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This work aims to study the structural and elastic properties of tetragonal lead dioxide (β-PbO2) material using first-principles calculations. Features such as lattice parameters, bulk modulus and its first pressure derivative, elastic constants, mechanical parameters, sound velocities, Debye temperature and melting temperature have been investigated, and their dependence on pressure in the range 0–1 GPa has been analyzed and discussed. Upon compression, the stiffness of the material of interest is found to become larger as compared to that at zero pressure. Moreover, its tetragonal structure fulfills the mechanical stability criteria in all studied pressure range. Besides, the analysis of Pugh’s ratio shows that PbO2 behaves in a ductile manner.

We report a theoretical investigation on the finite temperature thermophysical properties of tetragonal lead dioxide (β-PbO2) material using ab initio calculations in the framework of the density functional theory within the generalized gradient approximation. The thermophysical properties for temperatures up to 600 K are determined and analyzed in detail using the quasi-harmonic Debye model. Experimentally, the β-PbO2 transforms to α-PbO2 at around 1 GPa. For that, the maximum value of pressure considered here is taken to be 1 GPa. Our findings show that the thermophysical properties of interest vary monotonically with both temperature and pressure which is consistent with previous studies of semiconducting materials. At zero pressure and temperature of 300 K, the isothermal bulk modulus and the Debye temperature are found to be around 113 GPa and 370.5 K, respectively.

The study aimed to evaluate the interaction between dietary crude protein (CP) and condensed tannins (CT) on the growth performance, carcass composition and meat quality of ram lambs. Twenty-four White Alpine lambs were fed a basal diet consisting of 56% birdsfoot trefoil (BT) silage and 44% hay (67.1% grasses, 4.3% legumes and 28.6% herbs). In addition, lambs were offered either a barley concentrate to reach the predicted protein requirements (BP) or a barley and soybean meal concentrate to extend the CP level 20% above the requirements (HP). The diets were either untreated (BP−; HP−) or treated (BP+; HP+) with the CT-binding polyethylene glycol (PEG). Lambs fed HP− and HP+ diets had greater (P

The beneficial effects of polyphenol intake such as improved nitrogen retention make them interesting feed supplements for ruminants. In contrast, dietary polyphenols may have adverse effects on the bioavailability of nutrients and palatability of the feed which might impair growth performance. The beneficial and adverse effects might differ between different ruminant species as well as between direct intake and intake of polyphenol metabolites via suckling when supplemented to lactating dams. This study investigated the effects of maternal and direct polyphenol supplementation via grape seed extract in sheep and goats on growth, slaughter performance, meat quality and fatty acid profile. The diet of lactating East Friesian Dairy sheep (n = 11) and Saanen goats (n = 9) and of their lambs (n = 16) and kids (n = 13), respectively, was supplemented either with grape seed extract (dams: 7.4% and offspring: 5.6%, P) or without (C). This resulted in four groups per species, namely maternalC/offspringC, maternalC/offspringP, maternalP/offspringC, and maternalP/offspringP. In lambs but not in goats, maternalP increased average daily gain and improved slaughter performance whereas offspringP had no effect. Maternal and offspring diet did not affect physicochemical meat quality in lambs, but direct intake of grape seed extract increased rancid aroma of burger patties. In goat kids, both maternal and offspring diets slightly affected meat colour. While groups of meat fatty acids (FAs) were not affected by diet in both species, maternalP in lambs as well as maternalP and offspringP in goat kids increased the meat n–6 to n–3 FA ratio compared to the respective control groups. In goat kid but not in lamb meat, direct intake of polyphenols affected the proportions of several rumen biohydrogenation intermediates. In conclusion, grape seed extract can be applied in both the maternal and offspring diets in sheep and goats while maintaining or even improving offspring growth performance and carcass quality. Only few species-specific effects of grape seed extract supplementation were observed, and additive effects were scarce. Larger studies are required to confirm the observed species-specific growth response to maternalP during lactation. The underlying reasons for this differential response need to be further evaluated., Animal, 15 (9), ISSN:1751-7311, ISSN:1751-732X

The aim of the present work is the study of the performances of dry cells containing the electrolytic MnO2, natural MnO2, or a mixture of both. The two components have been characterized by chemical analysis. The continuous discharge tests done on the dry cells based on EMD present a discharge time largely greater than that of the pure NMD; however, the cells containing a mixture present intermediate values of the discharge time. The value of the diffusion coefficient estimated by the GITT or impedance spectroscopy shows that the H+ diffuses more quickly in the EMD variety that in the NMD one.

In the present study, the effects of feeding 450 g/day of rumen-protected fish oil (FO) compared to sunflower oil (SO) to Angus heifers (60 g/kg total intake) were quantified. Animal performance was not affected whereas the physico-chemical meat quality, assessed in three muscles, was slightly affected by diet. The oxidative shelf life of the perirenal fat declined with FO compared to SO. Despite the formerly shown increased n–3 fatty acid proportions of meat due to FO supplementation, a trained sensory panel identified an only slightly more intense fishy flavour in grilled steaks and beef patties from the FO compared to the SO group. In FO compared to SO patties, flavour intensity was more pronounced. The perception of off-flavours was negligible and differences between muscles were larger than between diets. In conclusion, supplementing ruminants with FO containing nutritionally beneficial n–3 fatty acids results in few side-effects on meat quality, restricted to quite faint off-flavours and a shorter fat shelf life.

We prepared MnO2 by electrolysis of manganese sulfate solution recovered from used batteries and commercial manganese sulfate solution. The comparative study of the two samples using electrochemical techniques in alkaline solution shows that the two samples exhibit the same behavior. From XRD, we identified and indexed both samples by γMnO2 orthorhombic structure. We estimated the proton diffusion coefficient using galvanostatic intermittent titration technique (GITT). Our calculated data are in good agreement with theoretical values for both samples. In addition TG analysis shows the same thermal profile for both samples.

The resulted material after a discharge of Zn-MnO2 cell is a mixture of various oxide and hydroxide. The recycling of spent batteries cathodic materials from them is of great scientific and economic interest. In this work, the MnO2 was recycled by chemical methods, the MnO2 was oxidized using hydrogen peroxide (H2O2) at neutral pH, the obtained materials were characterized by different methods including cyclic voltammetry, impedance spectroscopy, atomic absorption spectroscopy and X-ray diffraction. The preliminary results demonstrated that by chemical oxidation with hydrogen peroxide (H2O2 ) is a suitable method for recuperation of a pure MnO2 and it could be used in a plant for recycling batteries.

This work aims to improve the performance of solar cells with structure SnO2/CdS/CIGS/Mo by using the solar cell capacitance simulator (SCAPS-1D). Our idea is to insert the SnS layer between the absorber layer CIGS and the Mo (molybdenum) back contact. A maximum conversion efficiency of 24.45% (VOC = 0.78 V, JSC = 38.66 mA/cm2, FF = 0.80) was achieved with 1 μm-CIGS absorber layer, 50 nm-CdS buffer layer, 200 nm of ZnO window layer and 300 nm of SnS BSF layer. This study shows that ultra-thin CIGS solar cells with a BSF layer give better results compared to the work of Gloeckler (2005), which presented an efficiency of 19.62% (VOC = 0.61 V, JSC = 39.23 mA/cm2, FF = 0.81) with 3 µm thickness of CIGS in the structure ZnO/CdS/CIGS/Mo. In addition to this, the cells’ stability with temperature was studied and analysed.

International audience; Today toxic phenolic compounds are a major source of pollution and are mainly the result of various industrial wastes such as plastics, polymers, insecticides, etc. In this context, the originality of our study is a first as we used a new composite material assembled by mixing activated carbon (AC), organo activated bentonite (OAB), and alginate (A). The prepared adsorbent materials were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and point of zero charge (pH(PZC)). The influence of various factors such as contact time, pH, adsorbate concentration, and temperature on the adsorption of bisphenol A (BPA) and 2,4,5-trichlorophenol (TCP) has been investigated. The equilibrium data were fitted well by Freundlich isothermal model and the maximum adsorptions of BPA and TCP onto alginate/organo activated bentonite/activated carbon beads (A-OAB-AC), were 368.2 and 385.1 mg.g(-1), respectively. The adsorption of BPA and TCP was observed to follow pseudo-second order mechanism as well as the thermodynamic parameters confirm also endothermic spontaneous and physiosorption processes. In addition, the resulting adsorbent reusability was demonstrated by at least six cycles, indicating that the A-OAB-AC can be used as a promising adsorbent for removal of toxic pollutants from aqueous solutions.

In this study, acid-activated organobentonite (OAB), calcium alginate (A) and calcium alginate/acid-activated organobentonite composite beads (A-OAB) were prepared and applied for the removal of methylene blue from solutions in batch system. The zero point charge of pH (pHpzc), Scanning electron microscopy (SEM) and Fourier transformed infrared spectroscopy (FTIR) analysis were carried out. The effects of pH solution (2-11), temperature (15, 25, 35 and 45°C), initial concentration (20-500mg/L), and contact time were investigated. The adsorption processes fitted well with the pseudo-second-order kinetic model and both models Langmuir and Chapman isotherms. Results showed that the maximum adsorption capacities of (OAB), (A) and (A-OAB) for the adsorption of MB were 263.80, 483.6 and 799.43mg/g at 25°C, respectively. Thermodynamic studies showed spontaneous and endothermic nature of the overall adsorption process. Desorption tests showed that the removal efficiency of MB decreased from 95 to 89.7% after six regeneration cycles for (A-OAB). From this, (A-OAB) can be utilized as an economical adsorbent for the removal of basic dyes from the contaminated waste water.

We studied the blend formed by electrochemical polymerization of bithiophene monomer (BTh) on electrolytic manganese dioxide (γ-MnO 2 ). The composite material (PBTh/γ-MnO 2 ) has been synthesised in 0.01 M PBTh/0.1 M LiClO 4 /CH 3 CN by chronoamperometry test at oxidation potential 1.1 V vs. saturated calomel electrode during 20 min, and then characterized by different methods including cyclic voltammetry, impedance spectroscopy, FTIR spectroscopy, and magnetic measurements. These blends have been tested as positive electrode in Zn//γ-MnO 2 cells. Good discharge performance was obtained with the modified MnO 2 , which exhibits better active material; increasing cell capacity is observed.

The proton diffusion coefficient for both fresh and heat-treated (140 and 230 °C, respectively) α and β-PbO 2 electrodes was estimated at room temperature using Galvanostatic Intermittent Titration Technique (GITT). PbO 2 samples were prepared by electroformation of cured plates. HSbO 3 · x H 2 O with a conductivity of 3.29 × 10 −3 Ω −1 cm −1 , was used as solid protonic conductor (SPC) electrolyte. It was found that when structural water is removed, the capacity of both α and β-PbO 2 electrodes decreases and the ohmic drop increases. The departure of structural water affects considerably the value of proton diffusion coefficient.

The present work revealed that the chemical polymerization of ortho-ethoxyaniline yields two types of polymers not only with different spectroscopic properties but also with different molecular weights: (1) a green form, which corresponds to the high molecular weight fraction of the polymer with a molecular weight of 800,000 g mol−1 based on the polystyrene calibration. It is mainly composed of quinoid and benzoid structures, which is an indication of a half-oxidized polymer (emeraldine). This form of the polymer is insoluble in water-miscible solvents like ethanol and methanol and thus cannot be tested in terms of corrosion inhibition efficiency; (2) a red form, which corresponds to the low molecular weight fraction of the polymer with a molecular weight of 44,000 g mol−1. It is composed mostly of quinoid structures and exhibits an oxidation state similar to that of the completely oxidized polymer (pernigraniline). In our case, the polymer fraction, which is soluble in alcohol, was first tested as a corrosion inhibitor for mild steel in acidic media, not only at conventional molecular weight (44,000 g mol−1) but also at different molecular weights. These different molecular weights of the polymer were obtained by adding varying amounts of neutral salt to the synthesis environment. Next, the effect of the molecular weight of the red form of the polymer on the corrosion inhibition efficiency of mild steel in hydrochloric acid solutions was investigated. The obtained results showed that the adsorption of the polymer alcoholic form obeys a Temkin adsorption isotherm with no significant change as function of inhibition efficiencies for a series of molecular weights ranging from13,000 to 124,000 g mol−1. The effect of temperature on the corrosion behavior of mild steel in 1M HCl with addition of 100 ppm of the alcoholic form of poly(ortho-ethoxyaniline) was studied in the temperature range 25–60°C. The associated activation corrosion energy was determined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1275–1284, 2004

The mechanism of the reduction of α- and β-PbO 2 electrodes has been studied using an all-solid-state system. PbO 2 samples were prepared by electroformation of cured plates. HSbO 3 · x H 2 O was used as the solid electrolyte. Galvanostatic discharge and Coulometric measurements were carried out at room temperature. The capacity was determined by integration of I – t curves and the number of electrons was calculated using Faraday’s law. The electrochemical reduction of both α- and β-PbO 2 proceeds in two stages. The results show that the electrochemical reduction of both α- and β-PbO 2 takes place in the gel zones according to a proton–electron mechanism.

The influence of ‘hydrogen loss’ on the electrochemical properties of both ;-PbO2 and ;-PbO2 was studied using galvanostatic discharge and cyclic voltammetry. The thermal decomposition of electroformed PbO2 shows two types of hydration water: the first type, which disappears at low temperature, is adsorbed on the surfaces of the PbO2 particles, and the second one is localized within the PbO2 crystal structure. The reduction process of PbO2 in lead/acid cells is mainly determined by diffusion processes within the oxide. The hydrogen diffusion coefficient tH in lead dioxide has been determined at 25 °C; the values obtained are between 0.42 and 1.67 × 107 cm2 s1. The remo. The removing of ‘structurally bonded’ water, by heating the samples at 230 °C, affects considerably the electrochemical properties of PbO2 and leads to a decrease in tH..

The aim of this paper is to propound a novel conception of a comparison electrode, allowing the evaluation of both anode and cathode polarizations involved in the all-solid Zn PbO 2 cell. This consists of separating each electrode layer deposited on the electrolyte pellet into two distinct parts. During discharge, one of these parts, which will be crossed by the current, acts as a working electorde while the other, staying at its equilibrium state, can play the role of a comparison electrode. First, the reversibility and the potential stability of the comparison electrode are checked. Subsequently, the method is applied to demonstrate the effect of electrode morphology and current density of discharge on electrode polarization in the Zn PbO 2 system.

The cathodic behaviour of α- and β-PbO 2 was studied in the presence of lithium ions using slow-scan voltametry. The β-PbO 2 shows two peaks at 2.95 V and 2.45 V versus Li/Li + . However, in the case of α-PbO 2 , similar peaks appear at 2.74 V and 2.35 V versus Li/Li + . The values of D Li + calculated for both samples were 5 × 10 −13 cm 2 s −1 for α-PbO 2 and 10 −14 cm 2 s −1 for β-PbO 2 . The α phase seems to be a better lithium conductor than the β phase.

It is well known that lead dioxide contains, what has been called, ‘structural water’. Present in the form of OH− ions replacing O2− ions in the anionic sublattice, the ‘structurally bonded’ water can be removed by heating, in the temperature range from 150 to 250 °C. In the present study, the discharge capacities of fresh and heat-treated (140 and 230 °C, respectively) α- and β-PbO2 samples were evaluated in H2SO4 solution of 1.28 g cm−3 sp. gr. at different current densities of 5 to 40 mA cm−2. It was found that the capacity decreased when structural water was removed. This loss of capacity is important when α-PbO2 samples are considered. The energy of dehydroxilation was deduced by applying kinetic considerations to thermograms, obtained experimentally. The removal of the OH− groups from β-PbO2 needs an energy twice that of the α-form.

The influence of the initial amount of H2SO4 added to lead powder on the phase compositions of plates in the curred and formed states has been studied. IR spectra, X-ray diffraction, scanning electron microscope observations, and wet-chemical analysis are used as techniques of investigation. It was found that the phase composition of the paste depends on the H2SO4:oxidized lead powder ratio. In addition, it is found that α- and β-PbO2 are formed in the lead/acid battery positive from 3PbO·PbSO4·H2O. the amounts of these two compounds were strongly affected when varying the quantity of H2SO4 with respect to the lead powder.

The cathodic behaviour of both varieties a - and β-PbO 2 in the presence of lithium ion was studied. The chemical lithiation was obtained by reaction with n-butyllithium. The chromatographic analysis of the chemical products revealed both octane and butane. The presence of butane as coproduct could be due to the hydrogen substitution reaction with n-butyllithium. The electrochemical behaviour was studied with deposited PbO 2 cathodes on stainless steel with a LiClO 4 /polyethylene oxide electrolyte. By using slow scan voltammetry, the cathodic reduction process results in the peak reduction at potential 2.4 V versus Li/ Li + for α-PbO 2 and 2.74 V versus Li/Li + for β-PbO 2 . The present work suggests that cathodic reduction is lithium intercalation in surface-layered PbO 2 molecules.

The thermal degradation of α and β PbO 2 and its relationship to capacity loss was studied using galvanostatic discharge and voltamperometry. The results clearly demonstrate the dramatic effect of the thermal treatment on the capacity of the PAM. The variation of proton diffusion with temperature was determined for both α- and β-PbO 2 . The two forms of PbO 2 exhibit different behaviour with regard to water loss.