Miracle-dz/UniFAR-FTUs huggingface dataset:
Drinking Water Denitrification Using A Novel Ion-exchange Membrane Bioreactor

A novel ion-exchange membrane bioreactor, able to prevent secondary pollution of biologically treated drinking water, was developed and specifically tested for water denitrification. This system combines ion-selective membrane dialysis and biological conversion. The ion-selective membrane facilitates the extraction of the pollutant from the water to the biological compartment, hinders the transfer of organic and inorganic nutrients, and confines the microbial culture involved in the conversion process within the bioreactor. In the study hereby presented the system was used to investigate the removal of nitrate from a synthetic groundwater containing 50 mg−N L-1 of nitrate. The treated water obtained was free of inorganic nutrients and ethanol, the carbon source was selected for the biological process, and the surface denitrification rate achieved was 7 g−N m-2 day-1. This system proved to be effective in producing a treated water effluent that does not require the extensive posttreatment associated with c.
Simple enzyme immobilization inside glass tubes for enzymatic cascade reactions

The two enzymes Aspergillus nigerglucose oxidase (GOD) and horseradish peroxidase (HRP) were immobilized with a simple and quick procedure inside micropipette glass tubes with the help of the avidin–biotin system and of a biotinylated second generation polycationic dendronized polymer (de-PG2). De-PG2 strongly adheres to SiO2 surfaces and served as soft organic layer for non-covalently gluing the biotinylated enzyme–avidin complexes to the solid glass surface. The immobilized enzymes remained highly active for a period of several weeks. Furthermore, after connecting a glass tube containing immobilized GOD (first tube) with a glass tube containing immobilized HRP (second tube), this system was applied as a simple flow reactor for the spectrophotometric quantification of D-glucose in aqueous solution via a cascade reaction catalysed by the two immobilized enzymes. Moreover, preliminary measurements showed that the general procedure developed for the immobilization of HRP and GOD inside the glass tubes can also be applied to E. coli β-galactosidase, allowing the spectrophotometric determination of lactosevia a three-enzyme cascade reaction in a system composed of three sequentially connected tubes. The success of the work is based on two factors: (i) on the use of the dendronized polymerde-PG2 which combines properties of polycationic dendrimers as well as polycationic polymers in one and the same molecule, leading to efficient and reproducible binding to SiO2 surfaces; and (ii) on the monitoring of the immobilization on SiO2 with the transmission interferometric adsorption sensor (TInAS) for elaborating the optimal experimental conditions for the immobilization of the enzymes inside the tubes.
Electronic structure study of lightly Nb-doped TiO2 electrode for dye-sensitized solar cells

To improve the conversion efficiency of dye-sensitized solar cells (DSSCs) it is necessary to understand the electronic structure of the TiO2–dye–electrolyte interface in detail. A sturdy junction at the interface can be provided by modifying the electronic structure of the TiO2 electrode with Nb doping. The Nb-doped TiO2 was prepared by a sol–gel method followed by a hydrothermal treatment; the Nb content was varied from 0.5 to 3.0 mol%. The X-ray photoelectron spectroscopy showed that the Fermi level of TiO2 electrode shifted away from the conduction band minimum (CBM) when the Nb content is low (≤1.5 mol%) and shifted toward the CBM when the Nb content is high (≥2.5 mol%). The shift of Fermi level with low Nb doping was due to the passivation of the oxygen vacancies at the TiO2 nanoparticle surface. Intraband states were formed when dopant content was 1.5 and 2.5 mol%. We have found that the photovoltaic parameters of DSSCs based on doped TiO2 sensitized with a cis-[Ru(dcbpyH)2(NCS)2](NBu4)2, N719 dye, are closely related to the electronic structure of the Nb-doped TiO2 electrode. The changes of short circuit current and open circuit voltage of DSSCs were explained in relation to the electronic structure of the TiO2 electrode. The best efficiency of 8.0% was demonstrated by DSSCs with 2.5 mol% Nb-doped TiO2.
Fabrication of functional polypyrrole (PolyPyr)-nanotubes using anodized aluminium oxide (AAO) template membranes. Compromising between effectiveness and mildness of template dissolution conditions for a safe release of PolyPyr-nanotubes

Functional acidic (COOH) pyrrole (Pyr)-containing oxidizable monomers can be template-polymerized using hard nanoporous anodized aluminium oxide (AAO) membranes in liquid phase polymerization (LPP) conditions. Accordingly, the safe and effective release of resulting functional polyCOOH–polypyrrole (polyPyr)-nanotubes from template membranes must be operated in controlled acidic, instead of commonly used Martin-like basic conditions (membrane digestion).
Facile synthesis of porous bismuth–carbon nanocomposites for the sensitive detection of heavy metals

This article describes the facile and scalable synthesis of carbon xerogel–bismuth nanoparticle composites using two different approaches. It also demonstrates the high potential of these materials for developing electrochemical sensors, which could simultaneously analyze in a rapid test very low concentrations (<1 ppb) of heavy metals in water. The microstructural characterization of the composites by different techniques revealed a microporous carbon structure with evenly dispersed spherical Bi nanoparticles whose dimensions depend on the synthesis conditions. Sensors prepared with the nanocomposites were used to test the electrochemical performance of the materials for the detection of several heavy metal ions in water such as cadmium and lead, which are included in the list of priority substances of most water policies. The minimum concentration detected for these two species was 0.6 ppb for an overall analysis time of below 5 min. This concentration is well below the maximum limits allowed in drinking water according to the most stringent regulations, and of the order of the maximum allowance concentration of environmental quality standards.
Flow behavior of an Eyring fluid in a nanotube: The effect of the slip boundary condition

The flow of an Eyring fluid in a nanotube is analyzed by using continuum mechanics. The results reveal that the Eyring fluid flows like a Newtonian fluid at small pressure gradient and a pluglike fluid at high pressure gradient. The flow rate of the Eyring fluid in the nanotube at high pressure gradient with the Navier slip condition is several orders of magnitude higher than the Hagen-Poiseuille result for the flow of Newtonian fluids in the nanotube. This trend is similar to the experimental results reported in literature, suggesting that the Eyring fluid can be used to model nanoscale fluid flow.
Polyketide-peroxides from a Species of Jamaican Plakortis (Porifera: Demospongiae)

A new cyclic peroxide plakortisinic acid (1), and a new ketone derivative (2), in addition to six known compounds, an α,β-unsaturated ester (3), plakortide N (4), plakortide F (5) and its free acid (6), plakortone D (7), and a furan-containing molecule (8), were isolated from a species of Plakortis from Jamaica. The structures were elucidated by interpretation of 1D and 2D NMR spectra, and mass spectrometry data and by comparison with data from the literature. Comparison between experimental and calculated optical rotations allowed the assignment of absolute configuration of 1 and 2. The isolated compounds have been evaluated for their antimicrobial, antimalarial, anticancer, anti-Mtb, and anti HIV-1 activity.
Wall slip in polymer melts

We present a review of the recent characterizations of the flow behaviour of high-molecular-weight polymer melts, with special emphasis on situations in which slip at the wall appears. These characterizations are based on direct measurements of the local velocity of the fluid, in the immediate vicinity of the solid wall, through near-field velocimetry techniques. The results demonstrate the importance of polymer molecules anchored on the solid surface, either by strong adsorption or by chemical grafting, and entangled with the bulk polymer, to produce a strong friction at low shear rates and to lead to a shear rate threshold above which strong slip at the wall and low friction develop. The evolution of the shear rate threshold and of the flow characteristics (the length of the extrapolation of the velocity profile to zero, the critical slip velocity for the onset of strong slip, .) with the molecular parameters of the system (the molecular weights of the bulk and surface chains, and the surface density of anchored chains) is analysed and compared with the predictions of recent theoretical models.
Atomic Absorption Spectrophotometric Determination of Cadmium

In the determination of cadmium by atomic absorption spectrophotometry(AAS), the interfering effects of different species can be completely eliminated by adding excess cyanide. The mechanism by which the cyanide eliminates interference by influencing the atomization process is discussed. Also the AAS for the analysis of cadmium in complex form is elaborated. The aim of this investigation is to achieve a determinate characterization of compound formation. The way to reach this purpose is the utilization of the continuous titration technique.
Quantification of homonuclear dipolar coupling networks from magic-angle spinning 1H NMR

Numerical simulations of magic-angle spinning (MAS) spectra of dipolar-coupled nuclear spins have been used to assess different approaches to the quantification of dipolar couplings from 1H solid-state NMR. Exploiting the translational symmetry of periodic spin systems allows extended networks with ‘realistic’ numbers of spins to be considered. The experimentally accessible parameter is shown to be the root-sum-square of the dipolar couplings to a given spin. The effectiveness of either fitting the resulting spinning sideband spectra to small spin system models, or using analyses based on moment expansions, has been examined. Fitting of the spinning sideband pattern is found to be considerably more robust with respect to experimental noise than frequency domain moment analysis. The influence of the MAS rate and system geometry on robustness of the quantification is analysed and discussed.
Synthesis of novel functionalised symmetric bi-2(1H)-pyrazinones

A simple and convenient synthesis for functionalised bi-2(1H)-pyrazinones 9, lla-h starting from 3,5-dichloro-2(1H)-pyrazinones 7, 10a-h is described. The pyrazinone is homo-coupled by means of a Suzuki-type reaction of an in situ generated boronate. The reactions were carried out under conventional heating as well as under microwave irradiation and dramatic improvements in the rates and yields have been observed under the latter conditions.
Cooling rate dependence of the glass transition temperature of polymer melts: Molecular dynamics study

A coarse-grained bead spring model of short polymer chains is studied by constant pressure molecular dynamics (MD) simulations. Due to two competing length scales for the length of effective bonds and the energetically preferred distance between nonbonded beads, one observes a glass transition when dense melts are cooled down (as shown in previous work, at a pressure p=1 the mode coupling critical temperature is at Tc≈0.45 and the Vogel–Fulcher temperature is T0≈0.33, in Lennard-Jones units). The present work extends these studies, estimating a cooling-rate-dependent glass transition temperature Tg(Γ) by cooling the model system from T=0.6 down to T=0.3, applying cooling rates from Γ≈10−3 to Γ≈10−6 (in MD time units), and attempting to identify Tg(Γ) from a kink in the volume versus temperature or potential energy versus temperature curves. It is found that Tg(Γ) lies in the range 0.43⩽Tg(Γ)⩽0.47, for the cooling rates quoted, and the variation of Tg(Γ) for Γ is compatible with the expected logarithmic va.
Boron nitride nanotube branched nanojunctions

One-dimensional boron nitride (BN) nanotube nanojunctions are of great interest for both fundamental and applied research because of their stable and excellent mechanical and physical properties. Large quantities of highly pure BN nanotube multiple Y- and/or T-junctions were synthesized by annealing pure boron nanowire precursors in N2 atmosphere at 1500 °C. Transmission electron microscopy and electron energy-loss spectroscopy studies reveal that the products possess a concentric tubular structure and stoichiometric BN composition. The boron nanostructured precursors react with nitrogen at high temperature to form the corresponding BN components, retaining their original morphologies. A non-equilibrium interdiffusion of nitrogen and boron might be involved in the transformation process of the solid boron nanowires to hollow BN nanostructures. Our results illustrate the technological potential of BN nanoscale multiple junctions being incorporated into future nanoscale mechanical and electronic devices.
Synthesis of silver powder using a mechanochemical process

Fine silver powder was synthesized in a mechanochemical process by inducing a solid-state displacement reaction between AgCl and sodium. The process employed was ball milling in a planetary-type ball mill. The reaction products were elemental silver and NaCl in powder form. The silver particles were separated out by washing the NaCI by-product from the milled powder mixture. The milled powders were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD determination showed that the reaction between AgCl and sodium was complete in almost all the experiments carried out. In some cases a minor quantity of Ag 2 Na was formed. SEM and TEM examinations revealed that, depending on the milling parameters employed, the size of the particles in the synthesized metallic silver powder was in the range 50-1000 nm.
Theoretical and Experimental Investigations of the Nonlinear-Optical Properties of Vanillin, Polyenovanillin, and Bisvanillin Derivatives

The potential interest of vanillin, isovanillin, thiovanillin, and isothiovanillin as starting units for the design of hyperpolarizable molecules such as polyenovanillin (Ar-(CH=CH) n -CH=O) and bisvanillin derivatives was investigated by a CNDO/S method using a specific program that allowed the calculation of all the components of the first-ordcr molecular hyperpolarizability tensor β in nonpolar solvents. The reliability of the calculations was assesscd by comparison with EFISH measurements on model systems. Among the vanillin derivatives, thiovanillin, where the sulfur group is in para to the aldehyde group, showed the largest hyperpolarizability, β
A General Energy Balance for Battery Systems

A general energy balance for battery systems has been developed. This equation is useful for estimating cell thermal characteristics. Reliable predictions of cell temperature and heat generation rate are required for the design and thermal management of battery systems. The temperature of a cell changes as a result of electrochemical reactions, phase changes, mixing effects, and joule heating. The equation developed incorporates these effects in a complete and general manner. Simplifications and special cases are discussed. The results of applying the energy balance to a mathematical model of the LiAl/FeS cell discharged through two different reaction mechanisms are given as examples. The examples illustrate how the energy equation may be applied to a specific system to examine the relative contributions corresponding to the terms in the equation. The examples show that the processes involved in cell heat generation may be complex and that the application of a sufficiently general energy equation is advantageous.
Quantification of the soot-water distribution coefficient of PAHs provides mechanistic basis for enhanced sorption observations

There is an increasing recognition of the necessity to consider the heterogeneity of geosorbents, and in particular the condensed carbon facies fraction, to improve prediction of hydrophobic pollutant phase speciation. Field observations of much elevated organic-carbon normalized distribution coefficients (Koc) of PAHsrelative to predictions from bulk organic-matter partitioning modelshave been suggested to be explainable by soot sorption. To afford testing of this hypothesis, we here report on the soot-water distribution coefficients (Ksc) for a series of PAHs (naphthalene (NP), fluorene (FL), phenanthrene (PH), and pyrene (PY)) using diesel particulate matter (NIST standard reference material SRM-1650) as model soot sorbent. Specifically adapted batch and column experiments yielded average log Ksc values of 5.23, 5.40, 5.82, and 6.59 (batch) and 4.63, 6.03, 6.62, and 7.03 (column) for NP, FL, PH, and PY, respectively (all data in [Lw/kgsc]). The obtained values are 35−250 times higher than respective Ko.
Synthesis and properties of polyimide-clay hybrid films

Polyimide-clay hybrid films with four different sizes of clay minerals have been synthesized to investigate the effect of the size of clay minerals to the properties of the hybrids. Hectrite, saponite, montmorillonite, and synthetic mica were used as clay minerals. Those clays consist of stacked silicate sheets about 460 A (hectrite), 1650 A (saponite), 2180 A (montmorillonite), and 12300 A (synthetic mica) in length, 10 A in thickness. The longer the length of clay mineral was, the more effectively properties of polyimide were improved. In the case of polyimide-mica hybrid, only 2 wt % addition of synthetic mica brought permeability coefficients of water vapor to value less than one-tenth of that of ordinary unfilled polyimide, and thermal expansion coefficient was lowered at the level of 60% of the original one. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2289–2294, 1997
Modeling Dormant Bud Cold Hardiness and Budbreak in Twenty-Three Vitis Genotypes Reveals Variation by Region of Origin

Cold injury is a key environmental challenge in many grape-producing regions, especially those at high latitudes. Although grapevines acclimate to cold temperatures in fall and deacclimate when warm temperatures return in spring, cold hardiness varies with species, cultivar, phenology, ambient weather, photoperiod, and plant organ, which hampers implementation of effective mitigation practices. Using long-term data sets of lethal temperatures and spring phenology for primary buds of Vitis vinifera and Vitis labruscana, we parameterized and evaluated a discrete-dynamic model that simulates cold hardiness from early fall through budbreak of 23 genotypes. The model uses mean daily temperature as the sole input variable to drive daily changes in hardiness. Genotype-specific parameters, such as initial and maximum hardiness, temperature thresholds, acclimation and deacclimation rates, and chilling and heating requirements, were optimized through an iterative process. The model predicted cold hardiness with 0.89 ≤ r2 ≤ 0.99, depending on genotype. Because it simulates hardiness at budbreak, the model can also be used to predict the time of budbreak. Optimized model parameters revealed a north/inland-south/coastal gradient for genotype origin in terms of initial and maximum cold hardiness, and time of budbreak. Budbreak occurred earlier in hardier genotypes, consistent with more rapid deacclimation of genotypes originating from colder climates, paradoxically making these genotypes more vulnerable to spring frost in warmer environments. The current model of grapevine bud cold hardiness has uses in both climate modeling and risk assessment.
Engaging the disengaged: A shop teacher’s reflection on project authenticity

This autoethnographic study examines an experiment with project authenticity completed with high school students seven times over an eight-year period. These projects involved the building of full-sized homes by grades 10 through 12 students, within a standard carpentry curriculum on the site of a conventional high school within the province of Prince Edward Island. Prior construction course projects consisted of small storage barns. Prefabricating and placing four-bedroom homes to the national building code represented a significant departure from the status quo and considerable risk on many levels. This cottage course as it became known enhanced student engagement and drew a balanced demographic of students into a carpentry program that had become skewed towards the lower academic levels in terms of class composition; all levels became engaged with the construction process. The experiment came at excessive personal cost to myself and was ultimately terminated. The search for a comparable replacement course led to a series of reflections on the multitude of factors that influence student engagement and program success in a shop class setting.
Anomalous Codeposition of Iron Group Metals: II. Mathematical Model

A mathematical model for anomalous codeposition of iron group metals is presented which describes effects of inhibition and enhancement observed experimentally during codeposition of FeNi, NiCo, and FeCo alloys. The model assumes three parallel reaction paths each one proceeding in two consecutive steps and it takes into account the effect of mass transport. The model assum es that deposition involves an adsorbed reaction intermediate containing both metal ions in partly reduced form. This reaction int ermediate is responsible for both the inhibition of the more noble species and the enhancement of the less noble species. Differe nces in the deposition behavior of the three alloy systems considered are due to differences in the surface coverage of the mixed re action intermediate. The theoretical predictions of the model are compared with experimental data obtained under well-defined mas s transport and current distribution conditions. The model can simulate in a satisfactory way the observed effects of inhibition and enhancement due to codeposition and it predicts correctly the influence of mass transport. It is less successful in the simulat ion of the influence of the concentration of reacting species. Possible reasons for this behavior are discussed and research direction s for improving the model are outlined. © 1999 The Electrochemical Society. S0013-4651(98)10-089-7. All rights reserved.
Photocurrent Spectra and Fast Kinetic Studies of P3HT/PCBM Mixed with a Dye for Photoconversion in the Near-IR Region

Photoconversion properties are demonstrated for a device based on a small dye molecule, absorbing light in the near-IR region, mixed with two organic charge transport materials and together forming a dye-sensitized organic bulk heterojunction. The organic dye molecule, phthalocyanine (1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine), mixed with a blend of poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C-61 (PCBM), shows a photoconversion spectrum extended more than 150 nm toward longer wavelengths, as compared to a device without such dye sensitization. In the dye-sensitized region of the photoconversion spectrum the maximum infernal quantum efficiency was estimated to 40%. With higher dye concentrations the internal quantum efficiency decreases. Transient laser spectroscopy measurements show that after excitation of the dye there is an electron transfer from the dye to PCBM and a subsequent hole transfer from the dye to P3HT, which results in a long-lived (P3HT(+)/dye/PCBM-) charge-separated state.