Miracle-dz/UniFAR-FTUs huggingface dataset:
Nonpoint source (NPS) model simulation of tillage effects on water quality

Abstract Three agricultural non‐point source (NPS) models, GLEAMS, EPIC, and WEPP, were used to simulate the effects of two tillage systems on runoff and losses of sediment, N, and P from a field‐sized watershed in the Tennessee valley region of Alabama. The field was cultivated with three years of conventional tillage (CvT) followed by three years of conservation tillage (CsT) of cotton. GLEAMS and EPIC underpredicted NO3‐N losses in runoff for both tillage systems. EPIC simulated tillage effects on soluble‐P losses better than GLEAMS. However, EPIC poorly predicted annual organic‐N and P losses in sediment, mainly due to overpredicted sediment losses. The GLEAMS prediction of annual organic‐N and P losses in sediment was more acceptable than that of EPIC. WEPP predicted sediment losses close to observed data for both tillage systems. However, EPIC simulation of sediment loss was not as accurate, because its limited definition of watershed profile prevented the model accounting for sediment deposition on.
Conditioning Film-Induced Modification of Substratum Physicochemistry—Analysis by Contact Angles

Abstract Stainless steel, germanium, polypropylene, and perspex were coated with films derived from marine and freshwater samples and from solutions of model compounds (bovine serum albumin, lactoglobulin, myoglobin, and humic acids). Contact angles of water, formamide, and diiodomethane measured on clean and conditioned interfaces were used to calculate physicochemical surface properties by the Lifshitz–van der Waals acid–base approach, including interfacial parameters for the interaction of carbon- and nitrogen-limited cells of the Gram-negative bacterium SW8 with these surfaces. The interaction parameter φ was evaluated as an indicator of the chemical constitution of conditioned interfaces. Surface free energy and its Lifshitz–van der Waals component were modified by 59 and 66% of conditioning films, respectively, but these alterations were relatively small. The acid–base components of surface free energy and the free energy of adhesion of bacteria to substrata were, however, substantially affected by the coatings. Most films did not modify the interaction parameter φ. Those which did increased the φ of polymeric surfaces and decreased it on stainless steel. The solid–water interfacial tension (γSW), which was larger than the solid–bacterium interfacial tension (γSB) on 97% of surfaces, was reduced by 61% of the conditioning films and increased by 14% of the coatings. The γSBof nitrogen-limited cells was smaller than the γSBof carbon-limited organisms on 92% of substrata. Values of γSBof carbon- and nitrogen-limited organisms were negative on 17 and 69% of the surfaces, respectively. More coatings modified the γSBof nitrogen-limited cells (97%) than the γSBof carbon-limited SW8 (72%). The free energy of adhesion was negative on 31% of interfaces but similar for both phenotypes. It was altered by 91% of conditioning films, which generally reduced its value.
A new synthetic route to hollow Co3O4 octahedra for supercapacitor applications

Co3O4 hollow octahedra were successfully synthesized via a facile one-step solvothermal route. Time-resolved electron microscopy and X-ray diffraction analyses revealed that the Co3O4 hollow octahedra were formed through the self-assembly of primary nanocrystals followed by subsequent Ostwald ripening. Subtle control over the reaction conditions led to different morphologies (hexagonal plates and nanocubes) and crystal structures (β-Co(OH)2–Co3O4 composite). The unique hollow nanostructure rendered our Co3O4 potentially useful for charge-storage applications. To prove its usefulness, the pseudocapacitive performance of the Co3O4 hollow octahedra as a supercapacitor electrode was evaluated and exhibited a charge storage capacity of 192 F g−1 with good long-term cyclability.
Computer Simulations to Study the High‐Pressure Deflagration of HMX

The accepted micro‐mechanical picture of the build‐up of detonation in solid explosives from a shock is that imperfections are a source of hot spots. The hot spots ignite and link up in the reaction zone by high‐pressure deflagration. Although the deflagration is subsonic, there are so many ignition sites that the pressure build‐up is rapid enough to strengthen the initial shock. Quantitative advances in this research require a detailed understanding of deflagration at the high pressure, 1 to 50 GPa, which is present in the reaction zone. We performed direct numerical simulations of high‐pressure deflagrations using a simplified global (3‐reaction) chemical kinetics scheme. We used ALE‐3D to calculate coupled chemical reactions, heat transfer, and hydrodynamic flow for finite‐difference zones comprising a mixture of reactants and products at pressure and temperature equilibrium. The speed of isobaric deflagrations depends on the pressure and initial temperature. We show how this dependence changes with ki.
Effect of Molecular Weight on the Structure and Crystallinity of Poly(3-hexylthiophene)

Recently, two different groups have reported independently that the mobility of field-effect transistors made from regioregular poly(3-hexylthiophene) (P3HT) increases strongly with molecular weight. Two different models were presented: one proposing carrier trapping at grain boundaries and the second putting emphasis on the conformation and packing of the polymer chains in the thin layers for different molecular weights. Here, we present the results of detailed investigations of powders and thin films of deuterated P3HT fractions with different molecular weight. For powder samples, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were used to investigate the structure and crystallization behavior of the polymers. The GPC investigations show that all weight fractions possess a rather broad molecular weight distribution. DSC measurements reveal a strong decrease of the crystallization temperature and, most important, a significant decrease of the de.
Identification of New Ozone Disinfection Byproducts in Drinking Water

Using a combination of spectral identification techniquesgas chromatography coupled with low- and high-resolution electron-impact mass spectrometry (GC/EI-MS), low- and high-resolution chemical ionization mass spectrometry (GC/CI-MS), and infrared spectroscopy (GC/IR)we identified many drinking water disinfection byproducts (DBPs) formed by ozone and combinations of ozone with chlorine and chloramine. Many of these DBPs have not been previously reported. In addition to conventional XAD resin extraction, both pentafluorobenzylhydroxylamine (PFBHA) and methylation derivatizations were used to aid in identifying some of the more polar DBPs. Many of the byproducts identified were not present in spectral library databases. The vast majority of the ozone DBPs identified contained oxygen in their structures, with no halogenated DBPs observed except when chlorine or chloramine was applied as a secondary disinfectant. In comparing byproducts formed by secondary treatment of chlorine or chloramine, chloramine appea.
Comparison of the properties of waterborne polyurethane/multiwalled carbon nanotube and acid‐treated multiwalled carbon nanotube composites prepared by in situ polymerization

A series of waterborne polyurethane (WBPU)/multiwalled carbon nanotube (CNT) and WBPU/nitric acid treated multiwalled carbon nanotube (A-CNT) composites were prepared by in situ polymerization in an aqueous medium. The optimum nitric acid treatment time was about 0.5 h. The effects of the CNT and A-CNT contents on the dynamic mechanical thermal properties, mechanical properties, hardness, electrical conductivity, and antistatic properties of the two kinds of composites were compared. The tensile strength and modulus, the glass-transition temperatures of the soft and hard segments (Tgs and Tgh, respectively), and ΔTg (Tgh − Tgs) of WBPU for both composites increased with increasing CNT and A-CNT contents. However, these properties of the WBPU/A-CNT composites were higher than those of the WBPU/CNT composites with the same CNT content. The electrical conductivities of the WBPU/CNT1.5 and WBPU/A-CNT1.5 composites containing 1.5 wt % CNTs (8.0 × 10−4 and 1.1 × 10−3 S/cm) were nearly 8 and 9 orders of magnitude higher than that of WBPU (2.5 × 10−12 S/cm), respectively. The half-life of the electrostatic charge (τ1/2) values of the WBPU/CNT0.1 and WBPU/A-CNT0.1 composites containing 0.1 wt % CNTs were below 10 s, and the composites had good antistatic properties. From these results, A-CNT was found to be a better reinforcer than CNT. These results suggest that WBPU/A-CNT composites prepared by in situ polymerization have high potential as new materials for waterborne coatings with good physical, antistatic, and conductive properties. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3973–3985, 2005
Nitrogen Transformations during Soil–Aquifer Treatment of Wastewater Effluent—Oxygen Effects in Field Studies

Depth-dependent oxygen concentrations and aqueous-phase total ammonia and nitrate/nitrite ion concentrations were measured in the field during the infiltration of wastewater effluent. Measurements illustrated the dependence of nitrogen fate and transport on oxygen availability. Infiltration basins were operated by alternating wet (infiltration) and dry periods. During infiltration periods, ammonia was removed within the top few feet of sediments via adsorption. Biochemical activity rapidly eliminated residual molecular oxygen in the infiltrate, making the soil profile anoxic. During dry periods, oxygen reentered the basin profile and sorbed ammonia was converted to nitrate via nitrification. Oxygen penetrated to a depth of about 0.6 m (2 ft) within the first few days of dry periods. At greater depths, oxygen levels increased more slowly due to a combination of slow transport kinetics and biochemical (nitrogenous) oxygen demand. During normal wet/dry basin cycles consisting of about 4 wet and 4 dry days, the local vadose zone remained anoxic at depths greater than about 1.5 m (5 ft) below land surface. As a consequence, conditions for denitrification were satisfied in the deeper sediments. That is, the nitrate nitrogen produced in near surface sediments moved freely downward with infiltrating water where it encountered an extensive anoxic zone before reaching local monitoring or extraction wells. The relative importance of dissolved organics and sorbed ammonia as electron donors for denitrification reactions remains to be established.
Determination of Germanium and Tin and Inorganic Tin Species by Hydride Generation in Situ Trapping Flame Atomic Absorption Spectrometry

The analytical performances of a coupled hydride generation, integrated atom trap (HG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system were evaluated for determination of Ge and Sn and inorganic tin species in environmental samples. Germanium and tin hydrides were atomized in air-acetylene flame-heated IAT. A new design of HG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangements (a water-cooled single silica tube, double-slotted quartz tube) permitting construction of an “integrated trap” was investigated. For the estimation of Sn(II) and Sn(IV) concentrations in samples, the difference between the analytical sensitivities of the absorbance singnals obtained for tin hydride without and with previous treatment of samples with L-cysteine could be used. The concentration of Sn(IV) was calculated by the difference between total Sn(tot) and Sn(II). An improvement in limit of detection was achieved compared with that obtained using any of the aforementioned atom trapping techniques separately. The concentration limits of detection were 25 and 8 ng mL−1 for Ge and Sn, respectively. For a 2 min in situ preconcentration time, sensitivity enhancement, compared to FAAS, were 10 and 14 folds for Ge and Sn, respectively, using hydride generation atom trapping technique. The sensitivity can be further improved by increasing the collection time. The relative standard deviations (RSDs) are of the order of 5–10% for this hyphenated technique. The designs studied include slotted tube, single silica tube, and integrated atom trap water-cooled atom traps. The accuracy of this method was tested by analyses of BCS-CRM No.346 (Alloy), GBW 07302 (Stream Sediment), PACS-1 (Marine Sediment), NBS SRM 1633a (Coal Fly Ash), and NIST SRM 1643e (Trace Element in Water) certified reference materials. Agreement between analytical results and certified values for the test elements Ge and Sn (in the range of 1.7–91.0 µg g−1) were in agreement with recommended values. The measured Ge and Sn contents in five referenced materials were in satisfactory agreement with the certified values. The hyphenated technique was applied for germanium and tin determination in coal fly ash, soil, sediment, garlic, sewage, and river water.
Selective Adsorption of Platinum from Mixed Solutions Containing Base Metals Using Chemically Modified Activated Carbons

Abstract: Bituminous coal was activated by using steam at 750°C in a furnace. The activated carbon (AC) particles were chemically treated with thiophosphoric and amine type extractants, then characterized and tested for precious metal selectivity in chloride media. The adsorption of anions [PtCl3−4, PdCl2−4] or cations [PtCl+, PdCKH2O)3+, Ni(H2O)+, Cu2+) on the carbon surface was elucidated by means of complexation and physical adsorption models. Owing to electrostatic repulsion in acidic media (> 1 M HC1), the thio- and amine-treated bituminous ACs did not react with copper and nickel cations. The adsorption rate constant for platinum showed a dependence on solution pH and extractant dosage on the surface of the carbon and was of the order 10− 2 min_1. A three-parameter Toth isotherm best described the adsorption data for single component solutions. Furthermore, platinum adsorption was described by pseudo first order kinetics neglecting the intraparticle diffusivity.
Toxic Potential Evaluation of Particulate Matter Emitted from a Constant Speed Compression Ignition Engine: A Comparison between Straight Vegetable Oil and Mineral Diesel

This study was primarily focused on analyzing particulate matter coming out of engine exhaust from diesel and straight vegetable oils (SVO) for the following parameters: (1) Benzene soluble organic fraction (BSOF), (2) Metal traces, and (3) Particulate surface morphology. Hence, the exhaust from a small compression ignition (CI) engine emitted under varying engine load conditions at constant engine speed was extensively analyzed for its chemical constituents and PM morphology. Two fuels, namely mineral diesel and straight vegetable oil, were tested with this engine and the engine emissions were compared in order to assess their relative toxic potential. One of the major findings of this study suggested that by preheating, viscosity of vegetable oil can be lowered to the level of mineral diesel, and vegetable oil gives better particulate emission results than mineral diesel in terms of lower toxic metal emissions as well as less soot formation.
Predictability of the consistency of porridges using different methods to measure flour swelling

The consistency of porridge made from sweet potato, cowpea, soybean, sorghum, and maize flours was measured in a texture analysis method using back extrusion. The consistency measured was correlated to the swelling volume of the flours, and determined by centrifugation, gravity sedimentation, and least gelation concentration. The reference level of maximum acceptable consistency was estimated from measurements on two ready-to-use child porridges. In general, porridge consistency could not be predicted accurately from swelling volume measured using any of the methods. However, gravity sedimentation, which is the simplest, gave the most consistent results. This method could be used in the field to provide a conservative approximate maximum flour concentration for porridge of acceptable consistency.
Apparent salt sorption reactions in an unfertilized acid subsoil

The equivalent retention of Ca 2+ and SO 4 2- from gypsum solutions in acid subsoils has recently been reported. The term salt sorption has been coined to describe this process, yet little is known about the nature of the reactions involved. This study was conducted to determine if other cation-anion combinations would exhibit similar behavior and to examine the extractability of the sorbed ions. An unfertilized acid Cecil (clayey, kaolinitic, thermic Typic Kanhapludult) subsoil was equilibrated using a saturated paste technique, with solutions of six different salts at a loading rate of =14.0 mmol c kg -1 . The salt solutions used were CaSO 4 , MgSO 4 , Na 2 SO 4 , CaCl 2 , MgCl 2 , and a deionized water control. This soil exhibited salt sorption with all six electrolyte solutions. The SO 4 salts were almost completely sorbed with both cation and anion uptake on the order 13.8 mmol c kg -1 . Calcium and magnesium chloride were sorbed at =11.7 mmol c kg -1 , and NaCI was sorbed at 8.2 mmol c kg -1 . The treated soils were air dried and extracted with successive portions of deionized water or 0.5 M NH 4 NO 3 . A relatively large proportion of both cations and anions were removed by repeated extraction with water, suggesting that ionic strength played an important role in the salt sorption process. Nearly all of the sorbed cations and Cl - were recovered by neutral salt extraction, but <100% of the SO 4 2- could be accounted for by neutral salt extraction. Neutral salt extractable Al was significantly reduced by salt treatment. It appeared that salt sorption in this soil may have resulted from several mechanisms including precipitation, specific adsorption, ionic strength induced charging, and ion pair adsorption operating concurrently.
X-ray powder diffraction investigation of new oxynitride precursors: rare earth oxide compounds of fluorite- and sheelite-type structures in the Yb-(Zr,W)-O system

Nanocrystallized oxide precursors of colored (oxy)nitrides related to the system Yb-(Zr-W)-O have been successfully prepared using a chimie douce process—the amorphous citrate route. The process involves first a formation of fine and homogeneous powdered solids obtained by calcination at 600 °C, a temperature much lower than that of the conventional solid-state method. At this stage, the X-ray diffraction patterns exhibit large line broadening effects. Finally, two well-crystallized and pure quaternary oxides have been readily obtained by heating and under annealing conditions at 850 and 900 °C for 12 h. For one of the patterns, all the X-ray diffraction lines can be easily indexed to a cubic phase with the fluorite structure conforming to the Fm3m space group [Yb2Zr1.21W0. 41O6.65◻1.35 called C-phase: a=5.1864(2) Å]. The second phase adopts the sheelite-type structure [Yb2ZrWO8 called T-phase: space group I41/a, a=5.1584(5), and c=10.8246(6) Å]. By taking into account the present compositions determined by EDS measurements, Rietveld structure refinements produce final RB factors of 0.015 and 0.044, and Rwp factors of 0.069 and 0.089, respectively. In order to characterize the microstructure of the materials (crystallite size and lattice distortion) at the nanometer scale, a study based on diffraction line broadening analysis applying the whole pattern refinement method was also undertaken with confidence. The results show smooth angular variations of the values of FWHMs, indicating that the microstructural properties are isotropic for the cubic and tetragonal oxides. More precisely, the results indicate that whatever the profile fitting approach used (“profile matching” procedure and Rietveld method), the reliability factors Rwp are systematically better with a combined size strain than with zero strain considerations. The strain magnitudes observed for the C-phase-850 °C as well as for the T-phase-900 °C should be viewed as realistic strain.
Effect of nitrogen and potassium on the macro‐nutrient content of fifteen bermudagrass cultivars1

Abstract Information concerning the mineral nutrient composition of various turfgrass species and cultivars is limited. The concentration of nutrients in the turfgrass plant provides an indication of the overall nutrient status and quality of the turf stand. Bermudagrass [Cynodon dactylon (L.) Pers. ] is an important turfgrass utilized throughout the Southeastern and Southwestern states and the transition zone of the United States. A study was conducted to determine the effects of different rates of nitrogen (N) and potassium (K) on the macronutrient content of fifteen bermudagrass cultivars. The cultivars utilized were: ‘Ormond’, ‘Texturf 10’, ‘Tiflawn’, ‘Tufcote’, and ‘U‐3'; ‘Everglades’, ‘Midiron’, ‘Midway’, ‘Pee Dee’, ‘Santa Ana’, ‘Tifdwarf’, ‘Tifgreen’, ‘Tifway’, and ‘Tifway II’ [Cynodon dactylon (L.) Pers. x Cynodon transvaalensis Burtt‐Davey]; and ‘Sunturf’ [Cynodon magennisii Hurcombe], Cultivar plots were replicated three times and were divided into four sub‐plots for the application of N and K mo.
Infrared spectra and kinetics of decomposition of primary ozonides in the liquid phase at low temperatures

A low-temperature i.r. cell has been developed for in situ studies of the intermediates of the ozonolysis of alkenes in the liquid phase at temperatures down to –178°C. The i.r. spectra of 1,2,3-trioxolans (primary ozonides) formed from the following alkenes have been observed: hex-1-ene, cis-di-isopropylethylene, trans-diethylethylene, trans-di-isopropylethylene, and trans-di-t-butylethylene. All have characteristic bands in three spectral regions, 690, 970, and 1 100 cm–1 and at higher temperatures decompose with the formation of 1,2,4-trioxolans (final ozonide) and peroxy-compounds. The decay of the i.r. bands at 690 cm–1 has been used to study the kinetics of the decomposition of the primary ozonides over a range of temperatures. The reactions are first order and have the following A and E factors: trans-diethylethylene, 105.3 s–1, 29 ± 6 kJ mol–1; trans-di-isopropylethylene, 108.4 s–1, 40 ± 3 kJ mol–1; trans-di-t-butylethylene, 1011 s–1, 60 ± 13 kJ mol–1. The activation energies for the decomposition of the primary ozonides from cis-di-isopropylethylene and hex-1-ene are estimated to be lower than 14 kJ mol–1. The observed parameters and the effects of substitution indicate incipient π-bonding and charge separation in the C–O bonds of the transition state and also considerable orientation of solvent molecules.
Ferrimagnetism and spin canting of Zn 57 Fe2O4 nanoparticles embedded in ZnO matrix

The structural and magnetic properties of ZnFe2O4 nanoparticles embedded in a nonmagnetic ZnO matrix are presented. X-ray diffractograms and transmission electron microscopy images showed that the resulting samples are composed of crystalline ferrite nanoparticles with average crystallite size D = 23.4 ± 0.9 nm, uniformly dispersed within the ZnO matrix. Magnetization data indicated a superparamagnetic-like behaviour from room temperature down to TM ~ 20 K, where a transition to a frozen state is observed. The M(H) curves displayed nearly zero coercive field down to TM, where a sharp increase in the HC value is observed. The measured saturation magnetization MS values at 200 and 2 K were MS = 0.028(3) and 0.134(7) μB/f.u. ZnFe2O4, respectively, showing the existence of small amounts of non-compensated atomic moments. Mossbauer measurements at low temperatures confirmed the transition to a magnetically ordered state for T < 25 K, where two magnetically split sextets develop. Whereas these two sextets show strong overlap due to the similar hyperfine fields, in-field Mossbauer spectra clearly showed two different Fe3+ sites, demonstrating that the sample is ferrimagnetically ordered. The two spinel sites are found to behave differently under an external field of 12 T: whereas the moments located at A sites show a perfect alignment with the external field, spins at B sites are canted by an angle αB = 49° ± 2°. We discuss the significance of this particle structure for the observed magnetic behaviour.