Miracle-dz/UniFAR-FTUs huggingface dataset:
Sphericity Optimization of Calcium Alginate Gel Beads and the Effects of Processing Conditions on Their Physical Properties

In this study, the sphericity of calcium alginate gel beads was optimized using response surface methodology. The optimum conditions for bead sphericity were a concentration of 2.24% sodium alginate, a flow rate of 0.059 mL/sec for the sodium alginate solution, and a 459 rpm rotation for the calcium chloride solution. The predicted and experimental bead sphericities under the optimum conditions were 94.5 and 96.7%, respectively, showing close agreement. We also investigated the processing condition effects for the physical properties of the optimized calcium alginate gel beads. Immersion in hot water slightly decreased bead size and rupture strength. NaCl treatment increased bead size and decreased rupture strength. While the pH of the calcium chloride solution had little effect on bead sphericity, the bead sizes and gel strengths decreased with longer times in each pH solution. The beads coated with pectin and glucomannan showed no significant changes in sphericity, but their sizes decreased with time. The coated beads showed higher rupture strengths than the uncoated beads.
Photooxidation of carbonyl sulfide in the presence of the typical oxides in atmospheric aerosol

Photooxidation of carbonyl sulfide (COS) under UV irradiation and the role of the oxides such as SiO 2 , Al 2 O 3 and Fe 2 O 3 were investigated by in situ FTIR in a long optical path cell. The major products were identified as SO 2 and CO 2 by means of IR spectra and GC-MS. SO 2 was partially oxidized into SO 4 2- on the surface of the oxides and interior wall of the reactor, which was determined by XPS. The photooxidation is pseudo first order with respect to COS, and the apparent rate constant is approximately 9.30×10 -4 ·s -1 . SiO 2 and Al 2 O 3 promote the photooxidation of COS significantly, but Fe 2 O 3 has no obvious influence on the reaction. The reaction rates in the presence of the oxides or not, rank as: UV+SiO 2 >UV+Al 2 O 3 >UV, UV+Fe 2 O 3 . The potentiality of the oxides for promoting the photooxidation of COS implicates that the aerosol particles may contribute to the photooxidation of COS in the atmosphere.
Composition of RF-sputtered refractory compounds determined by X-ray photoelectron spectroscopy

rf‐sputtered coatings of CrB2, MoSi2, Mo2C, TiC, and MoS2 were examined by x‐ray photoelectron spectroscopy (XPS). Data on stoichiometry, impurity content, and chemical bonding were obtained. The influences of sputtering target history, deposition time, rf power level, and substrate bias were studied. Significant deviations from stoichiometry and high oxide levels were related to target outgassing. The effect of substrate bias depended on the particular coating material studied.
ALGUNAS APLICACIONES DEL ÁCIDO POLI-L-LÁCTICO

En este artículo se describen, de manera resumida, algunos trabajos realizados en el laboratorio de polímeros de la Universidad del Valle sobre ácido polil-L-láctico (PLLA), un compuesto biodegradable. Específicamente se describe la síntesis de PLLA de alto y bajo peso molecular y su aplicación en la fabricación de dispositivos o de andamios (scaffolds) para el crecimiento de células óseas, ya sea en forma de bloques blandos, películas, bloques porosos y tornillos. La caracterización de los diferentes materiales se realizó por espectroscopia (resonancia magnética, RMN, e infrarrojo, IR), análisis térmico, y microscopía, por determinación de sus pesos moleculares (viscosimetría, cromatografía) y de sus propiedades mecánicas. Los implantes, las pruebas de biocompatibilidad y de crecimiento celular se realizaron en conejos y se evaluaron de forma macroscópica, y mediante pruebas histológicas.
DETERMINACIÓN DE COCIENTES CRÍTICOS K/P EN PRADERAS A PARTIR DE UN ENSAYO MULTIFACTORIAL DE FERTILIZACIÓN

An investigation was eonducted to assess the value of herbage nutrient ratios for diagnosing nutritional status of pasture plants, and to determine the K/P ratio whieh corresponded to good nutritional balance between these elements. A P x K x N factorial trial with 6 rates of P, 3 rates of K and 2 rates of N was established on a newly-sown pasture of white clover and ryegrass. Herbage was cut 4 times in the following year and measurements of DM production and ehemical composition of white clover and total herbage were made. For each treatment, potential responses to P and K (PRP and PR]<) were calculated, these being the maximum additional yields which have been obtained with higher applications of P alone or K alone, respectively. Values for (PRP - PR|<) were plotted against K/P ratios in white clover and total herbage. White clover K/P ratios greater than 5.4 were nearly always associated with positive values of (PRP - PR]<) in total herbage (i.e. P more deficient than K), and vice versa. Thus a K/P ratio of 5.4 in white clover was taken to indicate ideal nutritional balance of K and P in the pasture and was described as the critical K/P ratio. K/P ratios in total herbage also differentiated well between treatments more deficient in P and those more deficient in K, but the critical level was much higher, due apparently to luxury uptake of K in ryegrass. It was concluded that the K/P ratio in the white clover component was a useful indicator of nutritional balance in a pasture; and it was suggested that the method developed for deriving the critical K/P ratio could be used to derive DRIS ratio norms when the conventional DRIS method was not applicable.
Quantitative Determination of Sodium Metatungstate Speciation by 183W N.M.R. Spectroscopy

The speciation and equilibria of sodium metatungstate, Na6[H2W12O40], has been determined by a combination of 183W n.m. r. spectroscopy and gravimetry over the p[H] range 4.5–10.0. The use of n.m. r. spectroscopy allowed the direct observation of polytungstate anions in aqueous solution and high concentration (0.25 mol l–1). Sodium metatungstate, with the progressive addition of base, was found to decompose to paratungstate A, [W7O24]6–. Paratungstate A then slowly converted to paratungstate B, [H2W12O42]10–. The kinetics of equilibrium was found to be slow, requiring up to 8 months to stabilize. With the addition of further base paratungstate B decomposed to orthotungstate, WO42–. Logarithmic constants (logK) for these transformations were determined as 195, 20 and 118, respectively. The solubility product for sodium paratungstate B was determined to be 6.89 ( 0.80) 10–6.
Changes in elemental composition, molecular weight and 1H NMR spectra of the water-extractable hydrophobic acid fraction in Cambisol with season and soil depth

Abstract The chemical composition of the hydrophobic acid fraction, which is adsorbed to XAD-8 resin at low pH and desorbed with high pH solution, of water-extractable organic matter in soil probably influences its environmental role and, therefore, it is important to recognize the differences in its chemical composition with season and soil horizon. Hydrophobic acid fractions were collected seasonally in 2004 from Oi, Oe/Oa, A and B horizons of Cambisol and were investigated using elemental analysis, high-performance size exclusion chromatography and 1H nuclear magnetic resonance (NMR) spectroscopy. Atomic ratios of H/C and O/C decreased with increasing soil depth in winter and summer, suggesting that the hydrophobic acid fraction from lower mineral horizons had lower saturated bond content and carbohydrate content than the fractions from upper organic horizons. Based on high-performance size exclusion chromatography, the molecular weight at peak maximum of the hydrophobic acid fraction decreased significantly with increasing soil depth. The 1H NMR spectra of the hydrophobic acid fraction showed remarkable changes. The signal intensities of carbohydrate protons (δ 3.0–4.3 p.p.m.) in the hydrophobic acid fraction from organic horizons decreased from winter to summer and increased in autumn, while the signal of aliphatic protons (δ 0–3.0 p.p.m.) increased and decreased. In all seasons of the year, the signal intensities of carbohydrate protons were greater in organic horizons and decreased significantly with depth in mineral soil, but the signal for aliphatic protons increased. Our results demonstrate that season and soil depth influence the chemical composition of the hydrophobic acid fraction of water-extractable organic matter.
Ultrasound as a Pretreatment Method to Improve Drying Kinetics and Sensory Properties of Dried Apple

The effect of ultrasound pretreatment on drying kinetics and physical properties as color and rehydration rate of dried apple slices was investigated. Apple samples var. Idared were submitted to ultrasonic treatment using 21 and 35 kHz for 30 min in an ultrasound bath securing sound intensity of 3 and 4 W/cm2, respectively. After pretreatment, the material was dried in a convective oven at 70C and at an air velocity of 2 m/s. The sonication reduced drying time by 13–17% in comparison with the untreated sample. Ultrasound treatment changed the color of apples tissue by decreasing the value of a* parameter and increasing the dried material lightness, chromaticity and the value of b* coefficient. Moreover, obtained results showed that there was a significant effect of pretreatment on rehydration properties as compared with untreated apple tissue. Practical Applications The most energy-consuming processes existing in the food technologies are the processes based on heat and/or mass transfer, for instance drying. Thus, a lot of attention is paid by researchers to conserve the energy and minimally change the physicochemical properties of food, which shape its quality. Additionally, increasing growth of consumers' expectations and their nutritional knowledge stimulate to seek some new solutions even more. Aforementioned is a reason why nonthermal technologies as ultrasound seem to be the one of the most interesting propositions.
Excitation energy effects on the fluorescence quantum yield in solution. Deactivation pathways for aromatic amines

The dependence of the fluorescence quantum yield, QF, on the energy of the exciting light was examined for a number of aromatic amines (aniline, N,N-dimethylaniline, 2-phenylethylamine, etc.) in various polar and non-polar solvents down to 200 nm. QF of aniline is constant throughout the first absorption system but decreases when the excitation reaches the second band. This effect is most pronounced in hydrocarbon solutions but small in polar solvents capable of forming hydrogen bonds, with the only exception being water. For N,N-dimethylaniline a wavelength dependence of QF is observed only in aqueous solutions. Concomitant to the QF decrease the H2 evolution in hydrocarbons and electron ejection in water increase. These effects are also observed for solutions of 2-phenylethylamine and are explained by the formation of weak intramolecular complexes. A further pathway, characteristic of the benzoic ring, is assumed to be responsible for the wavelength dependence of protonated anilines. The derived deactivation pattern is of general validity for simple polar aromatics.
Essential Oil Composition of Leaves, Fruits and Resin of Protium heptaphyllum (Aubl.) March.

Abstract Essential oils from the leaves, fruit and resin of Protium heptaphyllum were analyzed by GC/MS from a sample collected in Crato-Ceara, Brazil. The major constituents identified in the leaves were mono and sesquiterpenes such as myrcene (18.6%), β-caryophyllene (18.5%) whereas oils from resin and fruit contained mainly monoterpenes such as α-pinene (10.5%), limonene (16.9%), α-phellandrene (16.7%), and terpinolene (28.5%) in the resin oil, and α-pinene (71.2%) in the fruit oil
Lithium insertion processes of orthorhombic Na{sub x}MnO{sub 2}-based electrode materials

Electrochemical, thermal, and structural characterization of lithium insertion processes into orthorhombic Na{sub x}MnO{sub 2}-based materials is presented. Chimie douce oxidation, reduction, and/or exchange reactions of the precursor Na{sub 0.44}MnO{sub 2} can be used to prepare high capacity (180 mAh/g), high potential compounds for use in secondary lithium batteries. Lithiated Na{sub x}MnO{sub 2} is quite stable; formation of spinel phases occurs only under conditions of prolonged severe abuse during cycling in electrochemical cells, or upon heating to 500 C. The lithium-ion intercalation process is considerably more complex than that for sodium ions; features are seen in the electrochemical potential-step experiments that may be attributed to several phase transitions. These results are interpreted in terms of the unusual structure, and implications for future use of these materials in lithium batteries are discussed.
An experimental study on the evolution of aggregate structure in coals of different ranks by in situ X-ray diffractometry

Coal samples of different ranks were selected based on geological ages and regions to investigate their thermal evolution in aggregate structure using in situ X-ray diffraction (XRD) spectroscopy. Samples were heated at a rate of 10 °C min−1 in the range of 25–900 °C. The XRD profiles of the coal samples displayed an evident decrease in intensity of peak at 20° (λ-band), which suggests the decomposition of oxygen-containing functional groups in the coal matrix at higher temperatures. In contrast, the peak at 26° (so-called G-band) became sharper and shifted to higher angles, which suggests a more ordered crystallite structure of coal with increasing heating temperature. Note that the integrally diffracted intensity of these two bands weakened intensely above 400 °C, which suggests that the coal aggregate structure may be loosened due to the depolymerization of the carbonaceous matrix in coal. The primary phase of weight loss for the low-rank coals took place in the range of 300–500 °C, but the high-rank coals had an obvious second pyrolysis reaction above 500 °C. Moreover, this study shows that the heating temperature effect plays a key role in the evolution of the interlayer spacing of the crystalline structure (d002) and height of the aromatic layers (Lc), whereas the diameter of the aromatic layers (La) is more dependent on coal ranks rather than heating temperature.
Laser induced fluorescence of ground state hydrogen atoms at nozzle exit of an arcjet thruster

Abstract : We report the first observation of a two-photon laser-induced fluorescence (LIF) technique in an arcjet plume. Ground state hydrogen atoms are detected with high spatial resolution near the thruster nozzle exit. Number density, axial and radial velocity, and translational temperature distributions are obtained in the expansion plume of a 1 kW arcjet operating on hydrogen propellant. Comparison of the ground state properties with previously measured excited state hydrogen data and recent computational data is discussed.
Micromixing and dispersion in chlorine contact chambers

Abstract Prior workers have analyzed the phenomenon of partial backmixing in chlorine contact chambers and have assumed complete segregation. In this paper, the unified analysis of macro‐ and micro‐ mixing in such systems is presented. Although, qualitatively, the effect of nonideal macromixing is similar to that previously reported, it is found that micromixing, particularly when high degrees of inactiv‐ation are desired, may be an important factor to consider in process design.
Evaluation of film-forming potential of a natural gum

Films were prepared using 5 parts of 10% w/w of mucilage of gum of Moringa oleifera with different proportions of plasticizers: polyethylene glycol (PEG 400) (0.1, 0.15, 0.2, and 0.3), glycerin (0.15), and propylene glycol (0.2). The films were casted on glass plates and dried under controlled evaporation. Films prepared with 0.15, 0.2 part of PEG 400; 0.15 part of glycerin and propylene glycol showed satisfactory drying after 24 h. They were evaluated for following parameters water uptake, tensile strength, folding endurance, and water vapor transmission rate. The results obtained are comparable with films made from other polymers, and the gum can be used for preparing polymeric drug delivery systems and as film coating agent.
Activation volume of crystallization and effects of pressure on the three-dimensional nucleation rate of glucose isomerase

The activation volume, Δ V ‡, of the solute incorporation process at the kink site of a glucose isomerase (GI) crystal was estimated using the pressure dependency of the step kinetic coefficient, βstep, and the three-dimensional nucleation rates J of GI crystals were analyzed using classical nucleation theory. Δ V ‡ took a negative value. The sticking parameter, s, for the addition of a GI tetramer to a critical nucleus drastically increased with increasing pressure. This was probably due to the decrease in the activation energy needed for the addition of the GI tetramer.
Improved Sludge Gasification by Two‐Phase Anaerobic Digestion

The objectives of this research are to study the relative efficacies of two‐phase and single‐stage, high‐rate anaerobic sludge digestion at mesophilic and thermophilic temperatures at several levels of hydraulic residence time (HRT), organic loading rate, and feed consistency. In addition, the effects of pH, temperature, and HRT on acid‐phase digestion are studied. Data from continuous‐flow digestion studies showed that the two‐phase process is better than single‐stage digestion under all test conditions when compared on the bases of gas yield and production rate, reductions of volatile solids, carbohydratelipid‐protein conversions, buffer‐capacity, and unconverted volatile acids in the effluent. A mesophilic two‐phase system exhibits about the same methane yield and solids reduction at a 3‐day HRT as those of single‐stage high‐rate digestion at 15‐ and 17‐day HRT's. The enhanced stability of two‐phase digestion relative to single‐stage digestion increases as the system loading and hydraulic dilution rate.
Concentration of Ciprofloxacin in Brazilian Hospital Effluent and Preliminary Risk Assessment: A Case Study

This study was carried out to evaluate the occurrence of the fluoroquinolone antimicrobial agent ciprofloxacin (CIP) in the effluent of the Hospital of the Federal University of Santa Maria (HUSM). Measured environmental concentrations (MECs) of CIP in the hospital wastewater, both before (P1) and after (P2) cesspit/filter system treatment (CFTS), were determined by means of solid phase extraction and reversed-phase liquid chromatography with fluorescence detection (LC-FLD) and reversed-phase liquid chromatography with mass spectrometric detection (LC-MS/MS). The MECs (n = 7 daily composed samples) were 19 to 155 μg L -1 (average: 54 ± 21 μg L -1 ) and 32 to 99 μg L -1 (average: 65 ± 45 μg L -1 ) in P1 and P2, respectively. No relevant removal was observed from P1 to P2. In a worst case scenario, the final effluent was regarded as MECs of surface water. These MECs were generally 5 to 20,000-fold higher than what was previously known. If the present data is drawn on to form a model of the situation in developing countries, the picture provides a first rough indication that the environmental risk associated with the use and emission of pharmaceuticals into the environment in developing countries might be higher than in developed countries.
The transcription of nitrate transporters in upland rice varieties with contrasting nitrate-uptake kinetics

Nitrogen (N) is one of the mineral elements required in the greatest quantity by plants and the one that most often limits productivity. In addition, the use of N fertilizers may be associated with environmental damage. The rational use of N fertilizers can be achieved by both better management techniques and the use of plant varieties that are more efficient in N use. Two rice (Oryza sativa L.) varieties (Piaui and IAC-47) with contrasting nitrate-uptake kinetics (Km and Vmax) were studied through the evaluation of the transcription of genes encoding for the high and lowaffinity nitrate transporters (NRT2 and NRT1, respectively) and NAR2 partner protein needed for NRT2 functional nitrate transporter, as well as the assessment of N soluble fractions (amino-N, NO 3 -N, NH 4 -N) and soluble sugars. The Piaui variety presented higher transcription of the OsNAR2.1, OsNRT2.1, OsNRT2.2 and OsNRT2.3a and accumulated more NO 3 in the shoots, sheath and roots when cultivated under low supply of nitrate. OsNRT2.1, OsNRT2.2 and OsNAR2.1 transcription correlated with nitrate concentration in roots, while OsNRT2.1, OsNRT2.2 and OsNRT2.3a correlated with nitrate concentration in leaves. The results of this study indicate that the Piaui variety is adapted to conditions of low natural fertility and seasonal nitrate flux, characteristics of the humid tropics. There is evidence that a portion of this adaptation process maybe due to the differential expression of genes encoding for the high-affinity nitrate transport proteins, synchronizing plant metabolism with nitrate availability in the soil.
Reversible Addition Fragmentation Chain Transfer (RAFT) Polymerization of Methyl Acrylate: Detailed Structural Investigation via Coupled Size Exclusion Chromatography−Electrospray Ionization Mass Spectrometry (SEC−ESI-MS)

The on-line coupling of size exclusion chromatography (SEC) with electrospray ionization mass spectrometry (ESI-MS) was applied to study the polymeric product spectrum generated by the (strongly rate retarded) 2,2‘-azobisisobutyronitrile (AIBN) and 1,1‘-azobis(cyclohexanecarbonitrile) (ACHCN) initiated, cumyl dithiobenzoate (CDB) mediated methyl acrylate (MA) polymerization in detail. Products corresponding to the polymeric reversible addition fragmentation chain transfer (RAFT) agent and the combination and disproportionation termination products (with both cumyl, cyanocyclohexyl, and cyanoisopropyl end groups) along with a product stream arising from an oxidation process of the polymeric RAFT agent yielding sulfines and thioesters could be clearly identified. Termination products associated with the intermediate radical, that is, three- or four-armed star polymers, were not present. There is a degree of ambiguity over the disproportionation product of the macroRAFT radical. The experiments suggest that .