An analysis of farmers?? use of phosphorus fertiliser in industrial agriculture: a case study in the Bordeaux region (south-western France)

Global phosphorus (P) reserves are rapidly being depleted and agriculture is a major contributor to P consumption worldwide. Moreover, agricultural P use may lead to local excess of P in soils, resulting in water eutrophication. To remedy this situation, it is necessary to understand the key factors underlying P use by farmers within such a context. The objective of this article is to understand how farmers use P fertilisers under agricultural conditions. Particular attention was paid to the use of conventional decision-making tools such as soil analysis by farmers. Industrial agriculture, characterised by high levels of specialisation, input use and production yields, was considered as a case study. Forty farmers involved in industrial agriculture in south-western France were interviewed in 2008 about their P use. Soil analyses were collected when available. Input/output P balances were computed at the plot scale. Moreover, records of farmers?? fertilisation practices were analysed from a database developed by a technical advisory group. Results showed that 90% of farmers had a crop-specific and yearly P fertilisation strategy. This yielded very positive P balances for vegetable crops. Few farmers used recommendations based on soil analyses: in most cases, the amounts of P used by the farmers were lower than those recommended. When asked for their opinion about the role of P in agriculture, most farmers explained that P fertilisation helped boost the growth of spring crops in the event of adverse weather conditions. This revealed the emphasis placed on ??plant-based?? strategies for P management, as opposed to ??soil-based?? strategies, thus reinforcing annual fertilisation strategy. This study provides a foundation for understanding key factors underlying P consumption in agriculture.     

A combined canonical variate analysis and Fisher discriminant analysis (CVA–FDA) approach for fault diagnosis

This paper proposes a combined canonical variate analysis (CVA) and Fisher discriminant analysis (FDA) scheme (denoted as CVA–FDA) for fault diagnosis, which employs CVA for pretreating the data and subsequently utilizes FDA for fault classification. In addition to the improved handling of serial correlations in the data, the utilization of CVA in the first step provides similar or reduced dimensionality of the pretreated datasets compared with the original datasets, as well as decreased degree of overlap. The effectiveness of the proposed approach is demonstrated on the Tennessee Eastman process. The simulation results demonstrate that (i) CVA–FDA provides better and more consistent fault diagnosis than FDA, especially for data rich in dynamic behavior; and (ii) CVA–FDA outperforms dynamic FDA in both discriminatory power and computational time.     

Oxidative degradation of poly (vinyl acetate) and poly (ε-caprolactone) and their mixtures in solution

The oxidative degradation of the poly (ε-caprolactone) (PCL), poly (vinyl acetate) (PVAC) and their mixtures in dichlorobenzene has been investigated at various temperatures (70-130°C) in the presence of benzoyl peroxide. The interaction between the polymers is quantified by monitoring the molecular weights of individual polymers using gel-permeation chromatography. The various physical mixtures employed in the present investigation are , and wt%/wt% PCL/PVAC. Experimental data indicated that the degradation is random without cross-linking and repolymerization. An optimum in degradation temperature (corresponding to maximum degradation rate) of 105°C was observed for the entire range of polymer compositions (0-100% PCL) investigated. This optimum temperature of degradation is characteristic mostly of the initiator and only to a small extent of the degrading polymer system. The experimental results of the mixtures indicated that the degradation rates of PVAC are significantly enhanced, while the degradation rates of PCL are decreased in the physical mixture. This can be attributed to the proton-accepting and proton-donating nature of PCL and PVAC, respectively. A radical mechanism for the oxidative degradation of pure polymers and their mixtures has been proposed and a model based on continuous distribution kinetics was developed considering the interaction of the polymers through hydrogen abstraction and the parameters were evaluated numerically. The activation energies for the peroxide attack for the PCL and PVAC are 10.5 and , respectively. The activation energies for the random chain scission of PCL and PVAC are 10.6 and , respectively.     

Dynamic quenching of 5-(2′-ethyl-hexyloxy)-p-phenylene vinylene (MEH-PPV) by charge transfer to a C60 derivative in solution

The fluorescence of 5-(2′-ethyl-hexyloxy)-p-phenylene vinylene (MEH-PPV) quenched in solution in 1,2-dichlorobenzene by a soluble derivative of C₆₀ [1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C₆₁; [6,6]PCBM] is studied by changing the concentration of the quencher and by varying the temperature. For MEH-PPV and PCBM dissolved in 1,2-dichlorobenzene, the Stern–Volmer constant (K_SV) is 2 × 10³M⁻¹. At high temperature, K_SV is enhanced because thermal energy facilitates the diffusion of PCBM. The results show that dynamic quenching (rather than static quenching) is the basic mechanism. Comparison with data obtained from quenching studies of trans-stilbene indicates that a single acceptor in contact with an MEH-PPV macromolecule quenches the luminescence from hundreds of repeat units. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2553–2557, 2001     

ω-Iodinated poly(dimethylsiloxane) as a chain transfer agent in iodine transfer radical polymerization of vinyl acetate and dibutyl maleate: synthesis and structural characterization

Iodine transfer radical homo- (ITP) and copolymerization (ITCP) of vinyl acetate (VAc) with dibutyl maleate (DBM) initiated by 2,2?-azobis(isobutyronitrile) (AIBN) were performed in bulk at 80 °C in the presence of ω-iodo- terminated poly(dimethylsiloxane) (PDMS-I) as a macro-chain transfer agent (macro-CTA). ¹H-NMR and gel permeation chromatography (GPC) results confirmed formation of the PDMS-b-PVAc diblock copolymer. Moreover, the results of ¹H-NMR showed that the iodo-terminated chain ends are unstable and decompose to the aldehyde moieties. On the other hand, different behaviour was observed in the ITCP of the VAc and DBM. ¹H-NMR and GPC results showed that presence of DBM in the reaction medium leads to degradation of the C-I bond of the PDMS-I, resulting in the generation of HI. In fact, PDMS-I acts as in situ generator of the CTA in the presence of DBM via reaction between the generated HI and VAc. In other words, it was found that P(VAc-co-DBM) copolymer chains are synthesised by ITP mechanism in the presence of in situ generated 1-iodoethyl acetate as a CTA. Therefore, a mixture of PDMS and P(VAc-co-DBM) chains was obtained.     

Heat and mass transfer coefficients of liquid desiccant dehumidification/regeneration processes with non-thermal equilibrium(Ⅰ) Model and Le-hD evaluation method

溶液除湿装置是溶液除湿空调系统中一个重要单元,其内部传热传质规律对系统性能起到决定性影响。在溶液绝热除湿模型基础上,提出考虑热不平衡的除湿模型用以计算溶液除湿过程的传热传质系数。模拟计算发现考虑热不平衡模型计算的溶液和空气出口参数与实验值能更好吻合,从而说明该模型能更准确计算除湿过程传热传质系数。当热容率比C^*≥1.0时,考虑热不平衡除湿模型计算的传质单元数和Lewis数要远优于绝热模型计算结果;而当C^*≤0.05时,考虑热不平衡除湿模型和绝热模型计算结果相差较小。     

A novel green inhibitor for C-steel corrosion in 2.0 mol·L~(-1) hydrochloric acid solution

The corrosion inhibition characteristics of aqueous extract of seeds of Melia azedarach L.(MA) have been studied as eco-friendly green inhibitor for corrosion control of C-steel in 2 mol·L~(-1) HCl solution by gravimetric and electrochemical methods. The results depict that, the extract inhibits efficiently the corrosion of carbon steel in hydrochloric acid. The efficiency of extract is increased with increasing the extract concentration but independent on the studied temperature. The adsorption of the extract components onto the steel surface was found to be spontaneous, and follows Langmuir adsorption isotherm. The surface morphology of C-steel, in the absence and presence of MA extract in 2.0 mol·L~(-1) hydrochloric acid solution, was studied using scanning electron microscopy(SEM).     

Highly efficient near-infrared (NIR) luminescent tris-β-diketonate Yb3 + complex in solution and in PMMA

In the series of binary tris-β-diketonate complexes [Ln(L)₃(Phen)] (HL = (Z)-3-methyl-1-phenyl-4-(2,2,2-trifluoro-1-hydroxyethylidene)-1H-pyrazol-5(4H)-one; Phen = 1,10-phenanthroline; Ln = La, 1; Ln = Nd, 2; Ln = Yb, 3; Ln = Er, 4 or Ln = Gd, 5), the relatively lower ligands-based ³ππ^⁎ energy level (18,727 cm^− 1) results in the highly efficient NIR luminescence (Ф_Yb^Yb = 1.37% and Ф_Yb^L = 1.06%) of Yb^3 +-based 3 in solution and the higher NIR quantum yield (Ф_Yb^Yb = 1.77% and Ф_Yb^L = 1.31%) in PMMA (Poly(methyl methacrylate) besides the improved physical properties.     

Experimental electrohydrodynamics of poly(γ-Benzyl-L-Glutamate) in M-Cresol solution subjected to shear flow and electric fields

Electrohydrodynamics of a dilute solution of rigid macromolecules was experimentally studied in a continuation of previous theoretical work. We used poly(γ-benzyl-L-glutamate), having 4 different molecular weights ranging from 15,000 to 236,000, dissolved in m-cresol. Poly(γ-benzyl-L-glutamate) solutions were subjected to combinations of simple shear flow field and uniform electric field perpendicular to the shear direction. Transient birefringence and extinction angle were simultaneously measured using the phase-modulated birefringence method. Steady state results were compared with the theoretical prediction from previous works and rotational difiusivity and permanent dipole strength of PBLG were obtained from multiple parameter fitting. Consequently, the optical state of PBLG solution could be explained to a certain extent by the dimensionless field parameters established in the previous theory.     

Electro-catalytic characterization and dye degradation of Ti1−x(Bi)xO2 in acidic solution

The authors in this study used the sol–gel process to prepare Bi-doped TiO₂ as a novel electrocatalyst. Results show that Bi can be doped successfully into TiO₂ from 1% to 90%. The electrical conductivity of a 1% Bi-doped TiO₂ particle-suspended solution is increased nearly twice that of pure TiO₂. The electro-catalyzing property of the synthesized Bi-doped TiO₂ catalyst was performed under acidic conditions toward a methyl blue dye solution. The observed removal percentage of methyl blue dye was from 5% to 75%. The optimized electro-catalyzing condition was observed at 5% Bi-doped TiO₂ with a working voltage of 5 V.     

An ecofriendly approach for corrosion control of 6061 Al-15％(v) SiC(p) composite and its base alloy

Corrosion inhibition characteristics of bio polymer dextran was studied for the corrosion control of 6061 Al-15%_((v)) SiC_((P)) composite and its base alloy in 1 mol·L~(-1) HCl. Standard electrochemical techniques such as potentiodynamic polarization(PDP) measurements and electrochemical impedance spectroscopy(EIS) method were adopted for corrosion rate measurement. Surface morphology was studied by scanning electron microscopy(SEM) and elemental mapping was done by energy dispersive X-ray(EDX) analysis. Suitable mechanism was proposed for corrosion and inhibition process. Results indicated that dextran acts as an excellent anticorrosive agent for the corrosion control of 6061 Al-15%_((v)) SiC_((P)) composite, with maximum inhibition efficiency of 91% for the concentration of 0.4 g·L~(-1) at 303 K. Dextran acted as a mixed type of inhibitor, and got physically adsorbed both on composite and base alloy by obeying Langmuir adsorption isotherm. Dextran is proved to be a green inhibitor with environmental and economic benefits.     

GC–MS analysis of oxysterols and their formation in cultivated liver cells (HepG2)

Oxysterols play a key role in many (patho)physiological processes and they are potential biomarkers for oxidative stress in several diseases. Here we developed a rapid gas chromatographic-mass spectrometry-based method for the separation and quantification of 11 biologically relevant oxysterols bearing hydroxy, epoxy, and dihydroxy groups. Efficient chromatographic separation (resolution ≥ 1.9) was achieved using a medium polarity 35%-diphenyl/65%-dimethyl polysiloxane stationary phase material (30 m × 0.25 mm inner diameter and 0.25 μm film thickness). Based on thorough analysis of the fragmentation during electron ionization we developed a strategy to deduce structural information of the oxysterols. Optimized sample preparation includes (i) extraction with a mixture of n-hexane/iso-propanol, (ii) removal of cholesterol by solid phase extraction with unmodified silica, and (iii) trimethylsilylation. The method was successfully applied on the analysis of brain samples, showing consistent results with previous studies and a good intra- and interday precision of ≤20%. Finally, we used the method for the investigation of oxysterol formation during oxidative stress in HepG2 cells. Incubation with tert-butyl hydroperoxide led to a massive increase in free radical formed oxysterols (7-keto-chol > 7β-OH-chol >> 7α-OH-chol), while 24 h incubation with the glutathione peroxidase 4 inhibitor RSL3 showed no increase in oxidative stress based on the oxysterol pattern. Overall, the new method described here enables the robust analysis of a biologically meaningful pattern of oxysterols with high sensitivity and precision allowing us to gain new insights in the biological formation and role of oxysterols.     

Evolution of structural,magnetic and magnetocaloric effect in TmFe1-xMnxO3 (x≤0.3)

The influence of Mn doping on structure, magnetic behaviors and magnetocaloric effect in TmFeO₃ polycrystalline ceramics has been explored. X-ray powder diffraction proves that TmFe_1-xMn_xO₃ (x ≤ 0.3) ceramics maintain an orthorhombic structure, and the space group is Pbnm. Compared with the original TmFeO₃ sample, structural parameters change slightly and magnetic properties are effectively tuned with the gradual substitution of Mn at Fe site. The spin reorientation temperature region shifts from 90.3 to 73.2 K for TmFeO₃ to 180.0–156.0 K for TmFe_0.7Mn_0.3O₃. Besides, for TmFe_1-xMn_xO₃ (x ≤ 0.3), the maximum magnetic entropy changes dependent on the Mn composition are 6.29 J/kg K, 6.56 J/kg K, 6.79 J/kg K and 7.22 J/kg K for 0–70 kOe, respectively. The refrigeration capacities are 159.3 J/kg, 168.9 J/kg, 176.7 J/kg and 184.4 J/kg, respectively. For a better assessing the magnetocaloric performance of TmFe_1-xMn_xO₃ (x ≤ 0.3), we have calculated the temperature average entropy change, refrigerant capacity and normalized refrigerant capacity, and their values become larger with increasing Mn doping. Our experimental results can provide valuable references for the application and development of RFeO₃ (R = rare earth) as multifunctional materials.     

Asymmetric biphasic hydrophobic/hydrophilic poly(lactic acid)–polyvinyl alcohol meshes with moisture control and noncytotoxic effects for wound dressing applications

A noncytotoxic film was developed in this work with asymmetric biphasic properties (hydrophilic/hydrophobic) that allow for gas exchange. Among its many biomedical applications, it could be applied as a wound dressing material where the absorption of exuded fluids and control of water loss is required simultaneously. Thin meshes were developed modifying one face of poly(lactic acid) (PLA) electrospun mats with polyvinyl alcohol (PVA) using a simple photografting methodology. The contact angle of the modified face of the film was 44° while that of the other face was the original value of 122°. The chemical modification was covalent, as confirmed by X-ray photoelectron spectroscopy, stable over time and resistant to successive washing steps. Cytotoxic assays with fibroblast cells showed that PVA photo-grafted onto PLA meshes present a high cell viability percentage. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47369.     

Non-enzymatic and enzymatic degradation of poly(ethylene glycol)-b-poly(?-caprolactone) diblock copolymer micelles in aqueous solution

The non-enzymatic and enzymatic degradation behaviors of the monomethoxy-poly(ethylene glycol)-b-poly(?-caprolactone) diblock copolymers (MPEG-PCL) micelles in aqueous solution were investigated by DLS, ¹H NMR, SEC and HPLC. It is found that the degradation mechanism of MPEG-PCL micelles in aqueous solution in non-enzymatic case is quite different from that in the presence of enzyme. In non-enzymatic case, the degradation induced by acidic catalysis was not found in low pH aqueous solution but the degradation of the micelles occurred under neutral and basic conditions. The degradation of MPEG-PCL micelles first happens near the interface region of the MPEG shell and PCL core, leading to the part detachment of PEG chains. With increasing degradation time, the degradation inside the PCL core with a random scission on PCL chains occurred. Compared with non-enzymatic degradation, the enzymatic degradation of MPEG-PCL micelles is much fast and the degradation rate of MPEG-PCL micelles is proportional to either the micelles or the enzyme concentration in a certain range. Based on the micelle degradation behaviors that we observed, a possible mechanism for the enzymatic degradation of the MPEG-b-PCL micelles including PCL core erosion which results in cavitization of micellar core and micellar dissociation is proposed.     

Static magnetic field-assisted synthesis of Fe_3O_4 nanoparticles and their adsorption of Mn(Ⅱ) in aqueous solution

A facile method for synthesis of the magnetic Fe_3O_4 nanoparticles was introduced.Magnetic nanoparticles were prepared via co-precipitation method with(PMF) and without(AMF) 0.15 T static magnetic field.The effects of magnetic field on the properties of magnetic nanoparticles were studied by XRD,TEM,SEM,VSM and BET.The results showed that the magnetic field in the co-precipitation reaction process did not result in the phase change of the Fe_3O_4 nanoparticles but improved the crystallinity.The morphology of Fe_3O_4 nanoparticles was varied from random spherical particles to rod-like cluster structure.The VSM results indicated that the saturation magnetization value of the Fe_3O_4 nanoparticles was significantly improved by the magnetic field.The BET of Fe_3O_4nanoparticles prepared with the magnetic field was larger than the control by 23.5%.The batch adsorption experiments of Mn(Ⅱ) on the PMF and AMF Fe_3O_4 nanoparticles showed that the Mn(II) equilibrium capacity was increased with the pH value increased.At pH 8,the Mn(Ⅱ) adsorption capacity for the PMF and AMF Fe_3O_4 was reached at 36.81 and 28.36 mg·g~(-1),respectively.The pseudo-second-order model fitted better the kinetic models and the Freundlich model fitted isotherm model well for both PMF and AMF Fe_3O_4.The results suggested that magnetic nanoparticles prepared by the magnetic field presented a fairly good potential as an adsorbent for an efficient removal of Mn(Ⅱ) from aqueous solution.