Miracle-dz/UniFAR-FTUs huggingface dataset:
Impact of Leaky Sewers on Groundwater Quality

Wastewater from defect sewers can affect groundwater quality. An assessment of this environmental impact for a city of 50 000 inhabitants (Rastatt, SW Germany) was done using marker species distributions, condition monitoring of the sewer network, lab-scale analogy experiments, and specifically instrumented in-situ test sites near defect sewers. The studies revealed elevated concentrations of iodated X-ray contrast media (up to 360 ng/L amidotrizoic acid) and boron concentrations in the urban groundwater which are directly related to leaky sewers. Other common pharmaceuticals could not be detected in the groundwater. Observation wells were installed based on the information from a sewer defect database. These wells focusing on specific sewer leakages show significant changes in groundwater quality parameters.
Modelling cations in three acid soils with differing acid input in Germany

Prediction of concentration changes of cations in soil solutions is complex, and chemical models are necessary for the purpose. The objective of this study was to determine whether the reactions considered in a coupled equilibrium model were appropriate to predict cation concentrations when the initial equilibrium was disturbed by adding small amounts of electrolytes. Multi‐ion sorption in three acid soils (two Cambisols and a Podzol) was studied by sequentially adding small amounts of electrolytes to samples of the soils in batch experiments. A chemical equilibrium model that included inorganic complexation and multiple cation exchange was used to interpret the results. For the subsoils, the solubility of jurbanite was also included in the model.
Synthesis, Characterization, and Biological Activity of Some Transition Metal Complexes Derived from Novel Hydrazone Azo Schiff Base Ligand

A series of metal(II) complexes ML where M = VO(II), Co(II), Ni(II), Cu(II), and Zn(II) have been synthesized from azo Schiff base ligand (N′E)-N′-(5-((4-chlorophenyl)diazenyl)-2-hydroxybenzylidene)-2-hydroxybenzohydrazide and characterized on the basis of elemental analyses, electronic, IR, and 1H NMR spectra, magnetic susceptibility and also by aid of scanning electron microscopy (SEM), X-ray powder diffraction, fluorescence spectral studies, and molar conductivity measurements. Conductivity measurements reveal that the complexes are nonelectrolytes. Spectroscopy and other analytical studies reveal distorted square planar geometry for copper, square-pyramidal geometry for oxovanadium, and tetrahedral geometry for other complexes. Redox behavior of the copper(II) complex has been studied with cyclic voltammetry, and the biological activities of the ligand and metal complexes have been studied against several microorganisms by the well diffusion method. All synthesized compounds can serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The second harmonic generation (SHG) efficiency of the ligand was measured and found to be higher than that of urea and KDP. The SEM image of the copper(II) complex implies that the size of the particles is 50 nm.
Effect of methyl substituents on permeability and permselectivity of gases in polyimides prepared from methyl‐substituted phenylenediamines

Permeability and solubility coefficients for H2, CO2, O2, CO, N2, and CH4 in polyimides prepared from 6FDA and methyl-substituted phenylenediamines were measured to investigate effects of the substituents on gas permeability and permselectivity. The methyl substituents restrict internal rotation around the bonds between the phenyl rings and the imide rings. The rigidity and nonplanar structure of the polymer chain, and the bulkiness of methyl groups make chain packing inefficient, resulting in increases in both diffusion and solubility coefficients of the gases. Polyimides from tetramethyl-p-phenylenediamine and trimethyl-m-phenylenediamine display very high permeability coefficients and very low permselectivity due to very high diffusion coefficients and very low diffusivity selectivity, as compared with the other polyimides having a similar fraction of free space. This suggests that these polyimides have high fractions of large-size free spaces.
Comparison of dielectric properties determined from a computational approach and experiment for anisotropic and periodic heterostructures

The physics of heterostructures is among the forefront problems in materials science. Composite materials also are attractive from the point of view of technological applications such as current-limiting thermistors, radar absorbers, and electromagnetic shields, because they exhibit a variety of interesting mechanical, electric and magnetic properties with the advantage of much reduced cost and weight. To quantify the dielectric response of anisotropic and periodic heterostructures, consisting of two-component composites arranged in a regular simple cubic lattice, in the quasistatic approximation we use an exact numerical technique which is based on a boundary integral equations solution of the Laplace equation which is solved by using the field calculation package PHI3D. 'Exact' means that the correct properties are computed for the given microstructure and choice of individual component properties because all internal electric multipole interactions contributing to the polarization of the material medium are taken into account. The main goal of this work was to confront these numerical calculations with experimental data. Measurements of the effective complex permittivity were carried out in samples composed of identical aligned inclusions, in the form of circular cylinders, embedded in a polymer matrix and filled either by de-ionized water or air. We test our numerical data for two specific examples, i.e. the parallel and perpendicular orientation of the electric field vector with respect to the principal axis of the circular cylinders. Of particular importance is that our numerical simulation captures reasonably well the observed trend in the experimental data over a wide range of volume fraction of inclusions. The experimental results roughly indicate a significant decrease in the permittivity in the x-y plane over that of the z axis, for inclusions containing de-ionized water, while no anisotropy effect is found for inclusions With air. However, there are quantitative differences between the experiment and calculations. These differences were tentatively ascribed to limitations in the experimental model, i.e. finite size, and air bubbles due to ill-controlled filling of the cylindrical inclusions.
Highly conductive PEDOT:PSS films prepared through a treatment with zwitterions and their application in polymer photovoltaic cells

This paper reports the significant conductivity enhancement of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films through a treatment with aqueous solutions of zwitterions for the first time. The conductivity enhancement was dependent on the structure of the zwitterions and the experimental conditions during the treatment, such as the concentration of the zwitterions and the temperature. Conductivity enhancement from 0.2 to 92.4 S cm−1 was observed on PEDOT:PSS films after a zwitterion treatment. The chemical and physical characterizations indicate the lowering of the energy barrier for charge hopping across the PEDOT chains, the loss of poly(styrene sulfonate) acid (PSSH) chains from the PEDOT:PSS film, and the conformational change of the PEDOT chains after the zwitterion treatment. These highly conductive PEDOT:PSS films could be used to replace indium tin oxide (ITO) as the transparent anode of polymer photovoltaic cells (PVs). Power conversion efficiency as high as 2.48% was observed on the polymer PVs with a zwitterion-treated PEDOT:PSS film as the transparent anode.
Prevalência de traumatismo dentário e fatores associados em escolares do município de Palhoça (SC)

O aumento dos niveis de violencia, do numero de acidentes de trânsito e uma maior participacao das criancas em atividades esportivas contribuem para transformar o traumatismo dental em um problema de saude publica emergente. Todavia, ainda ha carencia de dados que mostrem o comportamento deste agravo no Brasil. O objetivo desse estudo foi conhecer a prevalencia de traumatismo na denticao permanente e fatores associados em escolares de doze anos de idade de Palhoca (SC). Foi realizado um estudo transversal envolvendo uma amostra representativa dos escolares (n=405). Os criterios de classificacao do traumatismo foram os mesmos usados no levantamento nacional do Reino Unido. Testou-se associacao entre a prevalencia e fatores clinicos e socioeconomicos por intermedio do qui-quadrado. A prevalencia encontrada foi de 22,5%, sendo estatisticamente maior no sexo masculino. A maioria dos danos traumaticos foram de pequena magnitude, mas encontrou-se alta necessidade de tratamento entre os dentes passiveis de tratamento imediato. Pode-se concluir que foram altas a prevalencia e a necessidade de tratamento do traumatismo dentario em Palhoca. A prevalencia nao mostrou associacao com fatores socioeconomicos ou clinicos.
Application of a glassy carbon electrode modified with functionalized multi-walled carbon nanotubes as a sensor device for simultaneous determination of acetaminophen and tyramine

Multi-walled carbon nanotubes (MWCNTs) were oxidatively functionalized in a mixture of sulfuric acid and nitric acid (3 : 1 v/v) while being ultrasonicated. A simple sensitive electrochemical sensor has been developed for selective determination of tyramine (Tyr) in presence of acetaminophen (Ac) by casting functionalized multi-walled carbon nanotubes (fMWCNT) on the surface of a glassy carbon electrode (GCE). The electrocatalytic oxidation of Ac and Tyr is both individually and simultaneously investigated at the surface of the fMWCNT modified glassy carbon electrode (fMWCNT-MGCE) through using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The electrode is able to completely resolve the voltammetric response of Ac and Tyr from potentially interfering species, e.g. ascorbic acid (AA) and dopamine (DA). By use of DPV, linear calibration curves were obtained for Ac and Tyr over the concentration range up to 100 μM and 85 μM in 0.1 M buffered solutions (pH 7.0), respectively. The proposed sensor has limits of detection of 0.42 μM (3σ) for Ac and 0.8 μM (3σ) for Tyr. Finally, it has been demonstrated that the proposed modified electrode can be successfully used for measuring tyramine and acetaminophen in real samples.
Temporal and Spatial Variation of Phytoplankton Pigments in the Western Part of Ria Formosa Lagoon, Southern Portugal

The spatial and temporal variation of phytoplankton pigments in the western part of Ria Formosa, Portugal, was investigated between September 2000 and July 2002. Sampling stations included the ocean boundary (Ancão inlet) and two different landward boundary situations: 1) the shallow westernmost “blind end” of the lagoon (Ponte) and 2) near a main sewage outlet (Ramalhete). Nutrient concentrations were higher during the first year of sampling but were lower than those recorded in previous studies. This decrease in the concentration of nutrients was possibly the result of the 1997 relocation of the Ancão inlet, which allowed better water circulation in the lagoon. Throughout this study, concentrations of chlorophyll a determined by high-performance liquid chromatography were consistently low. Inter-annual variability in the pattern of chlorophyll a concentration was observed in the form of a bimodal peak (spring/summer and autumn) between September 2000 and June 2001 and more uniform concentrations from September 2001 until July 2002. Principal component analysis of the concentrations of all pigments did not indicate any spatial- or tidal-related variations but did show that pigment concentrations varied over time. Partial least squares analysis corroborated this temporal shift of the phytoplankton pigment abundance and composition and showed that these shifts could be linked to certain environmental variables. Fucoxanthin was the dominant accessory pigment and was strongly correlated with chlorophyll a. Other marker pigments present in lower concentrations included chlorophyll b, 19′-hexanoyloxyfucoxanthin, neoxanthin, alloxanthin, diadinoxanthin, lutein, zeaxanthin, and beta-carotene. PLS analysis was used to infer the dominant phytoplanktonic groups in the lagoon. This analysis established that diatoms and other algal groups with a similar pigment profile dominated the phytoplankton community throughout the year. Cryptophytes were the second most abundant group in the lagoon. The remaining groups, including dinoflagellates, cyanophytes, and chlorophytes, contributed much less to the total algal biomass (generally < 10%).
Chemical characterization of coarse particulate matter in the Desert Southwest – Pinal County Arizona, USA

The Desert Southwest Coarse Particulate Matter Study was undertaken to further our understanding of ambient concentrations and the composition of fine and coarse particles in rural, arid environments. Sampling was conducted in Pinal County, Arizona between February 2009 and February 2010. The goals of this study were to: (1) chemically characterize the coarse and fine fraction of the ambient particulate matter in terms of mass, ions, elements, bulk organic and elemental carbon; (2) examine the temporal and spatial variability of particles within the area using a series of three sampling locations and use this information to determine the contribution of local vs. regional sources; (3) collect, re–suspend, and chemically characterize various crustal sources within the area to identify differences which may isolate them (crustal sources) as independent sources, and; (4) use a receptor based modeling approach to identify particle sources and the relative impact of each on ambient PM concentrations. This work reviews the study objectives, design, site descriptions, and measurement techniques relevant to this research effort and presents the general characteristics of PM during the study period. This unique dataset will support efforts to reduce PM10 and PM2.5 concentrations in the area to below the National Ambient Air Quality Standards (NAAQS) for these pollutants. Coarse particle concentrations are, on average, approximately 5 times fine particle mass concentrations within the region. Coarse particle concentrations in Pinal County are highest during spring and fall seasons, consistent with the tilling and harvesting seasons while fine particles concentrations are highest during fall. Crustal material is the dominant component of coarse particle composition, representing 50% of the mass on average followed closely by organic matter representing 15%. Fine particles still contain a significant crustal fraction (30%) but organic matter dominates at 37% of the particle mass.
Characterisation of the grafting of (3-aminoethyl)aminopropyltrimethoxy silane on precipitated silica

In this study, we have investigated the reaction between (3-aminoethyl)amino-propyltrimethoxysilane (AEPTS) and a precipitated silica in organic solvents. Solid-state 29Si NMR and Karl Fischer titration have been used to produce useful information on the grafted silica samples. AEPTS was chosen in order to characterise the distribution of alkoxysilanes at the silica surface. Indeed, this alkoxysilane has an ethylene diamine function that can form coloured and paramagnetic complexes with copper in 1 ∶ 1 and 2 ∶ 1 molar ratios ([Cu(AEP-Si)]2+ and [Cu(AEP-Si)2]2+). These species have been further identified and quantified by UV-visible and ESR spectroscopies, and the proximity of the alkoxysilanes at the surface was thus traced back through the detection of the 2 ∶ 1 complex [Cu(AEP-Si)2]2+.
HYDROGEN AND HELIUM IONS

ABSTRACT //J24 The present state of knowledge concerning the two lightest atmospheric ions (H' and He') is discussed from the viewpoint of theory and observation. Chemical processes leading to the forma- tion and destruction of these ions, i.e., photoionization and charge transfer, as well as the diffusion process are the controlling fac- tors for the distributions of H+ and He+. The experimental obser- vations of H+ and He' have been obtained by means of ion mass spectrometers aboard spacecraft, ground-based incoherent back- scatter radar, as well as from VLF phenomena observed on satel- lites. These observations show that He' ions do not become a pre- dominant ion at low solar activity, whereas at solar maximum they may play a significant role. Hydrogen ions assume their greatest importance at solar minimum when they are the predominant ion at altitudes even less than 1000 km. There is also a latitude gradient in the relative abundance of these light ions, He' and H+
Magnetic field effects in chemical systems

Abstract Chemical reactions that involve radical intermediates can be influenced by magnetic fields, which act to alter their rate, yield, or product distribution. These effects have been studied extensively in liquids, solids, and constrained media such as micelles. They may be interpreted using the radical pair mechanism (RPM). Such effects are central to the field of spin chemistry of which there have been several detailed and extensive reviews. This review instead presents an introductory account of the field of spin chemistry, suitable for use by graduate students or researchers who are new to the area. It proceeds by giving a brief historical overview of the development of spin chemistry, before introducing the essential theory. This is then illustrated by application to a series of recent developments in solution-phase magnetic field effects (MFEs). The closing pages of this review describe the role played by spin chemistry in the remarkable magnetic compass sense of birds and other animals.
Propriedades físicas e taxa de estratificação de carbono orgânico num Latossolo Vermelho após dez anos sob dois sistemas de manejo

In the clay and heavy clay soils, compaction of the surface layer represents one of the limitations under no-tillage. Under such conditions, periodic soil tillage has been adopted. Other techniques, such as crop rotation are indicated for the physical management of the soil due to a larger input of organic matter and bioporosity of the soil. The objective of this study was to quantify some soil physical properties in an eutroferric Red Latosol (rhodic Eutrudox), the organic carbon content and the soil organic stratification rate after ten years of two soil management systems. The soil management systems included: crop rotation under no-tillage (NT), and crop-sucession under no-tillage, but with soil chiseling before the summer crop (CNT). Larger values of bulk density were verified in NT and macroporosity and total porosity in CNT. In both management systems, the air-filled porosity was above 10 %, suggesting that the aeration conditions were appropriate for the plant roots. The soil water retention curve indicated that the soil under CNT retains more water than under NT at high potentials, but they are similar at potentials below -0.008 MPa. The soil penetration resistance (RP) was larger in NT down to the depth of 0.20 m, independently of the soil moisture content. Results suggested that with identical soil dryness the RP can reach restrictive values for plant growth in NT. Thus, management practices to maintain the soil moisture are necessary to keep the RP lower than the levels considered restrictive for plants. The soil organic content (SOC) was higher in NT down to a depth of 0.10 m, while higher values were observed at depths of 0.10-0.40 m in CNT. The SOC stratification rate in the soil was 1.73 in NT while in CNT it was 1.24. Results show that this highest SOC concentration in NT may result in more stable soil physical conditions for crops.
Trace level detection and identification of nitro‐based explosives by surface‐enhanced Raman spectroscopy

Methods for rapid identification of explosives and their associated compounds at trace level quantities are needed for security screening applications. In this paper, we apply the surface-enhanced Raman spectroscopy (SERS) to detect and identify traces (as low as tens of pg) of pentaerythritol tetranitrate (PETN), ethylene glycol dinitrate (EGDN), cyclotrimethylene-trinitramine (RDX) and trinitrotoluene (TNT) using commercially available substrates (Klarite®, Renishaw diagnostics). High quality spectra were achieved within 10 s with a compact Raman spectrometer. Principal component analysis (PCA) of the data was performed to understand what factors affected the spectral variation across the samples. It was found that 76% of the spectral variation was explained by the first three PCs. Score plots for these components showed that the energetic materials can be clearly classified on the basis of SERS spectra also at trace level quantity. Our measurements further demonstrate the potential for using SERS as fast, in situ analytical tool for safety devices, with a sensitivity which competes and, in some cases, overcomes other techniques. Copyright © 2013 John Wiley & Sons, Ltd.
Characterization of Modified Monosodium Titanate – An Improved Sorbent for Strontium and Actinide Separations

High-level nuclear waste produced from fuel reprocessing operations at the Savannah River Site requires pretreatment to remove 134,137Cs, 90Sr, and alpha-emitting radionuclides (i.e., actinides) prior to disposal onsite as low level waste. An inorganic sorbent, monosodium titanate, is currently used to remove 90Sr and alpha-emitting radionuclides, while a caustic-side solvent extraction process is used for removing 134,137Cs. A new peroxotitanate material has recently been developed and has shown increased removal kinetics and capacity for 90Sr and alpha-emitting radionuclides compared to the current baseline material. This article describes recent results focused on further characterization of this material.
Hysteresis-less inverted CH3NH3PbI3 planar perovskite hybrid solar cells with 18.1% power conversion efficiency

Hysteresis-less inverted ITO/PEDOT:PSS/CH3NH3PbI3 (MAPbI3)/PCBM/Au planar hybrid solar cells with 18.1% average power conversion efficiency irrespective of the scan rate were fabricated by depositing dense pinhole-free MAPbI3 perovskite on a PEDOT:PSS/ITO substrate via a single-step spin-coating of solubility controlled MAPbI3 solution. The conductivities of PEDOT:PSS, PCBM, poly(triaryl amine) (PTAA):tert-butylpyrridne (tBP) + Li-bis(trifluoromethanesulfonyl)imide (Li–TFSI), MAPbI3, and TiO2 were 0.014, 0.016, 0.034, 0.015, and 0.00006 mS cm−1, respectively. The average PL lifetimes (τav) of the inverted and normal cell were 1.277 and 1.94 ns, respectively. The diffusion coefficient (Dn) and charge carrier lifetime (τn) for the inverted MAPbI3 planar hybrid solar cells were increased by 1.14-fold and 1.1-fold, respectively, compared with the conventional FTO/TiO2/MAPbI3/PTAA:tBP + Li–TFSI/Au planar hybrid cells. Hence, the inverted MAPbI3 planar hybrid solar cells exhibited better power conversion efficiency and stability than the conventional MAPbI3 cells because (i) the electron extraction from MAPbI3 to the electron conductor was improved because the electron conductivity of PCBM is higher than that of TiO2; (ii) the EQE value was increased by the better charge injection/separation efficiency between MAPbI3 and PCBM, and by the higher charge collection efficiency than the conventional cell; (iii) the fill factor is improved by the increased Dn and τn; and (iv) the air and humidity stability is improved by the absence of corrosive additives in the device architecture and the hydrophobicity of the PCBM top layer. The reduced current density–voltage (J–V) hysteresis with respect to the scan rate and scan direction in the inverted planar hybrid solar cells could be attributed to a more balanced electron flux (Je) and hole flux (Jh), and a reduced number of surface traps.