Miracle-dz/UniFAR-FTUs huggingface dataset:
Molecular modeling of cellulose in amorphous state. III. An innovative elastomeric crosslink system

The flexibility of molecular structures of rubber materials was evaluated using molecular modeling techniques to develop new crosslink agents which improve deformation recovery of cellulose without significant loss of the mechanical strength. Among the studied structures Poly(propylene oxide) (PPO) pentamer appears to be the most flexible and coiled one. Our calculation results showed that, cellulose crosslinked with PPO pentamers had similar deformation recovery to that crosslinked with DMDHEU. No conformation transitions were observed in these crosslinks when cellulose models were extended to 15% strain, which is consistent with the previous result that conformation transitions in crosslinks should be avoided upon extension to achieve a good recovery on crosslinked cellulose. In addition, PPO crosslinks did not significantly affect the breaking strain of cellulose based upon the cavity volume calculations, and they helped to remove the stress concentration among cellulose chains as suggested by the results of hydrogen bonding analysis. Thus, breaking strength of cellulose might not be significantly affected by PPO crosslinks as well. The preliminary experimental results confirmed above observations. Therefore, PPO pentamer appears to be a promising elastomeric backbone structure of crosslinking agents.
A re‐examination of closed flux chamber methods for the measurement of trace gas emissions from soils to the atmosphere

The most widely used method for measuring the emission of a trace gas such as N2O from soil to the atmosphere involves the accumulation of the gas under closed chambers followed by sampling and analysis (by gas chromatography or infrared methods). These chambers can affect the gas exchange, and so improved designs have been proposed. We have tested their performance. One design includes a vent tube to allow ambient pressure fluctuations to occur also inside the chamber. We tested it against a sealed version on two different grassland sites during N2O peak emissions in spring 1997. On a welldrained soil with a fairly large air permeability vented chambers yielded fluxes as much as five times those of sealed chambers, depending on wind speed. By contrast, on a heavier and wetter soil with smaller air permeability vented chambers averaged only 88% of the fluxes observed with sealed chambers. The effects of venting cannot be explained solely on the basis of mean pressure differences inside and outside the chamber. It seems more likely that wind blowing over the vent depressurizes the chamber (Venturi effect), resulting in significant gas flow from the more permeable soil into the interior of the chamber. The opposite trend for the less permeable soil suggests that diffusion losses through the vent tube are greater than the increase in concentration due to soil gas flow. Venting can create larger errors than the ones it is supposed to overcome.
The Mechanism of the Wolff‐Kishner Reduction, Elimination, and Isomerization Reactions

The mechanism of the Wolff-Kishner reaction is discussed in the light of accumulated information about the kinetics, thermodynamics, and solvent effects of the process. Wolff-Kishner reduction under normal conditions is thought to involve the trans hydrazone anion, which, in the rate-determining step, exhibits a more or less concerted proton capture at the carbanion terminal and undergoes a solvent-induced proton loss at the nitrogen terminal. The stereochemistry of the Wolff-Kishner reduction is believed to be affected by the presence of “ortho” substituents and by a change to a nonpolar, aprotic reaction medium. The mechanism elaborated for the Wolff-Kishner reduction is extended to the Wolff-Kishner elimination and isomerization reactions. Conformational analysis of the intermediates permits correlation of the competitive reduction and elimination processes with the structures of acyclic systems.
Sensory-Chemical Relationships in Parmigiano-Reggiano Cheese

Abstract The taste and odour properties of 20 samples of Parmigiano-Reggiano cheese were individually related to their volatile and non-volatile components using partial least squares analysis as the multivariate regression technique. Odour intensity, taste fragrancy and staleness were three sensory attributes involved in significant relationships with two major chemical classes (esters and free fatty acids) and with selected volatile (short-chain branched alcohols, sulphides) and non-volatile (free amino-acids, salt) compounds. The combined set of sensory and chemical data, subjected to Principal Components Analysis, exhibited two major changes in the sensory properties of cheese, as possibly being affected by salt-controlled chemical patterns; the score-plot of the samples as regards the first two principal components showed that winter cheese was separated from cheese manufactured the rest of the year.
Dispersion and bilayer interaction of single-walled carbon nanotubes modulated by covalent and noncovalent PEGylation

Single-walled carbon nanotubes (SWNTs) covalently functionalised with polyethylene glycol (PEG) or noncovalently coated with PEGylated lipids were simulated in water and in lipid bilayers at different PEG sizes and grafting densities using coarse-grained force fields. Starting with the random position of three SWNT–PEG complexes in water, larger PEGs at higher grafting densities more significantly inhibit the aggregation of SWNTs because of larger radii of gyration and hydrodynamic radii of the SWNT–PEG complex, which influence the thickness and the wrapping extent of PEG layer. In particular, PEG-functionalised SWNTs, where PEGs are evenly grafted along the SWNT, disperse, while PEG-coated SWNTs aggregate because SWNTs are less covered by randomly adsorbed PEGylated lipids. Simulations of SWNT–PEGs in lipid bilayers show that PEG (Mw = 550 and 2000)-functionalised SWNTs bind to the bilayer surface but do not insert into the bilayer, while PEG-coated SWNTs insert into the bilayer because PEGylated lipids detach from SWNTs and mix with bilayer lipids. These findings support recent experiments at the same PEG size and density, which suggested that PEG-coated SWNTs may form bundles and thus cannot be easily excreted through the renal route, while PEG-functionalised SWNTs may remain individual and thus show more renal excretion.
Buried contact solar cells with innovative rear localised contacts

A new rear contacting scheme using low‐temperature processes to form localised contacts without the use of photolithography has been developed. It uses randomly nucleated, aluminium‐induced, localised regions of solid phase epitaxial growth of p+ silicon onto the rear surface of a wafer through a thick rear surface passivating oxide. This rear contacting technique has been applied on solar cells with front buried contacts and results have shown that a suitable ohmic contact to the rear can be formed through oxide as thick as 3000 Å and using only low temperature sintering below the eutectic temperature of silicon and aluminium. This low‐temperature sintering avoids the destruction of the interfacial oxide which has been shown to provide good surface passivation for the rear of the solar cells. Microscopic images indicate the possibility of forming p+ rear contacts with aluminium‐induced crystallisation, but without requiring any additional deposition of silicon. The source of silicon for the latter appears to be from the reduction of the silicon dioxide by the aluminium. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of Operating Conditions on PV Performance of PVA Membranes: Experimental and Neural Network Modeling

Poly (vinyl alcohol) membranes were prepared by in-situ crosslinking of poly(vinyl alcohol) with glutaraldehyde as crosslinking agent and hydrochloric acid as catalyst and used for dehydration of IPA mixtures. Effects of feed composition, operating temperature, vacuum pressure, and Reynolds number on the permeation performance of the membranes were evaluated. Eighty-nine experimental data was applied to investigate ANN modeling. A multi layered feedforward neural network was applied to model the PV membranes. Two major training algorithms and optimum number of neurons and layers were investigated. As a result, Bayesian regularization successfully predicted experimental data. Different network structures were optimized, using multi object genetic optimization algorithm. The results concluded that the network with structure composing two hidden layers performs better than the other with one hidden layer, and also there is an excellent compatibility between the experimental data and the predicted values of optimum network structure (4:3:2:2). Furthermore, the optimum network was applied to predict extrapolation data and the results showed that this network can extrapolate data as well as interpolating.
Comparative effects of biostimulation and phytoremediation on crude oil degradation and absorption by water hyacinth (Eichhornia crassipes [Mart.] Solms)

This study investigated the effects of inorganic fertilizer (urea) amendment on crude oil degradation and uptake by water hyacinth (Eichhornia crasssipes). Experimental units (fresh borehole water) were spiked with crude oil at four different concentrations and then were randomly assigned fertilizer (urea) at three different concentrations. Crude oil degradation and absorption were determined monthly by measuring total petroleum hydrocarbon (TPH) in water column and water hyacinth, respectively. The water hyacinth planted in the control absorbed significantly (p < 0.05) higher TPH than the treatments amended at 6 mg/l and 10 mg/l urea. The rate of absorption of TPH by water hyacinth was highest in treatments amended at 10 mg/l urea except in the experimental unit spiked at 60 mg/l crude oil. The results of this study showed that water hyacinth absorbs petroleum hydrocarbon and thus can be used in phytoremediation of crude oil-polluted aquatic ecosystem.
Structural-scaling transitions in mesodefect ensembles as mechanisms of relaxation and failure in shocked and dynamically loaded materials (experimental and theoretical study)

Nonlinear aspects of relaxation and failure are related to new type of critical phenomena in ensembles of mesoscopic defects - structural-scaling transitions, generation of specific collective modes of mesodefects, which subject the relaxation and kinetics of damage-failure transition. Theoretical results were supported by original experiments and allowed us to propose the explanation: the transition from the steady-state to the branching and stochastic regimes of crack dynamics, fragmentation scenario, the steady-state structure and the four power law universality of the plastic wave front, the "failure wave" phenomenon as delayed failure effect related to the excitation and propagation of mesodefects collective mode with "blow-up" damage localization kinetics.
Polyelectrolyte-modified layered double hydroxide nanocontainers as vehicles for combined inhibitors

In this work, nanocontainers based on layered double hydroxide (LDH) loaded with two different corrosion inhibitors, namely 2-mercaptobenzothiazole (MBT) and cerium(III) nitrate, were prepared. MBT was intercalated into LDH galleries in anionic form by anion-exchange, while Ce3+ was fixed between polyelectrolyte layers on the surface of LDH-MBT nanoplatelets by the Layer-by-Layer (LbL) method. Both inhibitors were found in the modified LDHs (LDH-Mod) by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy. The release studies performed by UV-vis spectrophotometry indicated that the main triggering conditions for release of MBT from LDHs changed when LDH nanoplatelets were covered with polyelectrolytes. Furthermore, electrochemical impedance spectroscopy and DC polarization were used to investigate the effect in combining MBT− and Ce3+ within the same nanocontainer, for the corrosion protection of 2024-T3 aluminium alloy directly in solution as well as in a hybrid sol–gel coating. The obtained results open prospects for application of these systems as additives in multifunctional smart coatings.
CORRELATION OF LIQUID-SIDE MASS TRANSFER COEFFICIENT FOR SINGLE PARTICLES AND FIXED BEDS

The mass transfer coefficients between particles and liquid were correlated for single particles and for fixed beds with specific power group including the energy dissipation rate defined for a particle. The following empirical equations were obtained over a wide range from laminar to turbulent flow, assembling the published data including those of the authors for fixed beds: for single particles where e is energy dissipation rate per unit mass of liquid flowing around a particle, Dpis particle diameter, and v is kinematic viscosity of liquid. These equations, almost identical, are also practically the same as published ones for stirred tanks, suspended bubble columns, and two-phase tube-flow. The agreement suggests that specific power group maybe useful as a general parameter in the study of mass-transfer phenomena between liquid and particles where the liquid is either quiescent or turbulent and the particles are either fixed or suspended.
A Versatile Polymer Co‐Network with Broadened Glass Transition Showing Adjustable Multiple‐Shape Memory Effect

In this study, a versatile poly(methyl methacrylate)–poly(ϵ-caprolactone) covalently crosslinked polymer co-network (PMMA–PCL CPN) tethering all polymeric chains between netpoints is designed and prepared to develop a novel type of adjustable multiple-shape memory polymers. The CPN is demonstrated to produce a broadening of glass transition and memorize up to four different shapes based on a single thermal transition for the first time, as the whole energy stored in the broad transition can be distributed into several parts for multi-step shape fixation and recovery in one-shape memory cycle. Furthermore, the versatile multiple-shape memory effects from dual to quadruple can be adjusted simply by shifting the corresponding deformation temperatures on demands, without variation of material chemistry.
A molecular dynamics study of the pentacyclo-undecane (PCU) cage polypeptides of the type Ac-3Ala-Cage-3Ala-NHMe

An extensive exploration of the conformational space of the seven-residue peptide sequences, Ac-Ala-Ala-Ala-Cage-Ala-Ala-Ala-NHMe and the model peptide Ac-Ala-Ala-Ala-Ala-Ala-Ala-Ala-NHMe, was carried out using single trajectories of molecular dynamics (MD) in the solution phase using the periodic boundary conditions. Our MD studies revealed that the majority of the motifs of the PCU cage peptide exist as type I–III β-turns along with their mirror conformations, viz. type I′–III′ β-turns. This peptide sequence adopted a U-shaped backbone, with alpha-helical characteristics. The results reported here provide further evidence that the PCU cage amino acid exhibits C7eq, C7aq, αR and αL conformations in aqueous solution.
Effect of various pulp properties on the solubility of cellulose in sodium hydroxide solutions

Abstract The dissolution of pulps with varying characteristic properties, for example cellulose chain length or content of hemicellulose, has been investigated in two alkaline solvent systems [sodium hydroxide (NaOH)/urea/thiourea (8:8:6.5 by wt.) and NaOH/zince oxide (ZnO) (9:0.5 by wt.)]. One standard paper pulp, two dissolving pulps and three pretreated pulps were selected for this study. The dissolution parameters in focus were the fiber dimensions, average degree of polymerization (DP), polydispersity, water retention value and content of hemicelluloses. The solubility was not influenced by the fiber dimensions. The only significant properties, according to variable importance plot, were DP and composition of the hemicelluloses. It was also established that mass transfer effects during the dissolution stage plays an important role in the dissolution of cellulose derived from pulp fibers.
Thermodynamic and Kinetic Characterization of Porous Graphitic Carbon in Reversed‐Phase Liquid Chromatography

Abstract The thermodynamics and kinetics of solute transfer on porous graphitic carbon (PGC) are studied for two series of aromatic hydrocarbons, alkylbenzenes and methylbenzenes. The retention behavior is characterized as a function of temperature, pressure, length of alkyl chain, and number and position of methyl substituents. In the thermodynamic studies, the retention factor (k) increases with an increase in the length of alkyl chain or number of methyl substituents. The data indicate that increases in the number of methylene and methyl substituents result in more negative changes in molar enthalpy (ΔHsm). Hence, the transition from mobile to stationary phase is a more energetically favorable, exothermic process with each methylene or methyl group added. The data also show that the change in molar volume (ΔVsm) is close to zero, which is consistent with an adsorption mechanism on PGC. Enthalpy‐entropy compensation is observed for both homologous series, and the compensation temperature suggests that the retention mechanism is distinctly different for the methylene and methyl groups. In the kinetic studies, the rate of solute transfer increases with an increasing number of methylene and methyl groups. The activation enthalpy from the stationary phase to transition state (ΔH‡s) is found to increase with an increasing number of methylene and methyl groups. But the activation enthalpy from the mobile phase to transition state (ΔH‡m) is much smaller than ΔH‡s and, at the same time, is very similar for all the solutes. The activation volumes (ΔV‡s and ΔV‡m) are very close to zero, again owing to the adsorption mechanism on PGC. These results demonstrate that the retention mechanism for PGC, which is based on adsorption, is different from that for octadecylsilica, the most widely used stationary phase in liquid chromatography.
A Novel Method for the Improved Skin Whitening Effect Based on Nanostructured Lipid Carrier

The nanostructured lipid carrier (NLC) encapsulating two potent skin whitening ingredients was developed by our group for cosmetic and dermatological treatment. The particle showed spherical shape morphology under atomic force microscope, and the value of the zeta potential of the NLC was − 65.4 ± 4.3 mV. Good physical stability was observed by dynamic light scattering during 45 days’ storage, respectively. The skin whitening effect was improved when applying the NLC. Therefore, the NLC might be a potential delivery vehicle in dermal products.
Liquefaction of Cellulose in the Presence of Phenol and Main Reaction Pathway of its Liquefied Products

The liquefaction of cellulose in the presence of phenol without or with sulfuric acid as catalyst was investigated. The liquefied products were characterized by GC/MS and FTIR. Results showed that reaction temperature and reaction time had obvious effects on liquefaction of cellulose. Sulfuric acid showed an excellent catalytic degradation. The chemical compositions of the liquefied products produced using sulfuric acid catalyst or not were almost identical, and the majority of the identified liquefied products were methylene bisphenol and its isomers. During the process of liquefaction, the degradation of cellulose and condensation polymerization occurred at the same time. The last liquefied products were greatly dependent on the reaction conditions.
Copper stress affects grain filling in rice

Abstract Rice (Oryza sattva L.) cv. Jaya was grown in refined sand at graded levels of copper (Cu) viz. 0.00065, 0.0065, 0.013, 0.065, 0.13, 0.65, and 6.5 mg L‐1. In acute Cu deficiency (0.0065, 0.00065 mg L‐1), the visible foliar symptoms appeared on young leaves as chlorosis changing to necrosis, later affected leaves appeared papery and withered. The biomass and grain yield were highest at 0.065 mg L‐1 and compared to this, the decrease in both parameters was significant at low and high Cu supply. The concentration of Cu in grains increased from 0.4 in acute deficiency to 47.4 ppm at excess Cu. In rice leaves, concentration of sugars and activities of polyphenol oxidase and ascorbic acid oxidase were decreased both by low and excess Cu. Both low and high Cu also retarded the grain formation as well as their quality by decreasing the grain yield and the concentration of starch, sugars and proteins in grains and activities of amylase, invertase and starch phosphorylase at the time of grain filling in see.
AN INDIRECT LASER-INDUCED TEMPERATURE JUMP DETERMINATION OF THE SURFACE PKA OF 11-MERCAPTOUNDECANOIC ACID MONOLAYERS SELF-ASSEMBLED ON GOLD

The indirect laser-induced temperature jump (ILIT) method is used to determine the acidity (pKa) of monolayers composed of 11-mercaptoundecanoic acid (MUA) self-assembled on vapor-deposited gold film electrodes in contact with either 0.10 or 1.0 M ionic strength NaClO4 electrolyte solutions. The ILIT technique may be used to measure the pKa of a surface-attached acid because the magnitude of the ILIT response is related to the potential gradient at the electrode/electrolyte interface which is, in turn, related to the extent of ionization of the acid. The relevant data are the potentials of zero ILIT response versus pH. A simple two-layer model of the acid-modified electrode/electrolyte interface and Gouy−Chapman double layer theory (modified for the onset of dielectric saturation effected by the large concentration of charge present at this interface when a substantial fraction of the carboxylic acid moieties are ionized) were employed to analyze these data. This analysis gives pKa = 5.7 ± 0.2 at 0.10 M i.
Population dynamics and metabolic alternations of AOB in activated sludge under Cu shock loads

The ammonia consumption, respiration rates (sOURNH4), expression of functional genes (amoA and hao) and community structures of ammonia-oxidizing bacteria (AOB) under copper (Cu) shock loads were simultaneously studied. The results showed that respiratory activities and gene transcriptional responses were sensitive to Cu toxicity. Cu inhibition and nitrite accumulation stimulation coeffected the expression of amoA. A Cu loading concentration at the ppm (mg L–1) level produced an irreversible inhibition of the expression of hao. The self-repair ability of amoA was stronger than that of hao under Cu shock loadings. A principal component regression analysis model revealed that soluble Cu and intracellular Cu played important roles in the inhibitory actions of Cu shock loading on AOB. Furthermore, the linear model (R2 = 0.92) adequately fitted the inhibition of soluble Cu to sOURNH4 while the inhibition actions of the intracellular Cu on AOB respiration conformed to a biological receptor model (I%inhibition = 100/(1 + Ki/[M]), Ki = 7.4). An uncultured Nitrosospira sp. exhibited stronger tolerance to Cu toxicity than Nitrosomonas sp. in this study. The results and their understanding lead to a deep comprehension of Cu inhibitory mechanisms on AOB in complex activated sludge systems.
Modeling of the Soluble Microbial Products (SMP) in Anaerobic Membrane BioReactors (AMBR): Equilibria and stability of the AM2b model

Abstract This paper deals with the modification of the AM2 model (Bernard et al. (2001)) to integrate the production and the degradation of the Soluble Microbial Products (SMP) in an Anaerobic Membrane BioReactor (AMBR). The developed model takes into account the characteristics of membrane bioreactors, namely i) there is no biomass in the effluent, ii) part of the SMP, corresponding to the biggest molecules, is retained in the reactional medium, iii) the decay rate and the withdraw of the biomass are considered. Possible equilibria of the system are calculated, and the influence of the maximum growth rate of the biomass on the SMP on these equilibria is analyzed. It is shown that the presence of this new variable in the model changes the qualitative properties of the classical AM2 model.