duration seemed to induce an increase or decrease in flavedo bioactive compounds concentration. In general, HWD and Mo dips enhance the rind concentration of phenolics and ascorbic acid at specific storage times.
Di-μ-acetato-κ4O:O′-bis­[bis­(2,2′-bipyridine-κ2N,N′)manganese(II)] bis­(perchlorate)

In the binuclear title manganese(II) complex, [Mn2(C2H3O2)2(C10H8N2)4](ClO4)2, the Mn atoms are six-coordinate in a distorted octa­hedral coordination geometry. The two Mn atoms are bridged by two acetate groups to form a dimeric cation. The complex forms chains through π–π stacking inter­actions.
A complete basis set model chemistry. VII. Use of the minimum population localization method

It is shown that localization is necessary to preserve size consistency in nonlinear extrapolations of molecular energies. We demonstrate that the unphysical behavior of Mulliken populations obtained from extended basis set wave functions can lead to incomplete localization of orbitals by the Pipek–Mezey population localization method, and introduce a modification to correct this problem. The new localization procedure, called minimum population localization, is incorporated into the CBS-QB3 and the new CBS-4M model chemistries, and their performance is assessed on the G2/97 test set. The errors found for CBS-QB3 are comparable with those for the G3 and G3(MP2) (mean absolute deviation of 1.10, 0.94, and 1.21 kcal/mol, respectively, on the G2/97 test set). The CBS-4M is less accurate than the other models (mean absolute deviation of 3.26 kcal/mol on the G2/97 test set), but can be applied to much larger systems. The modified localization method resolves several problem cases found with CBS-4 and improves the reliability of CBS-QB3.
Insights into Ion-Network Interactions and Ion Transport in Glass

Zusammenfassung We discuss the origins of mixed-former effects in borophosphate glasses of general composition: Li0.5BO1. 75:(1−x)LiPO3 and 0.4 Na2O:0.6 [xB2O3:(1−x)P2O5], and show how these effects relate to changing ion-network interactions. In particular for the latter system, we analyse the permittivity spectra using the MIGRATION concept. The results show that the increase in the calculated “cage length” (spatial extent of localised ion motion) in the mixed former region correlates well with the increased abundance of the BO4 tetrahedra. We propose that more local cation sites are created and fast electronic bond-switching processes open up these sites to facilitate macroscopic transport. This picture of ion transport independent of network dynamics accounts for all favourable effects observed in mixed former glasses such as increase in ion mobility, rise in Tg and improvement in chemical durability.
Dairy manure influences on phosphorus retention capacity of Spodosols

Land areas used for dairy farming can result in accumulation of manure on soils that could produce nutrient-rich surface and subsurface runoff and cause accelerated lake eutrophication. This research was conducted on Spodosols that were differentially impacted by manure; the study included sites with different levels of total P (TP), from 2300 mg kg -1 in the soil highly impacted by intensive dairy farming to 18 mg kg -1 in an unimpacted area. The P retention characteristics of these soils were determined by using both single-point (1000 mg P kg -1 or 100 mg P L -1 ) and traditional Langmuir isotherms. Phosphorus sorption values using a single high P solution had approximately a 1:1 relationship with values obtained for the maximum retention capacity, S max , obtained from Langmuir isotherms (r 2 = 0.98). The surface A and E horizons of manure-impacted soils had essentially no sorbing capacity while the Bh (spodic) and Bw horizons had mean S max values 430 and 385 mg kg -1 , respectively. The P sorbing capacity of the Bh and Bw horizons were attributed to high Al concentrations in these horizons. Higher P concentrations in the surface A horizon resulted in greater P concentrations in solutions equilibrated with the Bh- and Bw- horizon materials, which suggests a potential for vertical P movement through the soil profile. The spodic horizon of the less-impacted soils may not have been exposed to sufficiently high solution P concentrations to accumulate significant P in the soluble fraction.
Biotrickling Filtration of Biogas Produced from the Wastewater Treatment Plant of a Brewery

AbstractThe performance of a lab-scale biotrickling filter treating H2S from biogas produced from an upflow anaerobic sludge bed reactor of the wastewater-treatment plant of a brewery was evaluated. A sulfide-oxidizing culture obtained from the anaerobic sludge of the same upflow anaerobic sludge bed reactor was immobilized on polyurethane foam. The nitrate and nitrite (final electron acceptor) depletion on the trickling medium resulted in remarkable destabilization in the performance of the system. The optimum temperature was in the range from 31 to 42°C (removal efficiency=91.8±5.5%). At a temperature of 22°C the removal efficiency reduced to 39% [inlet load (IL)=5.3 gS-H2S m−3 h−1, empty bed residence time (EBRT)=2.9 min]. Trickling liquid velocity (TLV) of 4.4, 7.4, and 11 m h−1 did not affect the system at EBRT of 6.2 min (removal efficiency=94.2±1.3%, IL=1.86±0.18 gS m−3 h−1). A TLV effect was observed at an EBRT of 1.6 min where the removal efficiency decreased from 50.9% (4.4 m h−1) to 33.7%.
Vanadium L2,3 XANES experiments and first-principles multielectron calculations: Impact of second-nearest neighboring cations on vanadium-bearing fresnoites

Abstract Transition-metal L2,3 XANES spectra are widely used to determine coordination and valence of the target ion. For decades, experimental fingerprinting, i.e., the comparison with spectra obtained from known reference compounds was the way to interpret spectral features. This approach was based on the common understanding that only anions in the first coordination sphere would determine the nearedge structure, and crystalline references were selected accordingly. Using ab initio charge-transfer multiplet calculations, we demonstrate that there is also a significant impact on spectral features from the second-nearest neighbor cations. This finding is exemplified for three fresnoite-type vanadates, namely Ba2VSi2O8 (BVS), K2VV2O8 (KVV), and Rb2VV2O8 (RVV). The theoretical treatment provides evidence that for the three compounds studied it is not variable bond lengths or bond angles between vanadium and oxygen that make the V-L2,3 XANES spectra different, but the interaction of the target vanadium ions with its neighboring cations (Si for BVS, V for KVV and RVV), which dominates. Therefore, we conclude that simple fingerprinting can result in misleading interpretations when interactions with second-nearest neighboring cations are not taken into account. Ab initio charge-transfer multiplet calculations of spectral shapes (theoretical fingerprinting) should be employed instead to get a deeper understanding of structure-spectra relationships, or the choice of reference spectra should take into account second-nearest neighbors. Our findings are similarly important for the interpretation of electron energy-loss near-edge (ELNES) spectra.
Synthesis and Structural Characterization of Tetradentate (N2O2) Ligand Complexes of Zinc

The potentially tetradentate-N2O2 ligands, N,N′-bis (o-hydroxybenzyl)-1,2-diaminoethane (SaleanH4), N,N′-bis(o-hydroxybenzyl)-1,3-diaminopropane (SalpanH4), N,N′-bis(o-hydroxybenzyl)-1,4-diaminobutane (SalbanH4), N,N′-bis(o-hydroxybenzyl)-1-6-diaminohexane (SalhanH4), N,N′-bis(o-hydroxybenzyl)-1,2-diaminobenzene (SalophanH4), and N, N′-bis (o-hydroxybenzyl)-1,2-dimino-4,5-dimethylbenzene (SalomphanH4), have been synthesized and used to prepare the series of zinc complexes, [SaleanH2Zn]2 (1), [Salpan H2Zn]2 (2), [SalbanH2Zn]2 (3), [SalhanH2Zn]2 (4), [SalophanH2Zn]2 (5), and [Salomphan H2Zn]2 (6), Compounds (2) and (5) have been structurally characterized with single-crystal x-ray diffractometry. The molecules consist of oxygen-bridged zinc dimers. Unique structures for (5) were determined from crystals grown from MeOH (5a) and DMF (5b). The structures possess varying numbers of solvent molecules in the unit cell. Crystal Data: (2) Space Group P1 with a = 13.076(3) A, b = 13.137(3) A, c = 13.228 (3) A, α = .
Model for oxygen transfer in a shake flask

The shake flask is a very common and useful tool for the study of submerged fermentations on a small scale. However, the oxygen supply may easily become a limiting factor. A model for the aeration in shake flasks is presented that enables one to predict whether in the course of an experiment the oxygen supply is becoming a growth‐limiting factor or not. The results of measurements of the transfer coefficient of a cotton plug and the oxygen mass‐transfer coefficient kla are also given.
Vibrational analysis of a Hylleraas‐configuration interaction potential for H+3

The potential surface for H+3, obtained from Hylleraas configuration interaction calculations by Frye et al. [J. Chem. Phys. 92, 4948 (1990)], has been fitted to a seventh‐degree polynomial in Morse–Dunham coordinates to study the low‐lying vibrational states of H+3, D+3, H2D+, D2H+, H2T+, and T2H+. Vibrational levels of up to two quanta excitations are reported and compared with experiments and other theoretical calculations. There are indications that adiabatic corrections may be important in correcting the small errors in the calculated vibrational quanta. The exothermicity of the proton‐transfer reaction between H2 and H+2 predicted is 1.685 eV, to be compared with the experimental value of 1.7 eV. The calculated dissociation energy for H+3 is 4.337±0.002 eV, 355 cm−1 smaller than the experimental value of 4.381±0.021 eV. No source of discrepancy from theoretical side can be identified.
Assessing photosynthetic light-use efficiency using a solar-induced chlorophyll fluorescence and photochemical reflectance index

Photosynthetic light-use efficiency (LUE) is an important indicator of plant photosynthesis, but assessment by remote sensing needs to be further explored. In this study, two protective mechanisms for photosynthesis, chlorophyll fluorescence (ChlF) and heat dissipation in the deep oxidation state of the xanthophyll cycle, were explored to estimate photosynthetic LUE from canopy radiance spectra. Four independent experiments were carried out on summer maize (C4 plant) on 5 July 2008, and winter wheat (C3 plant) on 18 April 2008, 16 April 2010, and 13 May 2010, by synchronously measuring daily canopy radiance spectra and photosynthetic LUE. The competitive relationship between ChlF and photochemical yield made it possible to estimate photosynthetic LUE. LUE–ChlF models were developed for ChlF at 688 nm (R 2 = 0.72) and 760 nm (R 2 = 0.59) based on the experimental data from 13 May 2010 at the Guantao flux site. The LUE–ChlF models were validated by three independent experiments, and the results showed that the LUE–ChlF relationship was weakened, possibly by variation in species, canopy density, and environmental conditions. As an easy, rapid, non-intrusive method, a photochemical reflectance index (PRI) provides an instantaneous assessment of dynamic photosynthetic LUE. The significant negative relationship between non-photochemical quenching and PRI was confirmed. Although there was a significantly positive relationship between LUE and PRI in all four independent experiments, this was evidently weakened by the canopy and environmental conditions. Difference in PRI (ΔPRI) from the minimum reference PRI around noontime can largely eliminate interference factors. The LUE–ΔPRI model was developed based on experimental data from 13 May 2010 at the Guantao flux site (with an R 2 value of 0.85), and validated by the three other independent experiments. The validation result indicated that different species can markedly affect the precision of the PRI difference method.
Solvothermal Synthesis of Metastable γ‐MnS Hollow Spheres and Control of Their Phase

A solvothermal route has been developed to prepare metastable wurtzite-structure γ-MnS hollow spheres from anhydrous manganese chloride, sulfur powder, and potassium borohydride in ethylene glycol at 150–180 °C. The metastable γ-MnS and stable α-MnS were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electronic microscopy, scanning electron microscopy, transmission electron microscopy, and photoluminescence. Experiments show that the reaction temperature, the solvent, and the concentration and reducibility of the reductant are the crucial factors affecting the phase of the product. A possible growth mechanism for the hollow sphere is proposed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Overview of MedeA®-GIBBS capabilities for thermodynamic property calculation and VLE behaviour description of pure compounds and mixtures: application to polar compounds generated from ligno-cellulosic biomass

This paper illustrates the use of Monte Carlo (MC) simulations to study a wide range of systems of interest for biomass conversion into high-added value chemicals and biofuels. The interest is focused on the use of molecular simulation to predict the physical–chemical properties of pure compounds and mixtures at a wide range of temperature and pressure conditions, as well as to provide insight on the mechanisms involved and the molecular characteristics that are related to the macroscopic behaviour of such complex systems. A systematic scaling study has been performed in which our implementation of the MC method is scaled well up to 4 to 12 processors. We have automated tasks such as the implementation of default MC frequencies, statistical parameters, convergence analysis and determination of statistical averages. On this basis, we could determine the equilibrium properties for approximately 100 compounds (alcohols, ethers, ketones, aldehydes, esters, glycols) with the TraPPE-UA and the anisotropic united atoms (AUA) forcefields. TraPPE-UA provides a good prediction of liquid density, and AUA provides a better determination of saturation pressures and normal boiling temperature. Liquid–vapour phase diagrams of binary mixtures are also provided to illustrate the predictive capability of MC simulations. Viewing graphs or configurations allows to validate convergence analysis and to understand the hydrogen-bonded systems.
CORPORATE CHARACTERISTICS AND EARNINGS MANAGEMENT OF LISTED OIL AND GAS FIRMS IN NIGERIA

This study examines the relationship between corporate characteristics and earnings management of listedoil and gas firms in Nigeria for the period 2006 to 2015. Data was obtained from a sample of seven firmsout of the population of nine firms through their annual report and accounts. Corporate characteristics asan independent variable was proxied by firm size, leverage, dividend and profitability, while the residualsfrom the modified Jones Model by Dechow et al (1995) was used to represent earnings management asdependent variable. The study adopted ordinary least square multiple regression technique in analyzingdata. The findings revealed that firm size have significant positive impact on earnings management,leverage have insignificant negative impact on earnings management, dividend has insignificant positiveimpact on earnings management and profitability have insignificant negative impact on earningsmanagement of the listed oil and gas firms. It is recommended that the firms in Nigeria should reduce thescope of their operations and also be caution in paying dividend to their shareholders, since the resultreveals evidence that firm size have positive significant influence on earnings management and dividendhave positive insignificant influence on earnings management. Also, the firms in Nigeria should initiatestrategies that will enable them to generate more profit as well as increasing the level of leverage in theircapital structure, since both profitability and leverage have negative insignificant impact on earningsmanagement.
The effect of ENSO activity on lower stratospheric water vapor

Abstract. Using the ECMWF/NCEP reanalysis data, satellite observations from AURA MLS and UARS HALOE, and Oceanic Nino Index (ONI) data, the effects of El Nino and La Nina events on the stratospheric water vapor changes are investigated. Overall, El Nino events tend to moisten the lower stratosphere but dry the middle stratosphere. La Nina events are likely to dry the lower stratosphere over a narrow band of tropics (5° S–5° N) but have a moistening effect on the whole stratosphere when averaged over a broader region of tropics between 25° S–25° N. The moistening effect of La Nina events mainly occurs in lower stratosphere in the Southern Hemisphere tropics where a significant 20% increase in the tropical upwelling is caused by La Nina events. El Nino events have a more significant effect on the tropical upwelling in the Northern Hemisphere extratropics than in Southern Hemisphere extratropics. The net effect of ENSO activities on the lower stratospheric water vapor is stronger in the Southern Hemisphere tropics than in the Northern Hemisphere tropics.
Quest for high brightness, monochromatic noble gas ion sources

Focused ion beam (FIB) machines are key tools for state-of-the art sample preparation in electron microscopy, for characterization and repair in material sciences, for the semiconductor industry and for nanotechnology in general. Liquid-metal ion sources (LMIS) are widely used in FIB machines because they meet the minimum ion source requirements such as source brightness and reliability. However, in FIB machines, noble gas ion sources are favorable for sputtering, beam-induced etching and deposition, because the implanted ions do not change the electrical behavior of the substrate significantly. There are several efforts by various researchers to develop noble gas ion sources that can be used in FIB machines instead of LMIS. The gas ion sources could not meet the minimum ion source requirements. Therefore, LMIS are still a popular choice among FIB machine users. This review article takes a critical look at the reported efforts in the literature to develop noble gas ion sources for FIB machines.