Miracle-dz/UniFAR-FTUs huggingface dataset:
Pretreatment and desalination of flowback water from the hydraulic fracturing

AbstractA process based on pre-treatment and membrane desalination was studied for the treatment of the flowback water from drilling for shale gas in Lubocino in Poland. The effectiveness of pre-treatment technology, which contained NaOH alkalization, KMnO4 oxidation, filtration, sorption, and fine filtration, was studied. Also the usefulness of nanofiltration (NF) and reverse osmosis (RO) membranes for flowback desalination was tested. The study was carried out in the semi-pilot scale. The applied pre-treatment technology made possible to obtain a product that can be placed on the NF and RO elements (turbidity = 0.882 NTU, silt density index = 3.1). The 4040-SR100-N2 NF element was ineffective for flowback water purification, and the retention of contaminants was low (5.1% conductivity, 18.2% total hardness, 9.2% TOC). The AG4040FM RO element was characterized by higher retention (conductivity 93.9%, total hardness 98.3%, TOC 78.1%), but low volume concentration ratio (VCR) (VCR = 1.6) with more than 50%.
Dissolved organic matter sorption on sub soils and minerals studied by 13C‐NMR and DRIFT spectroscopy

Sorption on the mineral matrix is an important process restricting the movement of dissolved organic matter (DOM) in soils. In this study, we aimed to identify the chemical structures responsible for the retention of DOM by sorption experiments with total DOM and acidic humic substances (AHS), containing humic and fulvic acids, on soil samples and minerals (goethite, ferrihydrite, and amorphous Al(OH)3). The AHS remaining in solution after sorption were studied by 13C nuclear magnetic resonance (NMR) analysis, and total DOM and AHS for bed on the surfaces of minerals by diffuse reflectance Fourier‐transform infrared (DRIFT) spectroscopy. The soil samples were taken from strongly sorbing Bw horizons of two Inceptisols rich in pedogenetic Fe (29 and 35 g kg −1) and containing little C (7 and 22 g kg−1). The 13C‐NMR spectra showed that sorption causes a preferential removal of aromatic and carboxyl C from the solution, whereas alkyl‐C accumulates in the solution. No change was observed for O‐alkyl C. The DRIFT spectra of sorbed total DOM and AHS showed a relative increase of the band intensity of carboxyl groups compared to DOM in the initial solution, confirming the importance of those groups for the sorption to mineral surfaces. The spectra also indicated reactions of carboxyl groups with metals at the mineral surfaces. The extent to which the carboxyl groups are bound depended on the surface coverage with DOM and the type of mineral.
Linewidth of Low-Field Electrically Detected Magnetic Resonance of Phosphorus in Isotopically Controlled Silicon

The linewidth of the low-field electrically detected magnetic resonance (LFEDMR) of phosphorus electrons in silicon is investigated using samples with various 29Si nuclear spin fractions and is compared to that of X-band electron paramagnetic resonance (EPR). The linewidths of LFEDMR and EPR are the same even though LFEDMR signals are obtained based on spin-dependent recombination, suggesting that the interaction between electron spins of phosphorus and recombination centers is strong enough for the LFEDMR detection but weak enough not to affect the linewidths. This favorable balance makes LFEDMR an attractive method to elucidate the low-field behavior of paramagnetic defects in semiconductors.
Surface Tension Measurements for Four 1-Alkyl-3-methylimidazolium-Based Ionic Liquids with Hexafluorophosphate Anion

Air−liquid interfacial surface tension measurements were performed on four 1-alkyl-3-methylimidazolium-based ([Cnmim], n = 3, 4, 6, 8) ionic liquids at 15 temperatures from (287 to 353) K at atmospheric pressure. To validate the accuracy of the results, the Wilhelmy plate method and the du Nouy ring method were employed in parallel using the Krűss K100MK2 tensiometer. At each temperature, from 33 to 55 Wilhelmy plate and from 10 to 30 du Nouy ring individual readings were taken in most cases. The surface tension average values at particular temperatures are presented with estimated overall standard uncertainty of 0.05 mN·m−1. An empirical surface tension−temperature equation has been developed describing the temperature dependence of each ionic liquid surface tension. To the 69 up-to-now published surface tension values of the above-mentioned four ionic liquids, the present study adds an additional 102 data points representing means calculated from about 3000 individual surface tension readings that altog.
Chemical Synthesis and Characterization of α-N-Octanoyl and Other α-N-Acyl Colistin Nonapeptide Derivatives

Eight α-N-acyl colistin nonapeptide derivatives including three aliphatic, four aromatic and one alicyclic derivatives were synthesized by the reaction of colistin nonapeptide with corresponding acid chlorides. This acylation reaction was carried out under the condition kept restrictedly at pH 5,0 in order to introduce an acyl group only to α-amino group but not to γ-amino group existing in a colistin nonapeptide molecule. Synthetic method and several physico-chemical natures of these acyl colistin nonapeptide derivatives are given in this paper.All of the acylated derivatives thus synthesized exhibited characteristic antimicrobial activities. Antimicrobial spectra were substantially based upon a gram-negative type and not so much altered by chemical structures of acyl groups which were considerably differentiated from each other such as cyclic or chain form. Thus, more possible response of carbon size than its structure to the antimicrobial effectiveness was inferred. In spite of almost no toxicity and f.
Nitrogen loss from coffee agroecosystems in Costa Rica : leaching and denitrification in the presence and absence of shade trees

Coffee (Coffee arabica L.) management in Costa Rica is changing from traditional agroecosystems, where coffee is grown beneath a tree overstory, to management systems where shade trees are removed and N fertilizer is applied at high rats (ca. 300 kg N ha -1 yr -1 ). Although fertilization increases coffee bean production, it also increases the potential for substantial loss of N to groundwater and the atmosphere. We invatigated NO 3 - leaching and the factors controlling denitrification in shaded and unshaded coffee plantations in the Central Valley of Costa Rica; both plantation types were fertilized with 300 kg N ha -1 yr -1 . Nitrate leaching was quantified using porous ceramic cup lysimeters placed 60 cm below the soil surface. Losses were estimated by multiplying the soil water NO 3 - concentration by the monthly soil water excess, determined as the difference between precipitation and actual evapotranspiration. In addition, a laboratory experiment was conducted to investigate the influence of NO 3 - , C, and O 2 availability on N 2 O production and total denitrification (N 2 O-N+N 2 -N). Annual leaching losses of NO 3 - were almost three times greater in unshaded plantation (24 kg NO 3 - -N ha -1 yr -1 ) than those in shard plantations (9 kg ha -1 yr -1 ). In contrast, mean total denitrification rates in control soil samples from shaded plantations were 60% higher (732 μg N 2 O-N kg -1 d -1 ) than in unshaded plantations (455 μg N 2 O-N kg -1 d -1 ). Carbon additions elicited the largest increase in denitrification, generating nearly a threefold increase (+C=8396 μg N 2 O-N kg -1 d -1 ; -C=2985 μg N 2 O-N kg -1 d -1 ) in both plantation types. Anaerobic conditions also significantly increased denitrification (+O 2 =4331 μg N 2 O-N kg -1 d -1 ; -O 2 =6656 μg N 2 O-N kg -1 d -1 ). In both plantation types, the potential for N loss via NO 3 - leaching was small compared with that for gaseous N loss
Effect of Osmotic Pretreatment on Hot Air Drying Kinetics and Quality of Chilean Papaya (Carica pubescens)

The effect of osmotic pretreatment on the mass transfer kinetics and quality of dried rehydrated Chilean papaya was researched. Osmotic treatments were sucrose solutions of 40, 50, and 60% w/w and dried at 60°C; non-pretreated samples were dried at different temperatures (40, 60, and 80°C). Quality parameters were analyzed: proximal composition, rehydration ratio, water-holding capacity, color, vitamin C content, firmness, and microstructure. Non-pretreated samples showed a clear turgor loss, color loss. and low ascorbic acid retention when rehydrated. Osmotic pretreatment improved the quality of rehydrated papayas, showing higher ascorbic acid retention and best firmness and color. Microstructure is better preserved in the pretreated papayas than in the non-pretreated samples, although this difference is minimal.
Identifying Alternative Conceptions of Chemical Kinetics among Secondary School and Undergraduate Students in Turkey.

This study identifies some alternative conceptions of chemical kinetics held by secondary school and undergraduate students (N = 191) in Turkey. Undergraduate students who participated are studying to become chemistry teachers when they graduate. Students’ conceptions about chemical kinetics were elicited through a series of written tasks and individual interviews. Several alternative conceptions exhibited by secondary school students persisted among undergraduates, indicating the persistence of such alternative conceptions. The results suggest that students’ lack of understanding in thermodynamics and chemical equilibrium significantly influences their conceptions about chemical kinetics. Implications for instructional approaches particular to chemical kinetics are discussed.
Seasonal variations in aerosol particle composition at the puy-de-Dôme research station

Abstract. Detailed investigations of the chemical and microphysical properties of atmospheric aerosol particles were performed at the puy-de-Dome (pdD) research station (1465 m) in autumn (September and October 2008), winter (February and March 2009), and summer (June 2010) using a compact Time-of-Flight Aerosol Mass Spectrometer (cToF-AMS). Over the three campaigns, the average mass concentrations of the non-refractory submicron particles ranged from 10 μg m−3 up to 27 μg m−3. Highest nitrate and ammonium mass concentrations were measured during the winter and during periods when marine modified airmasses were arriving at the site, whereas highest concentrations of organic particles were measured during the summer and during periods when continental airmasses arrived at the site. The measurements reported in this paper show that atmospheric particle composition is strongly influenced by both the season and the origin of the airmass. The total organic mass spectra were analysed using positive matrix factorisation to separate individual organic components contributing to the overall organic particle mass concentrations. These organic components include a low volatility oxygenated organic aerosol particle (LV-OOA) and a semi-volatile organic aerosol particle (SV-OOA). Correlations of the LV-OOA components with fragments of m/z 60 and m/z 73 (mass spectral markers of wood burning) during the winter campaign suggest that wintertime LV-OOA are related to aged biomass burning emissions, whereas organic aerosol particles measured during the summer are likely linked to biogenic sources. Equivalent potential temperature calculations, gas-phase, and LIDAR measurements define whether the research site is in the planetary boundary layer (PBL) or in the free troposphere (FT)/residual layer (RL). We observe that SV-OOA and nitrate particles are associated with air masses arriving from the PBL where as particle composition measured from RL/FT airmasses contain high mass fractions of sulphate and LV-OOA. This study provides unique insights into the effects of season and airmass variability on regional aerosol particles measured at an elevated site.
Influence of particle size distribution on the performance of fluidized bed reactors

This paper reviews recent results obtained in our laboratory and elsewhere which show the importance of particle size distribution (PSD) in fluidized beds. Fines content in itself, often used as a descriptor, is not a sufficient parameter to characterize the PSD effect. Broadening the PSD affects gas flow through the dense phase, produces smaller bubbles, leads to more particles in the dilute phase and causes earlier transition to the turbulent hydrodynamic regime of fluidization. Chemical conversion is therefore enhanced by broadening the PSD, and the enhancement increases when the bed operates in the turbulent regime.
Measurement of intensity ratio of nitrogen bands as a function of field strength

The ratio of intensities of the first negative system and the second positive system of nitrogen as a function of the electric field strength was experimentally determined in atmospheric-pressure air. The non-self-sustained discharge was excited in a parallel-plane gap using the radiation of a pulsed laser. The field strength was varied in the range of 135–285 Td. The peculiarities of the measurement and data processing of signals of very low intensity are described. The results are compared with the theoretical predictions of other authors.
A single-crystal neutron diffraction study of hambergite, Be2BO3(OH,F)

Abstract The crystal chemistry and crystal structure of hambergite from the Anjanabonoina mine, Madagascar [Be2BO3(OH)0.96F0.04, Z = 8, a = 9.762(2), b = 12.201(2), c = 4.430(1) Å, V = 527.6(2) Å3, space group Pbca], were reinvestigated by means of electron microprobe analysis in wavelength-dispersive mode, secondary-ion mass spectrometry, single-crystal X-ray and neutron Laue diffraction. Chemical analyses show only a small amount of F (0.7-0.8 wt%, approximately 0.04 atoms per formula unit) substituting OH and no other substituent at a significant level. An anisotropic neutron structural refinement has been performed with final agreement index R1 = 0.0504 for 76 refined parameters and 1430 unique reflections with F0 > 4σ(F0). The geometry of the hydroxyl group and hydrogen bonding in hambergite is now well defined: (1) only one independent H site was located and the O4-H distance, corrected for “riding motion,” is ∼0.9929 Å; (2) only one hydrogen bond appears to be energetically favorable, with a symmetry-related O4 as acceptor and with O4···O4 = 2.904(1) Å, H···O4 = 1.983(1) Å, and O4-H···O4 = 157.5(1)°. In other words, O4 sites act both as donor and as acceptor of the hydrogen bond, with a zigzag chain of H-bonds along [001]. The hydrogen-bonding scheme in hambergite found in this study is consistent with the pleochroic scheme of the infrared spectra previously reported, with two intensive modes ascribable to stretching vibrations of the hydroxyl group, at 3415 and 3520 cm-1, respectively. The two modes suggest at least two distinct hydrogen-bonding environments, ascribable to the presence of oxygen and fluorine at the acceptor site.
Monte Carlo study of liquid crystal phases of hard and soft spherocylinders

We report on a Monte Carlo study of the liquid crystal phases of two model fluids of linear elongated molecules: (a) hard spherocylinders with an attractive square-well (SWSC) and (b) purely repulsive soft spherocylinders (SRS), in both cases for a length-to-breadth ratio L*=5. Monte Carlo simulations in the isothermal–isobaric ensemble have been performed at a reduced temperature T*=5 probing thermodynamic states within the isotropic (I), nematic (N), and smectic A (Sm A) regions exhibited by each of the models. In addition, the performance of an entropy criterion to allocate liquid crystalline phase boundaries, recently proposed for the isotropic–nematic transition of the hard spherocylinder (HSC) fluid, is successfully tested for the SWSC and the SRS fluids and furthermore extended to the study of the nematic–smectic transition. With respect to the more extensively studied HSC fluid, the introduction of the attractive square well in the SWSC model brings the I–N and N–Sm A transitions to higher pressur.
Poly(hexamethylene terephthalate-co-caprolactone) Copolyesters Obtained by Ring-Opening Polymerization

A set of aromatic−aliphatic copolyesters were synthesized by ring-opening polymerization of hexamethylene terephthalate (HT) cyclic oligomers and ϵ-caprolactone monomer (CL) at 175 °C using Sb2O3 catalyst. A hexamer- and heptamer-enriched cyclic fraction isolated from the product obtained in the cyclo-depolymerization of poly(hexamethylene terephthalate) (PHT) was used. Ring-opening copolymerizations were conducted for HT to CL feed ratios covering the whole range of compositions and for increasing periods of reaction time. The comonomer contents of the resulting copolyesters were similar to those of their respective feeds, and did not vary with reaction time. In contrast, the copolyester microstructure evolved from block to random as the reaction progressed. The thermal properties of the copolyesters was apparently dependent on both composition and microstructure, and therefore changed with reaction time. The hydrolysis of the copolyesters in simulated physiological medium with and without addition of li.
A density functional theory study of complex species and reactions of Am(III)/Eu(III) with nitrate anions

Complex behaviours of americium(III) and europium(III) with nitrate anions have been studied using density functional theory and small-core quasi-relativistic effective core potential. The structural parameters of a series of hydrated and nitrate complexes of Am(III) and Em(III) are probed and compared to available EXAFS studies. The thermodynamic stability of these species is calculated by simulating related complexation reactions both in the gas phase and aqueous solution. For taking into account the solvent effect, both the solvation model density (SMD) implicit solvent model and the conductor-like screening model (COSMO) are adopted for comparison. From our calculations, the octa–aqua and non-aqua species of Am(III) and Eu(III), [M(H2O)8,9]3+ (M = Am, Eu), form square antiprism and trigonal prism structures, respectively. In the presence of rich-enough nitrate ions, at most three nitrate anions can chelate to Am(III)/Eu(III) ions in a bidentate fashion in the first coordination shell, owing to the strong Coulomb interactions. From the changes of the Gibbs free energy for complexation reactions, , the bidentate complexes are more favourable than the monodentate ones with the same coordination numbers. The comparison of ionic exchange reactions further suggests a stronger coordination ability and harder acidity of Eu(III) than Am(III). The SMD and COSMO predict the same trend in solvent effect, whereas the latter seems to give obviously lower changes of the Gibbs free energy.
Theoretical study on the weakly-bound complexes in the reactions of hydroxyl radical with saturated hydrocarbons (methane, ethane, and propane)

Weakly bound reactant and product complexes in the hydrogen abstraction reactions of an OH radical with CH 4 , C 2 H 6 , and C 3 H 8 are investigated with ab initio molecular orbital methods. The calculated binding energy of the CH 4 and OH reactant complex at CCSD(T)/aug-cc-pVTZ (aug-cc-pVDZ) levels is 0.54 (0.74) kcal/ mol. The zero-point vibrational energy correction at MP2 level with the corresponding basis sets reduces the binding energy to 0.16 (0.08) kcal/mol, which is substantially smaller than the recent experimental estimation (about 0.60 kcal/mol). A product complex for the CH 4 + OH system, which is more stable than the reactant complex, has the binding energy of 0.77 (0.79) kcal/mol at CCSD(T)/aug-cc-pVTZ (aug-cc-pVDZ) levels with MP2 zero-point energy corrections. The reactant and product complexes are also found for the C 2 H 6 + OH and C 3 H 8 + OH reactions at the CCSD(T)/aug-cc-pVDZ level of theory. The binding energies tend to increase with the number of carbon atoms of the hydrocarbon. The reaction rates and their temperature dependence are estimated, and they are more than 1 order of magnitude larger than the experimentally reported values.
Syntheses and crystal structures of trigonal rare-earth dioxymonocyanamides, Ln2O2CN2 (Ln = Ce, Pr, Nd, Sm, Eu, Gd)

Abstract New compounds, trigonal rare-earth dioxymonocyanamides Ln 2 O 2 CN 2 , were synthesized by heating Ln 2 O 3 ( Ln = Nd, Sm, Eu, Gd), Ce 2 (CO 3 ) 3 · 8H 2 O, or Pr 6 O 11 in the presence of carbon under flowing ammonia gas. The crystal structures of Ln 2 O 2 CN 2 were refined by the Rietveld method using X-ray diffraction data. The Ln 2 O 2 CN 2 compounds crystallize in the trigonal space group P 3 m 1, with a and c parameters varying from 3.9442 to 3.7812 A and from 8.3609 to 8.2311 A, respectively, as Ln atoms change from Ce to Gd. A choice of the space group was done assuming that the structure of Ln 2 O 2 CN 2 is like that of Ln 2 O 2 S. In this paper, structural parameters for both Ce 2 O 2 CN 2 and Gd 2 O 2 CN 2 are not reported because the parameters for the atoms did not converge to reasonable values. These compounds have the layer structures which consist of the Ln 2 O 2+ 2 layers with the interlayer CN 2− 2 ions. The Ln 2 O 2+ 2 layers are piled perpendicular to the c axis and the linear cyanamide ions, − N⩞C⩞N − , are inserted parallel to the c axis.
Fine Needle Aspiration Cytology of Lung Masses, benefits, precautions and complications.

Background: Pulmonary masses represent a great challenge for diagnosis. Fine Needle Aspiration Cytology (FNAC) is one of the diagnostic methods which was used since long time.Objectives: To concern on Fine Needle Aspiration Cytology of pulmonary masses regarding benefits, precautions and patient’s preparation to avoid possible complications.Patients and Methods: A prospective study is carried out from December 2008 to July 2015 on 45 patients presented with pulmonary masses to the Department of the thoracic and vascular surgery at Al-Yarmook teaching hospital and from the private sector. A Fine Needle Aspiration Cytology was done for them under local anesthesia as an outpatient procedure.Results: 40 patients (88.9%) got accurate results of diagnosis as different types of malignancies. Five patients (11.1%) got inconclusive results. No mortality reported. Complications like Pneumothorax was occurred in three patients (6.7 %), Haemoptysis in 14 patients (31%) and mild chest pain in 13 patients (29%). Conclusion: FNAC is relatively safe and valuable method to diagnose pulmonary mass lesions and to categorize them for better subsequent management either surgical or by chemotherapy but the patients must be prepared well and the doctor who intend to do FNAC either being trained to deal with possible complications or backed up with a thoracic unit.
Biomimic Superhydrophobic Surface with High Adhesive Forces

Superhydrophobic polydimethylsiloxane (PDMS) surfaces that contain microbinary and nanobinary structures with a water contact angle (CA) of >150° are created by duplicating the microstructures of a rose petal. The resulting surface has the same microstructures and high adhesive property as a rose petal; the water CA of the surface is as high as 154.3°. Interestingly, this surface can hold water droplets through the use of very strong adhesive forces, and the maximum adhesive force is ~63.8 μN. Furthermore, the resulting surface has another important property; it shows superhydrophobic property in a wide range of pH values from 1.07 to 13.76. Therefore, it is believed that the as-prepared surface can be used in the fabrication of chemical engineering materials, microfluidic devices, and the transportation of a small amount of corrosive liquids.