Miracle-dz/UniFAR-FTUs huggingface dataset:
Iodide Ion Sensor for Indirect Determination of As (III) in Water

A simple, low cost and portable iodide sensor for the indirect determination of As(III) has been developed from the polycrystalline material obtained by co-precipitation of silver sulphide and silver iodide from aqueous solution. The Ag2S-AgI sensor was found to behave well up to the iodide concentration of 1×10-6 M with a Nernstian slope 57.5 mV per decade change in concentration. The selectivity coefficient of sensor containing iodide ion in the presence of Br- and Cl- ions was found to be 1.77 × 10-2 and 7.94 × 10-3, respectively indicating that these ions do not interfere in the response of iodide sensor to iodide ion. The electrode was successfully used for the direct determination of iodide and indirect determination of As(III) by titrating with cerric ammonium sulphate at pH 2. The results obtained from this method are comparable to the existing methods for the estimation of As(III).
Total reflection high-energy positron diffraction: An ideal diffraction technique for surface structure analysis

It is shown that the reflection high-energy positron diffraction (RHEPD) pattern from a Si(111)-(7 × 7) reconstructed surface for the total reflection condition, that is, the total reflection high-energy positron diffraction (TRHEPD) pattern, does not contain contributions from atoms in the bulk. Now, a method of observing the diffraction pattern formed only by the atoms on the topmost surface by a straightforward measurement of a bulk sample is available.
Influence of chemical characteristics of beef inside and outside semimembranosus on color traits

The influence of prerigor temperature and pH on muscle chemistry of the inside semimembranosus (ISM) and outside semimembranosus (OSM) in relation to initial color and color uniformity and stability was investigated. Cold-boned ISM had a slower (p < 0.05) chill rate; faster (p < 0.05) pH decline; higher (p < 0.05) transmission values; and less (p < 0.05) metmyoglobin reducing ability, oxygen consumption, water holding capacity and color stability than the OSM. Cold-boned steaks were 2-toned in color and visually unacceptable at d 3 of display. Hot-boned ISM and OSM chilled at the same rate and had similar pH declines, similar chemical characteristics and uniform stable color for 5 d of display. Chilling beef ISM faster should produce uniform stable color.
GSPROJECTS - Ambiente para Simulação da Gestão de Projetos de Software

The use of games for education and training has a high power of attraction compared to other forms of learning. Featured games for this purpose are classified as serious games, as they associate specific content to play activities providing engagement and significant results when properly modeled. This article presents the proposal of GSPROJECTS, a serious games aimed at the sustainable management of projects using real-world scenarios in which students of the Information Technology are causing to use their knowledge in driving and problem solving within a project. The GSPROJECTS stimulates cognitive functions associated with the perception and learning, allowing the teacher to edit the challenges through the questionnaire module, and the game to adapt to different curricula of undergraduate courses in Computer and Information Technology area.
Near-Infrared Raman Spectrometer Systems for Human Tissue Studies

We have built two types of instruments for near-infrared Raman spectroscopy studies of human tissues, one for laboratory measurements and one for clinical use. The laboratory systems are designed to collect the highest quality spectra possible and allow different excitation/collection wavelengths to be studied. The clinical systems are designed to collect spectra via optical fibers within a few seconds and to be mobile and hospital-compatible. These systems are capable of detecting weak near-infrared Raman bands hidden in large background signals. Calibration and background subtraction procedures are described, and system performance is evaluated.
Charge Transport in 1-D Nanostructured CdS Dye Sensitized Solar Cell

Charge transport in eosin yellow sensitized CdS 1-D nanostructures is studied. Direct conduction pathway for electron transport in nanowires enhances in CdS nanowires compared to nanorods and nanoparticles. characterization of nanowires results in improved efficiency of 0.184% due to fewer interparticle connections. Increase in is observed by coating CdS 1-D nanostructures on TiO2 substrate which reduces rate of recombination and photocorrosive nature of CdS photoanodes. Enhancement in efficiency up to 0.501% is achieved for CdS 1-D nanostructures DSSCs on TiO2 substrate.
The Effect of Extrusion Conditions on the Physical and Functional Properties of Millet – Bambara Groundnut Based Fura

Studies were conducted on the Extrusion of fura from pearl millet and Bambara groundnut applying the Response Surface Methodology (RSM) consisting of 15 design points, using a single screw laboratory Brabendar extruder. The effects of three extrusion variables (feed composition – percentage Bambara groundnut to pearl millet, feed moisture content and screw speed) on some physical properties (bulk density, ‘BD’ expansion ratio, ‘ER’, mass flow rate, ‘MFR’, average residence time, ‘ART’ and specific mechanical energy, ‘SME’) and some functional properties (water absorption index, ‘WAI’, water solubility index, ‘WSI’ and viscosity); of fura extrudates were evaluated using response surface method (RSM). Models were developed and appropriate statistical analysis adopted to test the adequacy of the models. Linear, quadratic and interaction regression and coefficient terms and coefficients of determinants were computed to test the adequacy of the models and response surface plots were also produced from the equation and model. The linear, quadratic and interaction terms were significant (p 0.05), however the linear and quadratic terms were significant (p<0.05). The error analysis showed that lack of fit was not significant (p<0.05) for ART. The regression models for data were significant (p<0.05) with satisfactory coefficients R2 of 0.87, 0.87 and 0.92 for ART, MFR and SME respectively indicating a good fit. The coefficients of variation (CV) were less than <10%. Extrusion conditions affected the ER significantly (p<0.05) by linear and interaction terms. The BD was influenced by only the linear term (p<0.05). The R2 were 0.82 and 0.84 for ER and BD respectively, suggesting good fit. Linear, quadratic and interaction terms affected WAI. However only linear and quadratic terms indicated influence on the WSI. The R2 were 0.93 and 0.84 for WAI and WSI respectively. The samples shows that, linear, quadratic and interaction terms influenced viscosity significantly (p<0.05) with the linear term showing more effect and the R2 was 0.88 for viscosity, The lysine content (result not shown) of extrudates tremendously increased as expected as a result of inclusion of Bambara groundnut. The essential amino acids (result not shown) were present in adequate levels if compared with the recommended values of FAO/WHO (1973).
Plasmon-enhanced dye-sensitized solar cells using SiO2 spheres decorated with tightly assembled silver nanoparticles

SiO2 spheres decorated with tightly assembled silver nanoparticles were incorporated into the photoanode of a dye-sensitized solar cell. Localized surface plasmon resonance from the assembled Ag nanoparticles increased the light absorption throughout the wide visible light range. This plasmon-enhanced light absorption resulted in a significant improvement in the device performance.
Effect of shelf conditions on the phenolic fraction and oxidation indices of monovarietal extra virgin olive oil from cv. ‘Taggiasca’

The quality of monovarietal extra virgin olive oil from cv. ‘Taggiasca’ is influenced by many factors that have impact on shelf-life as well as on sensory and healthy properties of the product. The aim of the work was to recreate the conditions similar to those in consumer sales point (conditions of “shelf”), maintaining the olive oil packaged in dark-green bottles at room temperature (between 18 and 25 °C) under artificial light and away from heat sources, monitoring the oils up to 12 months from bottling with quarterly sampling for the main chemical, physico-chemical, and sensory parameters related to the quality. After one year of storage, an organoleptic alteration with reduction of the attributes ‘fruity’, ‘pungent’, and ‘bitter’, as well as the occurrence of ‘rancid’ defect, was observed. This alteration was found to be accompanied by a decrease in phenolic substances and tocopherols and an increase in primary and secondary oxidation products. The composition of the volatile fraction showed a slight.
Bending rigidity of stiff polyelectrolyte chains: A single chain and a bundle of multichains

We study the bending rigidity of highly charged stiff polyelectrolytes, for both a single chain and many chains forming a bundle. A theory is developed to account for the interplay between competitive binding of counterions and charge correlations in softening the polyelectrolyte (PE) chains. The presence of even a small concentration of multivalent counterions leads to a dramatic reduction in the bending rigidity of the chains that are nominally stiffened by the repulsion between their backbone charges. The variation of the bending rigidity as a function of f 0 , the fraction of charged monomers on the chain, does not exhibit simple scaling behavior; it grows with increasing f 0 below a critical value of f 0 . Beyond the critical value, however, the chain becomes softer as f 0 increases. The bending rigidity also exhibits intriguing dependence on the concentration of multivalent counterion n 2 ; for highly charged PEs, the bending rigidity decreases as n 2 increases from zero, while it increases with increasing n 2 beyond a certain value of n 2 . When polyelectrolyte chains form a N-loop condensate (e.g., a toroidal bundle formed by N turns (winds) of the chain), the interloop coupling further softens the condensate, resulting in the bending free energy of the condensate that scales as N for large N.
A review of charge transport and recombination in polymer/fullerene organic solar cells

The charge carrier transport and recombination in two types of thermally treated bulk‐heterojunction solar cells is reviewed: in regioregular poly(3‐hexylthiophene) (RRP3HT) mixed with 1‐(3‐methoxycarbonyl)propyl‐1‐phenyl‐[6,6]‐methanofullerene (PCBM) and in the blend of poly[2‐methoxy‐5‐(3,7‐dimethyloctyloxy)‐phenylene vinylene] (MDMO‐PPV) mixed with PCBM. The charge carrier mobility and bimolecular recombination coefficient have been comparatively studied by using various techniques including Time‐of‐Flight (ToF), Charge Extraction by Linearly Increasing Voltage (CELIV), Double Injection (DI) transients, Current–Voltage (I–V) technique. It was found that the carrier mobility is at least an order of magnitude higher in RRP3HT/PCBM blends compared to MDMO‐PPV/PCBM. Moreover, all used techniques demonstrate a heavily reduced charge carrier recombination in RRP3HT/PCBM films compared to Langevin‐type carrier bimolecular recombination in MDMO‐PPV/PCBM blends. As a result of long carrier lifetimes the formation of high carrier concentration plasma in RRP3HT/PCBM blends is demonstrated and plasma extraction methods were used to directly estimate the charge carrier mobility and bimolecular recombination coefficients simultaneously. A weak dependence of bimolecular recombination coefficient on the applied electric field and temperature demonstrates that carrier recombination is not dominated by charge carrier mobility (Langevin‐type recombination) in RRP3HT/PCBM blends. Furthermore, we found from CELIV techniques that electron mobility in RRP3HT/PCBM blends is independent on relaxation time in the experimental time window (approx. hundreds of microseconds to tens of milliseconds). This reduced carrier bimolecular recombination in RRP3HT/PCBM blends implies that the much longer carrier lifetimes can be reached at the same concentrations which finally results in higher photocurrent and larger power conversion efficiency of RRP3HT/PCBM solar cells. Copyright © 2007 John Wiley & Sons, Ltd.
Identifying Potato Varieties Using Machine Vision and Artificial Neural Networks

The objective of this study is to develop a method for identifying and discriminating 10 potato varieties by combining machine vision and artificial neural network methods. The potato varieties include Agria, Savalan, Florida, Fontaneh, Natasha, Verona, Karso, Elody, Satina, and Emrad. A total number of 72 characteristic parameters specifying color, textural, and morphological features are found among these varieties. By using principal component analysis, 16 principal features are selected for identifying and discriminating potato varieties. The data obtained from image processing were classified using linear discriminant analysis and non-linear artificial neural network method. The accuracy of discriminant analysis were 73.3, 93.3, 73.3, 40, 73.3, 73.3, 66.7, 80, 40, and 53.3%, respectively, for the varieties used in this study. The classification accuracy was improved by 100% for all the varieties using neural network analysis and the correct classification ratio was 100% using this method. It is revealed from the results that machine vision technique and neural network analysis could identify potato varieties with acceptable accuracy.
Impact of water film thickness on kinetic rate of mixed hydrate formation during injection of CO2 into CH4 hydrate

In this work, nonequilibrium thermodynamics and phase field theory (PFT) has been applied to study the kinetics of phase transitions associated with CO2 injection into systems containing CH4 hydrate, free CH4 gas, and varying amounts of liquid water. The CH4 hydrate was converted into either pure CO2 or mixed CO2CH4 hydrate to investigate the impact of two primary mechanisms governing the relevant phase transitions: solid-state mass transport through hydrate and heat transfer away from the newly formed CO2 hydrate. Experimentally proven dependence of kinetic conversion rate on the amount of available free pore water was investigated and successfully reproduced in our model systems. It was found that rate of conversion was directly proportional to the amount of liquid water initially surrounding the hydrate. When all of the liquid has been converted into either CO2 or mixed CO2CH4 hydrate, a much slower solid-state mass transport becomes the dominant mechanism. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3944–3957, 2015
Isotopic dilution determination of emerging flame retardants in marine sediments by HPLC-APCI-MS/MS

Due to their extensive use and wide range of applications, the occurrence of flame retardants in the environment is still a hot issue of environmental interest. An HPLC-APCI-MS/MS method was developed for the simultaneous determination of selected emerging flame retardants in marine sediments. Target flame retardants include α, β, γ-diastereoisomers of hexabromocyclododecane (HBCD), tetrabromobisphenol-A (TBBP-A), anti- and syn-isomers of dechlorane plus (DP) and two novel flame retardants, decabromodiphenylethane (DBDPE) and 2-bis(2,4,6-tribromophenoxy) ethane (BTBPE). The method developed in this work is based on pressurized liquid extraction followed by cleaning of the sample with a silica gel column and then instrumental analysis. The instrumental detection limits ranged between 0.25 ng mL−1 for TBBP-A and 9 ng mL−1 for syn-DP, and the limits of quantification ranged between 0.035 ng g−1 for BTBPE and 0.35 ng g−1 for syn-DP. Accurate quantification of the analytes was achieved by the isotopic dilution technique, which corrects for analyte losses, matrix effects and instrumental fluctuation. The method described here was further applied to South Korean coastal sediment samples. All of the target flame retardants were detected in the sediment samples except for DPs and DBDPE. The detected flame retardants ranged in concentration from 0.06 ng g−1 dw for TBBP-A to 1.43 ng g−1 dw for γ-HBCD.
Field chlorophyll measurements for evaluation of corn nitrogen status 1

Abstract An experiment was conducted on Norfolk sandy loam soil (Fine‐loamy, siliceous, thermic Typic Kandiudults) during two years to determine the feasibility of using field chlorophyll measurements for evaluation of corn (Zea mays L.) N status. Nitrogen was applied at rates of 56, 112, 168, 224, 280 and 336 kg ha‐1 to establish a range of corn chlorophyll levels, tissue N concentrations, and grain yields. At the V10 and midsilk stages of growth, field chlorophyll measurements were taken with a hand‐held chlorophyll meter (SPAD‐502 Chlorophyll Meter, Minolta Camera Co., Ltd., Japan)3 and tissue N was determined. A typical curvilinear grain yield response to N fertilizer was observed both years; maximum agronomic yields were obtained with 227 and 242 kg N ha1, respectively, in 1990 and 1991. Tissue N concentrations at V10 and midsiik were a good predictor of grain yield. Field chlorophyll measurements were highly correlated with tissue N concentrations at both growth stages during both years of the study.
Molecular Iodine–Catalyzed, Mild, Effective, Ecofriendly, Microwave-Assisted, One-Pot Synthesis of 5-Arylmethylidene-2-phenyloxazol-4-ones (Azalactones) Under Solvent-Free Conditions

Fourteen azalactones have been synthesized in excellent yields under solvent-free conditions by heating an aldehyde, hippuric acid, and acetic anhydride in the presence of molecular iodine as a catalyst in a microwave oven. The short reaction time, cleaner reaction, and easy workup make this protocol practical and economically attractive.
Structural Investigations on Poly(4-hydroxy-L-proline). 1. Theoretical Studies

Model building studies on poly(hydroxypro1ine) indicate that in addition to the well-known helical structure of form A, a left-handed helical structure with trans peptide units and with h = 2.86 A and n = 2.67 (i.e., 8 residues in 3 turns) is also possible. In this structure which is shown to be in agreement with X-ray data of the form B in the next paper, the y-hydroxyl group of an (i + 1)th Hyp residue is hydrogen bonded to the carbonyl oxygen of an (i - 1)th residue. The possibility of a structure with cis peptide units is ruled out. It is shown that both forms A and B are equally favorable from considerations of intramolecular energies. Since form B is further stabilized by intrachain hydrogen bonds, we believe that this is likely to be the ordered conformation for poly(hydroxypro1ine) in water.
Simple theory of steam oxidation of AlAs

Kinetics of AlAs steam oxidation process is investigated theoretically in cylindrically symmetric mesa structures. Under the assumption of a steady-state process, compact analytical formulae are obtained for time evolution of the oxidation front and for the oxidation rate. Values of main oxidation process parameters are extracted from existing experimental data for T = 350 °C and the layer thickness d = 250 nm. The oxidation rate is found to first decrease from its initial value of B/A and remain almost constant for a large range of intermediate sizes of unoxidized region. When the unoxidized region becomes very small, a rapid increase in this rate up to the value of B/[A(1-β)] is predicted. This renders the process control of fabricating miniature oxide apertures with diameters < 2 μm extremely difficult. Comparison with 1D model of oxidation process in cartesian geometry reveals significant differences in time evolution of the oxidation front. Understanding these differences is important for achieving a good control of the oxidation process in cylindrical structures.
Selectivity Modification of SnO2-Based Materials for Gas Sensor Arrays

An enhancement of selectivity of sensor materials, based on nanocrystalline SnO2 is reported. Selectivity toward target gases such as CO, NO2, NH3, H2S and acetone vapor, could be achieved by selection of catalytic cluster distributed over the surface of thick film material. Presented results allow us to propose application of obtained materials in “electronic nose” sensor systems.
Structure-factor probabilities for related structures

Probability relationships between structure factors from related structures have allowed previously only for either differences in atomic scattering factors (isomorphous replacement case) or differences in atomic positions (coordinate error case). In the coordinate error case, only errors drawn from a single probability distribution have been considered, in spite of the fact that errors vary widely through models of macromolecular structures. It is shown that the probability relationships can be extended to cover more general cases. Either the atomic parameters or the reciprocal-space vectors may be chosen as the random variables to derive probability relationships. However, the relationships turn out to be very similar for either choice. The most intuitive is the expected electron-density formalism, which arises from considering the atomic parameters as random variables. In this case, the centroid of the structure-factor distribution is the Fourier transform of the expected electron-density function, which is obtained by smearing each atom over its possible positions. The centroid estimate has a phase different from, and more accurate than, that obtained from the unweighted atoms. The assumption that there is a sufficient number of independent errors allows the application of the central limit theorem. This gives a one- (centric case) or two-dimensional (non-centric) Gaussian distribution about the centroid estimate. The general probability expression reduces to those derived previously when the appropriate simplifying assumptions are made. The revised theory has implications for calculating more accurate phases and maps, optimizing molecular replacement models, refining structures, estimating coordinate errors and interpreting refined B factors.
ELECTRONIC NOSE EVALUATION OF GRAPE MATURITY

Grape maturity is a critical attribute impacting potential wine quality. Maturity evaluation is difficult due to the many interrelated factors that impact physicochemical changes and limitations in the understanding of these factors. Current methods of assessing grape maturity are destructive, expensive, time consuming, subjective, and do not always strongly correlated to potential wine quality. This study evaluated the applicability of a conducting polymer-based electronic nose to monitor grape maturity by analyzing headspace volatiles. In the first part of the study, system and experimental parameters affecting the electronic nose operation were investigated to optimize detection of wine grape aroma. In the second part, the ability of an electronic nose to classify Cabernet Sauvignon (Vitis vinifera L.) grapes based on maturity was investigated. Maturity of samples collected at different weeks post-bloom was evaluated by measuring berry weight, pH, Brix, titratable acidity, total phenols, color intensity, hue, total anthocyanins, and total and phenol-free glycosides. Results were compared, using discriminant and canonical discriminant analysis, with analysis of headspace volatiles via the hand-held electronic nose. The electronic nose was able to determine the difference between the sample groups. Field measurements demonstrated the potential for the electronic nose as a rapid, non-destructive tool for evaluating grape maturity.