Miracle-dz/UniFAR-FTUs huggingface dataset:
Influence of regulated deficit irrigation strategies applied to olive trees (Arbequina cultivar) on oil yield and oil composition during the fruit ripening period

This study evaluated the effect of regulated deficit irrigation (RDI) strategies applied to olive trees (Arbequina cv) during the fruit ripening and harvest periods on oil yield and oil composition. Fatty acid composition, pigments, colour, polyphenol content and stability of oils were evaluated. The results indicate that regulated deficit irrigation induces fruit ripening; at harvest, oil yield increased when water supply was decreased, probably as a consequence of lower water content in the olive. Acidic composition was not affected by irrigation treatments. Irrigation affected pigment content and oil colour primarily during the early stages of olive ripening. RDI increased polyphenol concentration and stability of oils at all picking dates, especially during the first stages of the ripening period, probably owing to water stress. © 2000 Society of Chemical Industry
Synthesis and characterization of high-quality polyaniline nanofibres

This article aims to study the synthesis of high-quality polyaniline (PANI) nanofibres through simple interfacial polymerization method in the presence of different acids. Ammonium persulphate, chloroform and different acids were used as oxidant, organic solvent and dopant, respectively. Field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) techniques were used to characterize the PANI nanofibres. FESEM results show different morphologies of PANI particles were produced from the various acid mixtures. FT-IR and XRD results confirmed the formation of PANI particles. XRD results show that PANI nanofibre is partially in crystalline nature.
Efficient screening of electron transport material in multi-layer organic light emitting diodes by combinatorial methods

A combinatorial approach combining vapor deposition of organic molecules and a mask technique was used to prepare on one substrate a matrix of 49 organic light emitting diodes (OLEDs) with different configurations and layer thicknesses. A landscape library with two orthogonal, linear gradients of an emitter and a hole blocking electron transport material on top of a hole transport layer of constant thickness was prepared. The aim of this experiment was to investigate the influence of an additional electron transport material on the efficiency. Using a semi-automated measurement set-up, the device parameters for each of the 49 OLEDs were evaluated. The existence of an optimum Alq3 layer thickness for ITO/TPD/Alq3/Al two-layer devices was confirmed and such an optimized two-layer structure could not be improved by adding an additional hole blocking layer to the optimum Alq3 layer. However, an improvement in photometric efficiency can be achieved by replacing the optimum Alq3 layer thickness by certain combinations of Alq3/spiro-quinoxaline layers.
Certification of Si powder diffraction standard reference material 640a

A new lot of high-purity silicon powder with mean crystallite size of about 6 μm has been certified as Standard Reference Material 640a. This SRM can be used as both an external and an internal 2θ calibration standard. The lattice parameter, uncorrected for refraction, is a = 5.430825(11) for λ(Cu Kα1) = 1.5405981 A at 298.1 K.
Photodissociation dynamics of propyne at 157 nm

Photodissociation of propyne at 157 nm has been investigated using photofragment translational spectroscopy. Detailed investigation of various photofragments from the deuterated compounds CD3CCH and CH3CCD, as well as the unlabeled propyne provides a uniquely clear picture of an inherently complex process. Hydrogen atom elimination processes from both the CH3 group and the C≡C–H group have been clearly observed. H atom elimination from the methyl group appears to be a single dynamical process, while ethynyl H elimination shows two distinctive dynamical pathways with a ratio of 0.30 (fast): 0.43 (slow). The relative contribution of the atomic hydrogen elimination from the two different sites was determined to be 0.73 (ethynyl): 0.27 (methyl). Molecular hydrogen elimination processes have also been observed, but with a much smaller yield compared to the atomic hydrogen elimination (1:9.6). Comparison of the H2 HD and D2 photoproducts from various deuterated propyne molecules shows that the molecular hydroge.
How to Improve the Energy Savings in Distillation and Hybrid Distillation‐Pervaporation Systems

Abstract As the worldwide demand for energy is growing, engineers are facing a challenge to design plants with minimum energy requirements. Distillation is an energy intensive process regardless of the products being separated. Using as an example the separation of alcohol–aqueous mixture, this article describes some options applicable to both revamp and new installations where the reduction of energy consumption is achieved. The “Hybrid” application is represented by the Water‐Tetrahydrofurane (THF) separation comparing a conventional two column Pressure Swing Distillation(PSD) system with a pressure distillation using a membrane unit. The main focus is on energy savings for a given separation problem trough the introduction of membrane unit.
Use of Measured Species Class Concentrations with Chemical Kinetic Modeling for the Prediction of Autoxidation and Deposition of Jet Fuels

The production of detrimental carbonaceous deposits in jet aircraft fuel systems results from the involvement of trace heteroatomic species in the autoxidation chain that occurs upon fuel heating. Although it has been known for many years that these sulfur-, nitrogen-, and oxygen-containing species contribute to the tendency of a fuel to form deposits, simple correlations have been unable to predict the oxidation rates or the deposit forming tendencies over a range of fuel samples. In the present work, a chemical kinetic mechanism developed previously is refined to include the roles of key fuel species classes, such as phenols, reactive sulfur species, dissolved metals, and hydroperoxides. The concentrations of these fuel species classes in the unreacted fuel samples are measured experimentally and used as an input to the mechanism. The resulting model is used to simulate autoxidation behavior observed over a range of fuel samples. The model includes simulation of the consumption of dissolved oxygen, as w.
Application of an all-solid-state ion-selective electrode for the automated titration of anionic surfactants

A poly(vinyl chloride) matrix membrane electrode responsive to anionic surfactants in an all-solid-state graphite–epoxy support was applied to the determination of anionic surfactants by potentiometric titration, using Hyamine 1622 as the titrant, in a pH 2.2 phosphate buffer. The results from this method compare favourably with those of the two-phase mixed indicator titration method for several commercial anionic surfactants (alkylsulfates, alkylbenzenesulfonates, α-alkene sulfonates, alkyl ether sulfates and sulfosuccinates). The performance characteristics improve the commercially available surfactant electrodes: the standard deviation for the titration of 4 mmol dm–3 dodecylsulfate with 4 mmol dm–3 titrant is 0.15%(n= 23), the relative standard deviation of the end-point potential is 0.95% and the average value of the potential jump is 140 mV, which allows for the titration of surfactants at concentrations down to 10 µmol dm–3 and shows its applicability in routine analysis.
X-ray and electron-beam lithography of three-dimensional array structures for photonics

The possibility to realize three-dimensional (3D) photonic crystals and the capability to internally insert a waveguide path poses a big challenge from the fabrication point of view. We present a fabrication method for a 3D lattice with designed linear defects by multitilt x-ray exposures and electron-beam lithography. This combination of different lithographies has been developed to control the design and the realization of the linear defects inside the three-dimensional structure. This method has been applied for the fabrication of Nickel Yablonovite lattices with a lattice parameter of 1.8 μm and a total thickness of 15 μm, a value that allows us to achieve a full three-dimensional optical behavior as confirmed by variable angle reflectance measurements.
Crystallization and vitrification in aqueous systems

Some key ideas and experimental findings concerning the probability that crystallization of a liquid or its binary solutions will occur at moderate cooling rates are discussed. The use of cryoprotectants and of pressure to favourably influence these probabilities is rationalized, and some of the newer findings on small sample supercooling phenomena are reviewed.
Determination of Arbutin, Niacinamide, and Adenosine in Functional Cosmetic Products by High-Performance Liquid Chromatography

A reversed-phase high-performance liquid chromatography method using a diode array detector at 260 nm was developed and validated for the determination of arbutin, niacinamide, and adenosine in cosmetics. The analytes were extracted using methanol and deionized water. The separations were performed on a C18 column with gradient elution. At the optimized conditions, the limits of detection for arbutin, niacinamide, and adenosine were 0.75, 0.12, and 0.01 µg/mL, respectively. The average recoveries were between 98.1% and 107.5%. The method was used to analyze thirty cosmetics.
Gallium orthophosphate device manufacturing by chemical etching

This paper presents a study of gallium orthophosphate chemical etching as a method to design high frequency AT resonators. The dissolution reaction was studied in phosphoric acid solutions and the equation of the dissolution kinetics was determined. The apparent dissolution rate depends both on the solvent and the solute concentrations at the solid-liquid interface and follows an Arrhenius type law in terms of temperature. In order to completely determine the kinetics at this interface, the rates of dissolution and nucleation processes were both established. The geometry and the density of etch figures appearing on the surface of the plates were observed using optical microscopy photographs. During the chemical dissolution, the surface quality was evaluated essentially through the measurement of the roughness average Ra parameter. The best surface state was obtained with solutions containing dissolved GaPO/sub 4/. Finally, resonators manufactured by the chemical etching process are characterized piezoelectrically by the air-gap method. These first results show that the Q factor (Q*F=1 to 1.5E+11) is not affected by the chemical etching process.
Montmorillonite-based nanocomposites of polybenzoxazole: Synthesis and characterization (I)

Poly(amic acid) was synthesized by means of low-temperature-solution polymerization of 3,3′-dihydroxybenzidine and pyromellitic dianhydride in N,N-dimethylacetamide. The precursor polymer was heat-treated at different temperatures to create a polybenzoxazole (PBO) through a polyimide (PI). PI containing the hydroxyl group was rearranged by decarboxylation with heat treatment, resulting in a fully aromatic PBO. Hexadecylamine was used as an organophilic alkylamine in organo-clay. We have tried to clarify the intercalation of heterocyclic polymer chains to hexadecylamine–montmorillonite (C16-MMT) and improve tensile properties. It was found that the addition of only a small amount of organo-clay was enough to improve the mechanical properties of PBO. Maximum enhancement in the ultimate tensile strength for PBO hybrids was observed for the blends containing 4% C16-MMT. The initial modulus monotonically increased with further increases in the C16-MMT content. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 471–476, 2001
Monitoring Micelle Formation of Nonionic Polyurethane in Water by Fluorescence Spectrophotometry

A series of nonionic polyurethanes were dissolved in water and their miceller self-assembly behaviors were characterized by aid of a fluorescence spectrophotometer. Fluorescence and resonance light scattering techniques were carried out for characterizing the micelles, and information such as aggregation number, critical micelle concentration, micropolarity, and micelle volume change was obtained. The micropolarity decreased as the aggregation number increased. The nonionic polyurethane micelle volume with two long ethoxyl chains per polyurethane molecule was smaller than the one with short chains, even with the same aggregation number, and was less polar. The micropolarity depended on both the aggregation number and the volume of a single micelle.
Anomalous Properties of the Vanadium Oxides

Vanadium oxides have outer 3d electrons that may be either localized or itinerant, depending upon the strengths of the cation-cation or cation-anion­ cation interactions. Properties of the AVOa perovskites show that vm+_02-_ Vm+ 'IT-bond interactions are strong enough to delocalize the 3d electrons if m :2:4, but not if m :::; 3. A critical V-V separation Rc ",,2.93 ±O.04 A, originally deduced from the properties of several isostructural series of compounds, is confirmed for an integral number of 3d electrons per cation by studies of VO", V20a, and V02. The high-temperature transition in V20a is shown to involve a band crossing as well as changes in the correlations among itinerant 3d electrons ; the low-temperature transition is shown to involve a dispro­ portionation of narrow-band electrons into localized and itinerant electrons. The two components of the semiconductor-to-metal transition in V02 are : the formation of bonded (R Re and fer­ roelectric-type displacements that create double d-orbital V-O bonds. The role of native defects in VO" and the "alloy problem" in mixed systems are briefly discussed. The Seebeck coefficient is used to characterize the sites available to small polarons in M" +V 20. -13 phases and several vanadium spinels. A critical V-V separation for small-polaron formation appears to be ReP ",, 2.97 A.
Preparation of Pd-containing TiO 2 film and its photocatalytic properties

The palladium-containing titanium dioxide films on glass substrate were prepared in a dip-coating process using a palladium-containing TiO2 sol. Following calcinations at 300°C, the authors rated the resulting film as having a hardness of 5 H as determined by a pencil scratch hardness tester. The photocatalytic activities were evaluated by decolourisation of methyl orange and degradation of NOx, respectively. Simple analysis was carried out using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence spectroscopy (PL) to observe changes in the film following palladium modification. Modification of TiO2 films with palladium enhanced the photocatalytic activity for decolourisation of dye and oxidation of NO.
Ultrasensitive and Simultaneous Determination of Arsenic and Antimony in Clinical Samples by Atomic Fluorescence Spectrometry

The determination of trace elements in human fluids facilitates the identification of metabolic disorders and physiological abnormities in clinical diagnosis. Elemental concentrations in serum, urine, and saliva are often low and highly prone to contamination. Consequently, a simple and ultrasensitive detection technique is required. In this study, a method was developed for the simultaneous determination of trace arsenic and antimony in clinical samples by hydride generation atomic fluorescence spectrometry. The experimental parameters that affect the generation, delivery, and atomization of volatile arsenic and antimony hydrides were investigated. The limits of quantification were calculated to be 0.0037 nanogram per milliliter and 0.0070 nanogram per milliliter for arsenic and antimony, respectively. The method was successfully applied for the analysis of fortified human serum, urine, saliva, and certified reference materials. The results obtained by the reported method were not statistically different from the certified values at the 95 percent confidence level.
Les sources thermales de Prony (Nouvelle-Calédonie) et leurs précipités chimiques. Exemple de formation de brucite primaire

In the Prony Bay (S.E. New Caledonia) there are many terrestrial and submarine thermal springs. Their chemistry is particularly noti- ccable since pH is still equal to 11 and caused by the only presence of ions OH- without any carbonate or bicarbonate. The cations are calcium and potassium. On ground, the thermal water flows taking charge of atmospheric CO, and precipitates in travertine. At sea, the spring precipitates in brucite Mg(OH), consequently to the mixing thermal water and sea water which supplies magnesium.
The Use of Computational Flow Modeling to determine Disinfection Efficacy of an Advanced Hydrodynamic Vortex combined Sewer Overflow Treatment System

The Problem A number of cities in Northeastern US are investigating the installation of new combined sewer overflow (CSO) treatment units utilizing an Advanced Hydrodynamic Vortex Separator (HDVS) with a self-cleansing screen. Hydrodynamic Vortex systems have traditionally been utilized as high-rate solids liquid separators and only recently have their potential use as contact chambers for high-rate disinfection of CSOs been realized. Conventional disinfection of CSOs, using mixed basins, relies on achieving contact times on the order of 15 minutes.
Structure and function of ECM-inspired composite collagen type I scaffolds

Collagen I is one of the most abundant molecules in vertebrates constituting major parts of the fibrillar extracellular matrix (ECM), thus providing structural integrity and mechanical resilience. It has therefore become an almost ubiquitous biomolecule to use in contemporary biomimetic cell culture scaffolds and in tissue engineering scenarios where new functions for biomedical applications are sought. As collagen I easily self-assembles into fibrillar structures, a number of approaches aim to integrate new functionalities by varying the compositional complexity of the developed scaffolds. Such composite matrices make use of the abundant knowledge about the fibrillar collagen I structure and its binding sites for other ECM molecules. This review gives an overview of the reconstitution of collagen I scaffolds by the implementation of other organic biomolecules. We focus on the self-assembly and structure of the collagen I fibrils affected by the interaction with cofactors and comment on mechanics and biomedical use of such composite scaffolds.
Crystal structure and revision of the chemical formula of georgiadesite, Pb4(AsO3)Cl4(OH)

Abstract The crystal structure of the rare secondary lead mineral georgiadesite has been solved from single-crystal X-ray diffraction data (R = 0.071). The structure can be visualized in terms of alternating puckered (100) layers of [Pbϕ6] octahedra and [Pbϕ8] bicapped trigonal prisms (ϕ = generic anion). Lead also occurs in irregular, lopsided polyhedra. This structural study shows unambiguously that arsenic occurs as As3+ and not as As5+. The chemical formula of georgiadesite has therefore been revised, on structural grounds, to Pb4(AsO3)Cl4(OH).
Separation of dipeptide and tripeptide enantiomers in capillary electrophoresis by the cationic cyclodextrin derivative 2‐hydroxypropyltrimethyl‐ammonium‐β‐cyclodextrin and by neutral β‐cyclodextrin derivatives at alkaline pH

The enantioseparation of dipeptides and tripeptides by the cationic CD derivative 2-Hydroxy-3-trimethylammoniumpropyl-β-cyclodextrin (TMA-β-CD) was studied under acidic and alkaline conditions. Enantioresolutions could be achieved at pH 3.5 when the peptides were partially positively charged, at pH 5.3 close to the isoelectric point of the peptides when the compounds are uncharged, and at pH 9.5 where the peptides exist as anions. Although not as effective as under acidic run conditions, native β-CD and neutral CD derivatives were able to resolve the enantiomers of several peptides at pH 9.5. Analysis of the complexation constants and the mobilities of the analyte-CD complexes at pH 9.5 in the presence of TMA-β-CD and β-CD revealed identical chiral recognition of both CDs towards Ala-Phe, Ala-Tyr, and Asp-PheOMe. Despite identical enantiomer migration order compared to the other peptides, TMA-β-CD displayed opposite chiral recognition towards the enantiomers of Ala-Trp. In contrast to the other investigated peptides, the enantiomer migration order of Ala-Trp was determined by the mobility of the CD-peptide complex which was higher in the case of the stronger complexed enantiomer.
QSPR Analysis of Solvent Effect on Selectivity of 18-Crown-6 between Nd 3+ and Eu 3+ Ions: a Monte Carlo Simulation Study

We have investigated the solvent effects on Alog K s (the difference of stability constant of binding) and the different free energies of binding of Nd 3+ and Eu 3+ ions to 18-crown-6, i.e., the selectivity of Nd 3+ and Eu 3+ ions to 18-crown-6 using a Monte Carlo simulation of statistical perturbation theory (SPT) in diverse solvents. The stability constant (Alog K s ) of binding of Nd 3+ and Eu 3+ ions to 18-crown-6, in CH 3 OH was calculated in this study as -1.06 agrees well with the different experimental results of -0.44∼-0.6, respectively. We have reported here the quantitative solvent-polarity relationships (QSPR) studied on the solvent effects the relative free energies of binding of Nd 3+ and Eu 3+ ions to 18-crown-6. From the calculated coefficients of QSPR, we have noted that solvent polarity (E T ) and Kamlet -Taft's solvatochromic parameters (β) dominate the differences in relative solvation Gibbs free energies of Nd 3+ and Eu 3+ ions but basicity (Bj) dominates the negative values in differences in the stability constant (Alog K s ) as well as the relative free energies of binding of Nd 3+ and Eu 3+ ions to 18-crown-6 and acidity (Aj) dominates the positive values in differences in the stability constant (Alog K s ) as well as the relative free energies of binding of Nd 3+ and Eu 3+ ions to 18-crown-6.
Detection of nucleotide bases in ancient seeds using gas chromatography/mass spectrometry and gas chromatography/mass spectrometry/mass spectrometry

Nucleic acid extracts from 1400-year-old radish seeds recovered from excavations at Qasr Ibrim, Upper Egypt, have been analysed by gas chromatography/mass spectrometry and gas chromatography/mass spectrometry/mass spectrometry. tert-Butyldimethyisilyl derivatives of the purine and pyrimidine bases were prepared, after treatment of the nucleic acid extracts with concentrated formic acid. Under electron ionization these derivatives yield prominent [M–57]+ ions that were found to be of value for use in analyses employing selected-ion monitoring and product-ion studies. These two techniques were used in the sensitive and selective detection of nucieotide bases in crude extracts of ancient seeds. The results obtained were supported by complementary analyses of hydrolysates of ancient nucleic acids and authentic bases by means of retention time and spectral comparisons. This work demonstrates for the first time that mass spectrometry can be used in the direct chemical examination of nucleotide bases in ancient materials. This analytical approach is currently being used to address questions regarding the possible chemical (diagenetic) changes occurring in the nucleic acids of ancient biological material.