Miracle-dz/UniFAR-FTUs huggingface dataset:
Removal of Pb(II) from aqueous solution by mesoporous silica MCM-41 modified by ZnCl2: kinetics, thermodynamics, and isotherms

A new hybrid nanostructured sorbent ZnCl2-MCM-41, was synthesized by a post-synthesis method in toluene as the solvent. To characterize the sorbent, a number of methods were applied, including X-ray diffraction (XRD), nitrogen adsorption–desorption isotherm, Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Characterization demonstrated that the sorbent particles are of semi-spherical shape, nanostructured with a 754 m2 g−1 surface area and a 2.86 nm pore diameter. The Pb(II) removal depended on several parameters, including the pH of solution, temperature, initial Pb(II) concentration, sorbent dosage, ionic strength, and the amount of ZnCl2 loaded on the MCM-41 surface. The results showed that the pseudo-second-order model describes the kinetics of sorption better than the pseudo-first-order model. The adsorption continuously increased in the pH range of 2.0–7.0, beyond which the adsorption could not be carried out due to the precipitation of the metal ions. The adsorbent had a considerably high Langmuir monolayer capacity of 479 mg g−1. The adsorption process was exothermic at ambient temperature and the computation of the parameters ΔG°, ΔH°, and ΔS° indicated the interactions to be thermodynamically favorable.
Physical and Chemical Interactions in Melt Mixed Nylon‐6/EVOH Blends

Abstract Nylon‐6 (Ny‐6) and ethylene‐vinyl alcohol copolymer (EVOH) binary blends were prepared in various compositions via dynamic melt blending. In addition, 50/50 blends of EVOH with nylon‐6/6.9 (Ny6/6.9) and nylon‐11 (Ny‐11) were prepared to study the effect of nylon type on the structuring process under melt mixing. The phase morphology and the crystallization behavior of the blends were investigated using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The insoluble content was studied by solvent extraction. The mixing torque was found to increase with mixing time for intermediate Ny‐6 contents, indicating chemical reactions and hydrogen bonds formation between the polymers. Based on FT‐Raman spectroscopy chain extension is suggested to be the main chemical reaction between EVOH and Ny‐6. The different interaction levels obtained for the Ny‐6/EVOH blends affect their properties. The melting temperature of one component decreases as the content of the other component is increased. EVOH has lower crystallization degree when its content is lower; conversely, Ny‐6 crystallinity increases for some compositions compared to the neat polymer. Storage modulus and glass transition temperature values of the blends are between those of the neat polymers according to composition. However, positive deviation was obtained for the 50/50 Ny‐6/EVOH blend owing to the chemical reaction between the polymers. SEM micrographs of fractured surfaces exhibit quite uniform, almost as a single‐phase morphology, indicating high interaction level between the polymers. SEM/EDS of etched samples revealed that the dispersed particles in the blends are on a submicron scale.
Multilayer TiO2–Nanotube Formation by Two-Step Anodization

In this work we report on the growth of a closely stacked double layer of a self-organized TiO 2 nanotubes. For that we first anodize Ti in acidic electrolyte containing hydrofluoric acid to form thin nanotube layers. Afterwards we start a second anodization in a different electrolyte, a glycerol/NH 4 F mixture. This procedure allows us to grow the second layer directly underneath the first one. From scanning electron microscopy and transmission electron microscopy investigations we revealed that the second growth occurs via the tube bottoms of the first layer. These stacked multilayers generate new possibilities to vertically tailor the properties of the self-organized TiO 2 nanotube layers.
The Pre-FOMC Announcement Drift: More Recent Evidence

We had previously documented large excess returns on equities ahead of scheduled announcements of the Federal Open Market Committee (FOMC)? the Federal Reserve? s monetary policy-making body? between 1994 and 2011. This post updates our original analysis with more recent data. We find evidence of continued large excess returns during FOMC meetings, but only for those featuring a press conference by the Chair of the FOMC.
Influence of the COOH and COONa groups and crosslink density of poly(acrylic acid)/ montmorillonite superabsorbent composite on water absorbency

A novel poly(acrylic acid)/montmorillonite superabsorbent composite with a water absorbency of 1100 times its own weight was synthesized by the graft copolymerization of acrylic acid with a cross-linking agent in the presence of montmorillonite ultrafine powder. The influence of the amount of crosslinker and montmorillonite on water absorbency has been investigated. It was found that a crosslinker concentration of 0.03 wt% and 30 wt% montmorillonite gave the best results. The collaborative absorbent effect of sodium carboxylate and carboxylic acid groups was superior to that of sodium carboxylate or carboxylic acid groups alone, and the composite with a ratio of about 2/3 for sodium carboxylate to carboxyl acid groups possessed the highest water absorbence. © 2001 Society of Chemical Industry
Modelling of the Extraction and Back‐Extraction Equilibria of Zinc from Spent Pickling Solutions

Abstract This work reports the study of the chemical equilibria of the extraction and back‐extraction of zinc from spent pickling solutions. Tributyl phosphate was used as a selective extractant and service water as a back extraction agent. Feed solutions had an average composition of 6.4 M Cl−, 1.2 M Zn+2, 1.7 M Fe+2 and traces of other heavy metals i.e., Pb, Ni, Cu, Mn. Under the experimental conditions the ion ZnCl4 2− was the predominant zinc species in feed. A careful experimental design was performed obtaining the equilibria mathematical models and parameters, KEX=0.137 (mol/L)−4, and KBEX=1.46 [−].
Effects of electron beam irradiation on antioxidants in commercial polyolefins: Determination and quantification of products formed

The influence of electron beam irradiation on antioxidants present in food packaging materials (OPP and LDPE) was studied. After irradiating the materials at dose levels of 2, 5,10 and 25 kGy, we have shown a partial disappearance of the antioxidant (Irganox 1010, Irganox 1076 and Irgafos 168) and a release of three compounds resulting from the antioxidants degradation related to the irradiation dose. Two of these degradation compounds have been analysed quantitatively: the 2,4-di-tert. -butyl-phenol and the 2,6-di-tert -butyl-p-benzoquinone. The third compound is a phosphate resulting from a phosphite stabilizer (Irgafos 168).
Reactive ion etching of GaAs, AlGaAs, and GaSb in Cl2 and SiCl4

High rate (≤10 μm min−1 ) etching of GaAs, AlxGa1−x As, and GaSb in Cl2/Ar or SiCl4/Ar discharges is reported. The etching was investigated as a function of discharge pressure, power density and composition, and changes in the etching rate of AlxGa1−xAs when SF6 was added to the gas mixtures. Highly anisotropic etching was achieved with SiCl4 for all materials, whereas a greater degree of chemical etching was evident with Cl2. Provided self‐biases were ≤50 V, excellent Schottky diode characteristics were exhibited by TiPtAu contacts on SiCl4 or Cl2 etched GaAs surfaces. Energetic‐ion bombardment caused carrier compensation up to 2200 A from the surface in n‐type (1017 cm−3 ) GaAs, with this depth being less for lower self‐biases. Photoluminescence decreases of 2–25 times were observed after reactive ion etching of GaAs for both types of discharge. Chlorine residues were typically present to a depth of <20 A after etching, with cleaner surfaces obtained with SiCl4 than with Cl2.
Development of water‐blown bio‐based thermoplastic polyurethane foams using bio‐derived chain extender

Water-blown bio-based thermoplastic polyurethane (TPU) formulations were developed to fulfill the requirements of the reactive rotational molding/foaming process. They were prepared using synthetic and bio-based chain extenders. Foams were prepared by stirring polyether polyol (macrodiol), chain extender (diol), surfactant (silicone oil), chemical blowing agent (distilled water), catalyst, and diisocyanate. The concentration of chain extender, blowing agent, and surfactant were varied and their effects on foaming kinetics, physical, mechanical, and morphological properties of foams were investigated. Density, compressive strength, and modulus of foams decrease with increasing blowing agent concentration and increase with increasing chain extender concentration, but are not significantly affected by changes in surfactant concentration. The foam glass-transition temperatures increase with increasing blowing agent and chain extender concentrations. The foam cell size slightly increases with increasing blowing agent content and decreases upon surfactant addition (without any dependence on concentration), whereas chain extender concentration has no effect on cell size. Bio-based 1,3-propanediol can be used successfully for the preparation TPU foams without sacrificing any properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Relationships between Numbers of Microbial Communities in Polish Agricultural Soils and Properties of these Soils, paying Special Attention to Xerophilic/Xerotolerant Fungi

Our study was conducted with seven typical Polish soils very different in their physical and chemical features and fertility (a Phaeozem, an Eutric Fluvisol, three Eutric Cambisols, and two Dystric Cambisols). Samples of the soils were taken from a plot experiment established in Pulawy at the end of the 19 th century and cultivated only by hand tillage. Correlation analyses of the results obtained suggest that soil microorganisms differing in their water requirements were associated with different soil environments: bacteria with small particles and small pores usually filled with water, nonxerophilic fungi with medium particles and medium pores which are usually the region of near the air-water interface, and xerotolerant/xerophilic fungi (especially penicillia) predominantly with big particles and big pores usually filled with air. Moreover, CFU of xerotolerant/xerophilic fungi and particularly formulated indices of xerotolerance of the soil fungal communities (in contrast to CFU of bacteria), were negatively correlated with water content, SOM content, soil pH, and an index of soil quality.
Factors Determining the Rate of Dissolution of Metal Oxides in Acidic Aqueous Solutions

Empirical rules governing the dissolution rates of oxides of the transition metals in acidic solutions containing redox systems are exemplified by the dissolution of CoO. Deviations from these rules shown during the dissolution of NiO (and partly of CuO) are discussed. The presence of organic complexing agents in the solution enhances in general the rate of dissolution of metal oxides. In the case of the iron oxides, induction periods of slow dissolution have been observed. An interpretation of these induction periods is based on a particular formation mechanism of metal chelates. The combined action of redox potential and complexing agent in the solution leads to a decrease of the dissolution rates, due possibly to a blocking of crystal surface sites by constituents of the redox couple and the complexing agent.
Utilization of Urban and Pulping Wastes to Produce Synthetic Fuel via Pyrolysis

Major byproducts of delignification processes of lignocellulosic biomass include lignin degradation products. Lignin and its degradation products have fuel values. The yields of liquid and gaseous products from the solid waste pyrolysis increase from 23.8 to 49.7% with temperatures increasing from 584 to 683 K. The yields of liquid and gaseous products from the black liquor pyrolysis increase from 7.3 to 55.0% with temperatures increasing from 500 to 800 K. The yields of liquid and gaseous products from pyrolysis of the solid waste and black liquor samples increase with increasing temperature. This increase is very sharp for the yields of liquid products from the solid waste at the same temperature range.
Interactive Effects of Lanthanum and Cadmium on Plant Growth and Mineral Element Uptake in Crisped-Leaf Mustard Under Hydroponic Conditions

Plant growth and mineral element accumulation in Brassica juncea var. crispifolia (crisped-leaf mustard) under exposure to lanthanum (La) and cadmium (Cd) were studied by employing a hydroponic experiment with a complete two-factorial design. Four levels of La (0.05–5.0 mg L−1) and two levels of Cd (1.0 and 10.0 mg L−1) were used in this experiment. Lanthanum did not improve plant growth in this experiment. Addition of La (≥ 1.0 mg L−1) or Cd (≥ 10 mg L−1) to the solution inhibited root elongation. Lanthanum treatments reduced accumulations of iron (Fe), manganese (Mn), and zinc (Zn) in roots, and Mn in shoots. Lanthanum at ≥ 1.0 mg L−1 limited the Cd translocation from roots to shoots and thus decreased the accumulation of Cd in shoots. Cadmium had no influence on La accumulations in roots, but inhibited the accumulation of La in shoots. The study results suggest that applications of rare earth elements in vegetables would be potentially risky to human health.
The silane depletion fraction as an indicator for the amorphous/crystalline silicon interface passivation quality

In silicon heterojunction solar cells, thin amorphous silicon layers passivate the crystalline silicon wafer surfaces. By using in situ diagnostics during plasma-enhanced chemical vapor deposition (PECVD), the authors report how the passivation quality of such layers directly relate to the plasma conditions. Good interface passivation is obtained from highly depleted silane plasmas. Based upon this finding, layers deposited in a large-area very high frequency (40.68 MHz) PECVD reactor were optimized for heterojunction solar cells, yielding aperture efficiencies up to 20.3% on 4 cm2 cells.
Rational design and SERS properties of side-by-side, end-to-end and end-to-side assemblies of Au nanorods

By taking advantage of the anisotropy of AuNRs, we design different bifunctional PEG molecules to selectively bind to either the end or side face and simultaneously protect other faces of individual AuNRs. In this way, we successfully achieve orientation-controllable assemblies of AuNRs into side-by-side (SS), end-to-end (EE) and end-to-side (ES) orientations based on the electrostatic interaction between carboxylic PEG and CTAB capping on AuNRs. Furthermore, we find that the different orientations of assembled motifs in these three types of AuNRs assemblies exhibited different near field coupling between the surface plasma of the neighboring AuNRs, leading to different surface-enhanced Raman signals. Undoubtedly, the current rational design of oriented assembly can be potentially useful for directing anisotropic nanoparticles into well-defined orientations, which provides a powerful route in designing families of novel nanodevices and nanomaterials with programmable electrical and optical properties.
Eley–Rideal diffusion limited reactions over rough surface

The effect of surface roughness on Eley–Rideal diffusion limited reactions is studied. The rough surfaces are generated using a random deposition model and a random deposition with diffusion model. The former model generates the rough surface with no correlations between the heights of different columns whereas the latter generates the rough surface with correlations between the heights of different columns. Multifractal scaling analysis has been carried out on the reaction probability distribution. The reaction probability distribution has a wider range for the surface of random deposition than that of random deposition with diffusion.
Comparative Analysis of Process of Diffusion of Interstitial Oxygen Atoms and Interstitial Hydrogen Molecules in Silicon and Germanium Crystals: Quantumchemical Simulation

A theoretical modeling and comparative analysis of the process of diffusion of the interstitial oxygen atoms and interstitial hydrogen molecules (H 2 ) in silicon and germanium crystals at normal and hydrostatic pressure (HP) have been performed. The process of diffusion of particle with a strong interaction with a crystal lattice (interstitial oxygen atom) is a cooperative process. Three nearest Si (Ge) atoms of crystal lattice are involved in an elementary oxygen jump from a bond-center site to another bond-center site along a path in the (110) plane. It is precisely their optimum position (corresponding to a local minimum of the crystal total energy) determines the value of the diffusion parameters of an interstitial oxygen atom in silicon and germanium crystals. In a sense, the diffusion process may be considered as a diffusion process of qwasiparticle – (Oi+3Si). In the case of a particle weakly interacting with a crystal lattice (interstitial hydrogen molecules) we come up against the opposite case – the diffusion of H 2 is not a cooperative process. The calculated values of the activation energy and pre-exponential factor for an interstitial oxygen atom δE(Si) = 2.59 eV, δE(Ge) = 2.05 eV, D 0 (Si)= 0.28 cm 2 s −1 , D 0 (Ge)= 0.39 cm 2 s −1 and interstitial hydrogen molecule δE(Si) = 0.79 – 0.83 eV, δE(Ge) = 0.58 – 0.62 eV D 0 (Si)= 7.4 10 −4 cm 2 s −1 , D 0 (Ge)= 6.510 −4 cm 2 s −1 are in an excellent agreement with experimental ones and for the first time describe perfectly an experimental temperature dependence of an interstitial oxygen atom and hydrogen molecules diffusion constant in Si crystals.
Modeling the cyclopolymerization of diallyl ether and methyl α-[(allyloxy)methyl]acrylate

The free-radical cyclopolymerization of diallyl ether (1) and methyl α-(allyloxymethyl)acrylate (2) has been modeled with the B3LYP/6-31G* methodology, by making use of model compounds for the growing radicals. The cyclization of both monomers is exo, with activation barriers of 5.33 and 9.82 kcal/mol, respectively. To account for the polymerizabilities of these monomers, competing reactions have also been modeled. Although both monomers have a lower barrier for homopolymerization than for cyclization, cyclization dominates due to entropy. This explains the high cyclopolymerization vs. homopolymerization of monomer 2, although its monofunctional counterpart has been reported to homopolymerize well. It has also been shown that the degradative chain transfer by H-abstraction from the allylic carbon is not effective with this monomer. Poor cyclopolymerization of the monomer 1 has been demonstrated by modeling the degradative chain transfer by H-abstraction from the allylic carbon, which has been shown to compete very efficiently with polymerization reactions. Additionally, intermolecular propagation reaction has been shown to be facile due to cyclization, since the attacking monomer adopts a cyclic structure. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Statistical Treatment of Data from Student Teaching Evaluation Questionnaires.

The objectives of this analysis were: 1) To determine whether the differences in results for lecture course sections were statistically significant; 2) To examine the effect of several factors other than teaching skill of the lecturer in order to learn the extent to which such factors mighty have to be taken into account in interpreting questionnaire results; 3) To develop for each question used, "baseline" data with which results for an individual lecturer could be compared.
Analytical modeling of direct tunneling current through gate stacks for the determination of suitable high-k dielectrics for nanoscale double-gate MOSFETs

Gate-leakage current reduction is the key motivation for the replacement of traditional SiO2 gate insulator with alternative gate dielectrics. In this work, a guideline for the determination of the suitable high-k candidate was reported in the case of a SiO2/high-k gate stack in a nanoscale double-gate (DG) MOSFET. Analytical models of direct tunneling gate leakage current with SiO2 as an interfacial layer have been considered. Using these models, the most promising high-k materials for different conditions were predicted, considering the effects of equivalent oxide thickness (EOT), gate leakage current, electron effective mass, dielectric constant-k value, barrier height and interfacial oxide thickness.
Banana Frozen Yoghurt from Camel Milk

This study is conducted in the dairy laboratory of the faculty of Agricultural Technology and Fish Sciences, Al-Neelain University. The objective of this study was to investigate the possibility of manufacture frozen yoghurt from camel milk with banana flavor and investigate the suitable levels of banana which were 10, 12 and 14%. pH value, fat%, total solids, solids not fat, specific gravity, overrun, sensory properties and acceptability were studied. The result of chemical analysis showed no significant differences between the three levels of banana on pH value, fat %, total solids, solids not fat at p>0.05, while the differences were significant in specific gravity and overrun. The panel test showed that there was no significant differences between three levels of banana on sensory evaluations at p>0.05. 14% obtained the best score.
Post harvest quality of papaya storage under refrigeration

The purpose of this study was to evaluate the post harvest quality and shelf storage of 'Tainung 01' papaya fruit stored under different refrigerated temperatures. The fruits were from a commercial cultivation in the district of Barauna-RN-Brazil. The fruits were storied in cold rooms at 8o, 10o and 12oC ± 1oC and 90 ± 5% RH during the period of 7, 14, 21 e 28 days. After each period, the fruits were put at environmental conditions (20o ± 1oC 60 ± 5% RH) where was simulated a shelf life period for seven days. Then, the papayas were analyzed in relationship to the external and internal appearance, coloration of the skin, mass loss and pulp firmness. The best evaluation for quality maintenance and increase the post harvest usefue life of the ' Tainung 01' papaya was observed in the fruits submitted to 10°C, 90 ± 5% RH up to 20 days, with good extern and interns appearance (notes above 3,0), development of the yellow coloration in the skin, firmness of superior pulp of 20 N and loss of mass of 7%. The submitted fruits at 8°C and to 10°C, 90 ± 5% RH developed symptoms of chilling injury after 21 days of storage, becoming worse with the extension of the storage. In the storage to 12°C, 90 ± 5% RH an accelerated ripening was observed with aqueous softening of the pulp starting from 28 days. On the 35th day, the fruits were inapt for consumption having great incidence of Colletotrichum gloeosporioides.
Recycling of Waste Poly(Ethylene Terephthalate) with Naphthalene and Neutral Water

Abstract The waste poly(ethylene terephthalate) (PET) powder dissolution/reprecipitation was carried out in a batch operation at atmospheric pressure at various temperatures ranging from 180–220°C at temperature intervals of 10°C. Particle sizes of the waste PET ranged from 50–512.5 µm and operation time, which ranged from 30–90 min, were optimized. Dissolution/reprecipitation of the waste PET was carried out in naphthalene (solvent) and neutral water (nonsolvent), respectively. Dissolution/reprecipitation of the waste PET was increased with operation time and temperature. Dissolution/reprecipitation of PET was decreased with increase in the particle size of the waste PET. The waste PET particle size and agitator speed required for complete recycling of the waste PET were also optimized. Analyses of the waste PET and the recycled PET collected after the reprecipitation process was undertaken by determination of various physical properties. The operation applied at lesser time and with cheaper solvent/nonsolvent, resulted in excellent quality of the recycled PET collected after the reprecipitation process. This process of recycling of the waste PET has an industrial significance due to most economical operation for commercialization.