Miracle-dz/UniFAR-FTUs huggingface dataset:
Toward automated peak resolution in complete GC × GC–TOFMS chromatograms by PARAFAC

We have previously developed automated PARAFAC methods for resolving peaks from small subsections of data, obtained using comprehensive multidimensional gas chromatography with mass spectral detection (GC × GC–TOFMS). Herein, we build upon those previous methods and present a new method for resolving peaks across much larger sections or even entire GC × GC–TOFMS chromatograms using PARAFAC in an automated fashion. In addition, the method presented is demonstrated on three GC × GC–TOFMS data sets: (1) a complete chromatogram of a test mixture of 32 compounds, (2) several compounds spiked into a diesel sample at two known concentrations and (3) a large section of the chromatogram of the headspace of a urine sample collected by solid phase microextraction (SPME), i.e. containing volatile metabolites. The results of these analyses show that the presented method resolves peaks (including overlapping peaks) and provides useful quantitative and identification information as long as some care is taken in the selection of parameters (such as the size of subsections to be analyzed individually by PARAFAC). Analysis time using PARAFAC remains a challenge, but a technique for reducing the amount of time is demonstrated and future possibilities for greatly reducing the analysis time are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
ASTAXANTHIN FROM SHRIMP SHELL WASTE

The aim of the present study was to propose a simple and efficient method for the isolation of high-value pigment, astaxanthin, from a low-value raw material, shrimp waste. Hexane was used as extraction solvent. The concentration obtained was 43.44 µg/g. Mobile phase for TLC was acetone: hexane in the ratio 3:7 (v/v). The sample was collected from the processing plants, Cochin, Kerala, India. The shrimp waste was transported to the laboratory in a sterile container filled with ice. The organism was identified with the styles marketed under the trade name “red ring”. The wastes generated from the shrimp are cephalothorax, abdominal shell and tail portion. Adhering meat from the cephalothorax was removed and the waste was washed under running water and dried under shade. They were packed in polyethylene bags and stored at -20°C until use. A second set of sample was stored wet, after removing the adhering meat, was packed in polythene covers and stored at -20°C.
Preparation of polylactide by ring-opening polymerisation of lactide

This study was about to produce high molecular weight polylactide (PLA) with via ring-opening polymerisation. Ringopening polymerisation PLA in this study as accomplished using tin(II)octoate as the catalyst with addition of small amount of luaryl alcohol as the co-catalyst. The effects of reaction temperature and pressure on synthesised polylactide were investigated. As-synthesised products were characterised by 1 H-NMR, FT-IR and MALDI-TOF mass spectrometry. The results showed that as-synthesised products were very similar to PLA characteristics reported previously by other researchers. The melting temperature of polylactide was in the range of 130-145๐C. Furthermore, as-synthesised polylactide could not be dissolved completely in many solvents there are just some parts of PLA can be dissolved. Therefore, as-synthesised polylactide could expect to be high molecular weight. In addition, soluble part of polylactide in THF was then characterised by GPC. Moreover, insoluble polylactide was filtered and weighed. With increasing temperature and reducing pressure more residues were collected.
Structural and Molecular Orbital Studies of Si-Phenyl Silaanthracenes

The Si-phenyl derivatives of 1-, 2-, 9- silaanthracenes have been subjected to theoretical analysis with density functional theory (B3LYP/6-31G(d)) to obtain their molecular orbital properties. 2-silaanthracene has been found to be thermodynamically the most stable derivative among the trio. Moreover, the effects of the position of the Si substitution and phenyl attachment on the aromaticity of the parent anthracene have been investigated by NICS calculations at ring centers. The structures have been found to be less aromatic with respect to their unsubstituted counterparts.
An Artificial Neural Network Model for Prediction of Drying Rates

Abstract Drying rate data were generated for training of an ANN model using a liquid diffusion model for potato slices of different thicknesses using air at different velocities, humidities and temperatures. Moisture content and temperature dependence of the liquid diffusivity as well as the heat of wetting for bound moisture were included in the diffusion model making it a highly nonlinear system. An ANN model was developed for rapid prediction of the drying rates using the Page equation fitted to the drying rate curves. The ANN model is verified to provide accurate interpolation of the drying rates and times within the ranges of parameters investigated.
Modellierung und Analyse komplexer Alltagsphänomene: Ein Seminarkonzept zum Umgang mit digitalen Werkzeugen im Physikunterricht

Im Zuge der wachsenden Digitalisierung von allen Aspekten der Schule wandeln sich auch die Anforderungen an die Unterrichtsgestaltung. Auch angehende Physiklehrkrafte sollten schon in der ersten Ausbildungsphase auf diese Anforderungen vorbereitet werden. Hierzu mussen sie Kompetenzen insbesondere zum Einsatz spezifischer digitaler Medien fur das Lehren und Lernen von Physik erwerben. Um dies zu ermoglichen, wurde an der Universitat Paderborn das Seminarkonzept MORPH entwickeln und erprobt. Dabei handelt es sich um einen fachdidaktischen Projektkurs, der den Nutzen digitaler Werkzeuge fur das naturwissenschaftliche Arbeiten betont. Als zentrale Lernaktivitaten nutzen die Teilnehmenden digitale Werkzeuge, um physikalische Alltagsphanomene experimentell zu analysieren und zu modellieren. Neben einer Beschreibung didaktischer Hintergrunde des Konzepts und einer konkreten Umsetzung berichtet der Beitrag zudem die Ergebnisse einer Evaluation der ersten beiden Erprobungen. Dabei stellte sich heraus, dass die Studierenden zwar die angestrebten Fahigkeiten zum Umgang mit digitalen Werkzeugen erwerben, sie aber fur eine Nutzung digitaler Medien in ihrer spateren Unterrichtstatigkeiteher weniger motiviert werden konnten.
Aqueous dispersion of pristine single-walled carbon nanotubes prepared by using a vinylimidazole-based polymer dispersant

In most practical applications, actualizing the inherent properties of single-walled carbon nanotubes (SWNTs) depends strongly on the exfoliation and dispersion of SWNT bundles as individuals and/or small-diameter bundles in various liquid media. Aqueous dispersions are of specific interest in many ways, and polymer dispersants prove to be quite competent for such tasks. To develop a new type of polymer dispersant with accessional function, four water-soluble vinylimidazole (VI)-based polymers bearing different pendant groups were designed, synthesized, and then tested for preparation of aqueous dispersions of pristine SWNTs. The dispersing efficiency was studied as functions of molecular structure and solution nature of VI-polymer. Under assistance of VI-polymers, stable aqueous dispersions are available: the maximal dispersibility reaches 148.9 mg l−1, while initial amount of optimal VI-polymer is merely 0.06 mg ml−1 (∼6 × 10−3 wt%), far below ∼1.0 wt% of sodium dodecyl sulfate (SDS), the most commonly used surfactant, for achieving SWNT dispersion. Biocompatibility of VI-polymer–SWNT complexes obtained from pertinent aqueous dispersions was assessed by culturing L929 cells (mouse fibroblasts), and the results showed that the complex materials were non-toxic to the cells under consideration. The ready dispersions thus pave the way for a variety of applications including those with biological relevance, wherein SWNTs have to face the water-based chemical environments. Besides, it may be more important that the findings, i.e. amphiphilicity and free/sparse of polymer-micelles are two critical factors for VI-polymer to determine its dispersing efficiency, can be potentially applicable to other nanotube/dispersant systems and serve as a common model for developing aqueous dispersions of pristine nanotubes.
Geometry Pattern for the Wire Organic Electrochemical Textile Transistor

Polyelectrolytes are promising materials as gate dielectrics in organic electrochemical transistor. On the other side, the fibre form transistor has become one of the most interesting topics in the field of smart textiles. The use of PEDOT:PSS to realize a parallel wire electrochemical textile transistor has been reported. A new geometry pattern makes the transistor easier to insert into textile fabric making the large-scale production possible. The length of transistor can be up to several centimeters. The On/Off ratio reached up to 10 3 . The switch time is near 15 s. An inverter circuit and a NOR-gated circuit have been realized by wire electrochemical transistors (WECTs). An amplifier was fabricated by using one transistor as well in order to demonstrate the feasibility of fully textile electronic circuits.
Validation and Stability Indicating RP-HPLC Method for the Determination of Sildenafil Citrate in Pharmaceutical Formulations and Human Plasma

A simple, selective, accurate reverse phase-high performance liquid chromatographic (RP-HPLC) method was developed and validated for the analysis of sildenafil citrate in pharmaceutical formulations. Chromatographic separation achieved isocratically on a C18 column (Use Inertsil C18, 5μ , 150 mm x 4.6 mm) utilizing a mobile phase of acetonitrile/phosphate buffer (70:30, v/v, pH 7.0) at a flow rate of 0.8 mL/m with UV detection at 228 nm. The retention time was 4.087. The method is accurate (99.15-101.85%), precise (intra-day variation 0.13-1.56% and inter-day variation 0.30-1.60%) and linear within range 0.1-30 μg/mL (R2=0.999) concentration and was successfully used in monitoring left over drug. The detection limit of sildenafil citrate at a signal-to-noise ratio of 3 was 1.80 ng/mL in human plasma while quantification limit in human serum was 5.60 ng/mL. The proposed method is applicable to stability studies and routine analysis of sildenafil citrate in pharmaceutical formulations as well as in human plasma samples.
Review of testing methods and standards for oil field corrosion inhibitors

Laboratory methodologies to evaluate corrosion inhibitors for oil field application are reviewed. The importance of establishing the factors that influence the hydrodynamic parameters in the laboratory methodologies is discussed. Currently available standards for evaluating and qualifying oil field corrosion inhibitors are presented. Areas where development of new standards is needed are identified. A methodology is presented to predict the performance of corrosion inhibitors in the field, based on laboratory data. (authors)
The Heck Coupling Reaction Using Aryl Vinyl Ketones: Synthesis of Flavonoids

In our previous communication, an α,β-unsaturated aryl ketone was employed as the substrate olefin, which underwent arylation in the Heck coupling reaction. The use of this reagent has allowed us to design a new strategy for the synthesis of flavonoids. In this paper, we illustrate the versatility of the procedure, which was used for the preparation of several chalcones. According to our synthetic scheme, several aryl iodides, selected in order to obtain chalcones differently substituted in ring B, were treated with α,β-unsaturated ketones. All reported syntheses gave high yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Amination-reduction reaction as simple protocol for potential boronic molecular receptors. Insight in supramolecular structure directed by weak interactions

The synthesis of the potential molecular receptors in the amination-reduction reaction has been investigated within the model system comprising (2-formylphenyl)boronic acid and morpholine. The 3-amine substituted benzoxaborole was identified to be the intermediate of the synthesis and the unsubstituted benzoxaborole as the by-product resulting from reduction of the starting material. The insight into the reactivity of the starting materials as well as the intermediate benzoxaborole enabled significant rise in the yield of 2-(aminomethyl) phenylboronic acids synthesis. The solid state structure of 2-(piperidylmethyl)phenylboronic acid has been re-determined, and the description of the molecule and the crystal is given. The supramolecular layer structure directed by the weak C-H…O and C-H…π interactions was identified and scrutinized based on the geometry and Hirshfeld surface analyses
On the relation between X-ray Photoelectron Spectroscopy and XAFS

XAFS and X-ray Photoelectron Spectroscopy (XPS) are element specific techniques used in a great variety of research fields. The near edge regime of XAFS provides information on the unoccupied electronic states of a system. For the detailed interpretation of the XAFS results, input from XPS is crucial. The combination of the two techniques is also the basis for the so called core-hole clock technique. One of the important aspects of photoelectron spectroscopy is its chemical sensitivity and that one can obtain detailed information about the composition of a sample. We have for a series of carbon based model molecules carefully investigated the relationship between core level photoelectron intensities and stoichiometry. We find strong EXAFS-like modulations of the core ionization cross sections as function of photon energy and that the intensities at high photon energies converge towards values that do not correspond to the stoichiometric ratios. The photoelectron intensities are dependent on the local molecular structure around the ionized atoms. These effects are well described by molecular calculations using multiple scattering theory and by considering the effects due to monopole shake-up and shake-off as well as to intramolecular inelastic scattering processes.
Fire as a Management Tool for a Tropical Woody Weed: Mimosa pigra in Northern Australia

Abstract The use of fire for managing infestations of the invasive tropical shrub Mimosa pigra was investigated in a field experiment and with small-scale fires in containers. In the field experiment, gelled gasoline was applied to thickets of mimosa from a helicopter. When applied in a spiral pattern, the fire became intense and self-propagating, clearing the thicket completely. When applied along a straight line, the fire quickly burnt out and failed to destroy the stand. Seeds exposed to fire in the field, and in containers, died or became germinable. Deaths were most common at the soil surface, while enhanced germination occurred below the surface, down to a depth of 5 cm, but no deeper. Fire may therefore be used, both on small and large scales, to deplete that seed bank of mimosa by killing or germinating a large proportion of the seeds, allowing their simultaneous treatment with herbicides. Because a proportion of seeds may remain at depths greater than 5 cm, however, follow-up control must be practised.
Effect of high pressure on polymorphic phase transition and electronic structure of XAs (X=Al, Ga, In)

The structural and electronic properties of XAs (X = Al, Ga, In) under pressure have been investigated using ab-initio pseudo-potential approach within local density approximation in B3→B1→B2 phases. The values of phase transition pressures show reasonably good agreement with the experimental data and better than others. The B1→B2 phase transition in InAs is not seen. The volume collapse computed from equation of state (EOS) is found to be in good agreement with the experimental values. Under ambient conditions, the energy of B3 phase is lowest as compared to other phases, while at high pressures beyond B1→B2 phase transition, the energy of B2 phase is found to be lower than that of B1 phase showing correct stability of the phases. There is relatively smaller enthalpy associated with B3→B1 transition as compared to B3→B2 transition. The electronic structures have also been computed at different pressures. We have also reported the effect of pressure on energy gap and valence band width.
Characteristics of Facing Target-Sputtered Amorphous InGaZnO Thin Films as the Active Channel Layer in Transparent Thin Film Transistor on Polymeric Substrate

For an application to the channel layer in flexible transparent thin-film transistor (TFT), we have prepared the amorphous indium gallium zinc oxide (a-InGaZnO) thin films on unheated polyethylene naphthalate (PEN) substrate by facing target sputtering. Two types of a-InGaZnO TFT design, one top gate configuration and the other bottom gate, have been fabricated for comparison with each other. The experimental results reveal that the top gate a-InGaZnO TFT is shown to be superior TFT performances, compared with bottom-gate structure. As a result, the top gate a-InGaZnO TFTs operate in depletion mode with a threshold voltage of −0.5 V, a mobility of 6.0 cm2/Vs, an on-off ratio of >106, and a sub-threshold slope of 0.95 V/decade. In addition, the optical transmittance of about 74% at 550nm wavelength is represented for the top gate a-InGaZnO TFT on PEN.
Distribution and source apportionment of atmospheric non–methane hydrocarbons in Mumbai, India

Concentrations of non–methane hydrocarbons (NMHCs) in atmosphere were measured at six urban sites in Mumbai from February 2005 to January 2006. Seventeen hydrocarbons, i.e., ethane, ethylene, acetylene, propane, propylene, iso–butane, n–butane, iso–pentane, n–pentane, hexane, benzene, heptane, toluene, ethyl benzene, p–xylene, o– xylene and n–decane have been identified in 254 urban air samples using a cryogenic pre–concentration system attached to a Gas Chromatograph (GC) with a Flame Ionization Detector (FID). C2–C5 hydrocarbons were determined on 2 m x 2 mm i.d. , stainless steel (S.S.) column packed with n–octane/Poracil C. The components of C6 and above are determined on a 3 m x 2 mm i.d. , S.S. column filled with 10% OV – 101 on chromosorb WAW. All these species show well–defined winter season (November–February) high and summer season (March–June) low values. Factor analysis (FA), a receptor modeling technique, has been used for quantitative source apportionment. Varimax rotated factor analysis identified five possible sources. The mean percent contribution from the vehicular exhausts was found to be 33% while that from refinery sources contribute 21%. Petrochemical industries and paint solvent contributed 15% and 11% respectively. Eight percent of the NMHCs were coming from polymer manufacturing industries. The remaining 12% is contributed by other unidentified sources.
Droplet dynamics in internally mixed twin-fluid spray

Effervescent atomizers are based on the mixing of gas with liquid prior to discharge. We describe the discharge of a two-phase mixture and movement of droplets in a gas jet using simple theoretical models, following with elucidation of droplets dynamics using experimental data for an effervescent spray. Discharge of the liquid-gas mixture from the nozzle is solved using a combination of two discharge models. Depending on operation conditions, 59– 64% of the total discharged mass corresponds to the Separated Flow Model and the rest to the Homogeneous Flow Model. Discharge velocity of the liquid is 12– 27% of the gas exit velocity. The liquid-gas velocity ratio is negatively correlated with gas-to-liquid mass ratio (GLR) and positively correlated with inlet pressure. Radial profiles of axial droplet velocity, as measured using Phase Doppler anemometry, are axisymmetric bell-shaped with a maximum in the centreline analogous to the profile defined for a simple gas jet which, however, is more flat near the centreline and declines much faster for higher radial positions. Mean velocity in individual spray positions varies with particle size within a range of several m/s typically. This variation is closely related to particle Stokes number, Stk. Variation of mean velocity with operation pressure and GLR can be explained with discharge conditions; higher pressures and GLRs lead to higher discharge velocities that are reflected in the spray downstream. Stokes numbers are generally 10 and very weakly interact with the gas.
Analysis of Polymer Dynamics by NMR Modulated Gradient Spin Echo

NMR modulated gradient spin echo method, which allows the quantification of polymer segmental displacement via the measurement of the velocity autocorrelation, requires the formulation of theoretical predictions in the frequency domain in order to test their validity. We worked out the velocity autocorrelation spectrum of the segmental motion according to the Rouse and the tube/reptation model to compare it to the experimental results obtained by the new NMR technique. The analysis of polybutadiene shows the segmental velocity autocorrelation spectrum typical for the reptation-like motion of polymer in a “tube”. The measurement of bulk water indicates a kind of Rouse motion in a network of hydrogen bonds.
Cover Crop Effects Increasing Carbon Storage in a Subtropical No‐Till Sandy Acrisol

The long‐term (8‐year) effects of summer (Mucuna spp.) and winter cover crops (Avena strigosa + Vicia sativa and Lolium multiflorum + Vicia sativa) in maize‐based cropping systems on the total, particulate, and mineral‐associated soil carbon (C) stocks in the 0‐ to 0.2‐m layer of a no‐till South Brazilian Acrisol (87 g kg−1 clay) were evaluated. Annual C sequestration rates and the carbon management index (CMI) were calculated taking a fallow/maize (F/M) system as reference. A greater average C sequestration rate (0.68 Mg ha−1 yr−1) and greater C lability (particulate C/mineral‐associated C) were observed in the soil under the Mucuna system, and this was related to the higher biomass input in comparison to the winter cover crop systems. These cropping system effects on amount and lability of soil C were summarized through the CMI. The results highlight the potential of C retention in soils under warm and humid subtropical climate through the adoption of high C input summer cover crops in no‐till production systems aimed at further improvement in soil and environmental quality.
Prediction of Droplet Diameter for Microchannel Emulsification

Recently, we proposed microchannel (MC) emulsification, a novel method for making monodisperse emulsions using a microfabricated channel array. The previous study demonstrated that droplet size is affected by MC geometry. This study proposes a model for the prediction of droplet diameter based on the droplet formation mechanism and on experimental observation. The MC structure used in this study is composed of a narrow channel and a terrace. The terrace is a microfabricated slitlike shape, on which the dispersed phase inflates to a disklike shape. The MC geometry is defined in terms of two variables, terrace length (L) and MC depth (H). First, the relationship between droplet diameter and MC geometry was investigated experimentally. Experimental observation suggests that the dispersed phase, which is within the detachment length (A) from the terrace end, detaches and forms a droplet. The droplet volume was estimated from the volume of the dispersed phase that detaches from the terrace during this process.