The effect of soil P sorption properties and phosphorus fertiliser application strategy on ‘incidental’ phosphorus fertiliser characteristics: a laboratory study

The application of phosphorus (P) fertilisers to grazed pasture systems can increase the export of P in surface runoff. This increase can arise from interaction of recently applied fertiliser P with surface runoff (incidental effects) or the interaction between pseudo-equilibrated soil P and surface runoff (systematic effects). The former can represent a large proportion of annual exports. In this paper we investigate the effect of soil P buffering properties and fertiliser application strategy—split versus single applications—on incidental fertiliser effects, using laboratory studies. We used a weak electrolyte solution as a surrogate measure of runoff P and consequently defined ‘fertiliser half-life’ for six soils with widely differing P buffering properties. There was a significant (P < 0.01) exponential decay relationship between soil P buffering and fertiliser half life. For soils with low P buffering capacity, fertiliser half life was up to ~4 days, whereas for highly P buffered soils the half life was <0.5 day. There was also a highly significant (P < 0.01) effect of P buffering capacity on the magnitude of the incidental fertiliser effect, with the magnitude increasing as P buffering decreased. On one of our soils with buffering properties typical of soils used for dairying in SE Australia, we compared the effect on soluble P of a single application of 40 kg P ha⁻¹ with three applications of 13 kg P ha⁻¹. A simple comparative measure of the risk associated with the two fertiliser strategies—the area under the time by concentration curves—suggests that there is greater risk with a single application. Our results show that particular attention should be paid to timing of P fertiliser application on poorly buffered soils.     

The effect of extraction condition on ‘HyperCoal’ production (1)—under room-temperature filtration

In order to produce ashless coal (HyperCoal) in a high yield, extractions with several organic solvents—tetralin, 1-methylnaphthalene, dimethylnaphthalene and light cycle oil (LCO) at 200–380 °C were conducted for various ranks of coals, and subsequent solid/solution separation was done at room temperature. LCO was found to be a useful, cost-effective solvent, since it gave similar extraction yields to three other reagent solvents. The extraction yield for Illinois No. 6 coal gradually increased over 200 °C, and a significant increase in extraction yield was observed from 350 to 360 °C. We succeeded in producing ashless coal with less than 0.1% in ash content for seven of nine coals used in this study.     

Polypropylene (PP)–Acacia mangiumcomposites: the effect of acetylation on mechanical and water absorption properties

Acacia mangiumwood flour (AMWF)–polypropylene (PP) composites were produced at different filler loading (20, 30, 40, and 50 w/w) and mesh no. (35, 60, 80, and 100 mesh). The AMWF–PP composites (using unmodified or modified wood flour) were compounded using a Haake Rheodrive 500 twin screw compounder. The mechanical and water absorption (WA) properties of modified (only at mesh no. 100) and unmodified AMWF–PP composites were investigated. Increase in the mesh number (35–100) of the unmodified AMWF showed increased flexural and impact properties. Flexural modulus exhibited higher properties as the filler loading increased (20–50). However, flexural and impact strength showed the opposite phenomenon. Water absorption and thickness swelling increased as the mesh number and filler loading increased. This has been attributed to the presence of hydrophilic hydroxyl groups of the filler. Modified AMWF–PP composites exhibited higher mechanical properties and good water resistance when compared to unmodified AMWF–PP composites at all values of filler loading. The evidence of the failure mechanism (from impact strength) of the filler–matrix interface was analyzed using scanning electron microscope.     

Gasification of Brazilian coal-chars with CO2: effect of samples’ properties on reactivity and kinetic modeling

The gasification of coals obtained from important coalfields in Brazil was investigated in 1.0?bar of CO₂ using a thermogravimetric analyzer. Tests were carried out in two sequential steps: pyrolysis under N₂ at 1213 K and isothermal gasification under CO₂ in the temperature range of 1113–1213 K. The kinetic study was performed in the kinetically controlled regime and three gas-solid models were fitted to the experimental data. According to the results, subbituminous coal-chars presented higher reactivities than bituminous types, with maceral and ash compositions playing a key role in the overall process. The reaction rates increased with increasing temperature, with maximum values found in the conversion range of 10–60%. The random pore model that predicts a maximum point of reactivity over the reaction course suitably described the gasification kinetics. Values of activation energy between 146.63(±0.03) kJ/mol and 215.09(±0.05) kJ/mol were found, which are consistent to literature data of coals gasified worldwide. Despite the relatively high ash content (32–45%), the Brazilian coals appeared to be sufficiently reactive to be gasified, thus indicating the significance of this study to the development of gasification process in Brazil.     

Effects of conservation tillage,crop residue and cropping systems on changes in soil organic matter and maize–legume production: a case study in Teso District

The effects of conservation tillage, crop residue and cropping systems on the changes in soil organic matter (SOM) and overall maize–legume production were investigated in western Kenya. The experiment was a split-split plot design with three replicates with crop residue management as main plots, cropping systems as sub-plots and nutrient levels as sub-sub plots. Nitrogen was applied in each treatment at two rates (0 and 60 kg N ha⁻¹). Phosphorus was applied at 60 kg P/ha in all plots except two intercropped plots. Inorganic fertilizer (N and P) showed significant effects on yields with plots receiving 60 kg P ha⁻¹ + 60 kg N ha⁻¹ giving higher yields of 5.23 t ha⁻¹ compared to control plots whose yields were as low as 1.8 t ha⁻¹ during the third season. Crop residues had an additive effect on crop production, soil organic carbon and soil total nitrogen. Crop rotation gave higher yields hence an attractive option to farmers. Long-term studies are needed to show the effects of crop residue, cropping systems and nutrient input on sustainability of SOM and crop productivity.     

Correct use of the Langmuir–Hinshelwood equation for proving the absence of a synergy effect in the photocatalytic degradation of phenol on a suspended mixture of titania and activated carbon

This study is a critical approach to the widespread use of the first order form of the Langmuir–Hinshelwood (LH) equation for analyzing kinetics in heterogeneous photocatalytic processes. The different kinetic protocols analyzed have been applied to the results, published in the literature, of the photocatalytic degradation of phenol in an aqueous solution by a physical mixture of TiO₂ particles and activated carbon (AC), the impact of which has been enormous over the last decade. It is commonly accepted that there is a strong synergy in this mixture due to the transfer of phenol from the activated carbon particles to TiO₂. However, we found in this study that the apparent synergy between activated carbon and TiO₂ particles arises from the erroneous use of the first order form of the LH equation. When applying the extended form of the LH equation, that includes the inhibitory effect of the phenol concentration, AC/TiO₂ synergy should be disregarded. In this physical mixture the activated carbon merely alleviates the inhibitory effect of the phenol concentration by decreasing its initial value.     

A comparative study between three different methods of hydrogel network characterization: effect of composition on the crosslinking properties using sol–gel,rheological and mechanical analyses

Polymer Bulletin - Previously, different techniques were used to identify the crosslinking density of hydrogels. In this study, we aimed to compare three different methods of network structure...     

Effects of 15 years of manure and inorganic fertilizers on soil organic carbon fractions in a wheat-maize system in the North China Plain

Soil organic carbon (SOC) and its labile fractions are strong determinants of chemical, physical, and biological properties, and soil quality. Thus, a 15-year experiment was established to assess how diverse soil fertility management treatments for winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) cropping system affect SOC and total N (TN) concentrations in the North China Plain. The field experiment included three treatments: (1) unfertilized control (CK); (2) inorganic fertilizers (INF); and (3) farmyard manure (FYM). Concentrations of SOC, TN, and different labile SOC fractions were evaluated to 1-m depth. In comparison with INF and CK, FYM significantly increased SOC and TN concentrations in the 0–30 cm depth, and also those of dissolved organic C (DOC), microbial biomass C (MBC), hot-water extractable C (HWC), permanganate oxidizable C (KMnO₄–C), and particulate organic C (POC) in the 0–20 cm depth. Despite the higher crop yields over CK, application of INF neither increased the SOC nor the labile C fractions, suggesting that by itself INF is not a significant factor affecting SOC sequestration. Yet, POC (18.0–45.8% of SOC) and HWC (2.0–2.8%) were the most sensitive fractions affected by applications of FYM. Significantly positive correlations were observed between SOC and labile organic C fractions in the 0–20 cm depth. The data support the conclusion that, wherever feasible and practical, application of FYM is important to soil C sequestration and improving soil quality under a wheat/maize system in the North China Plain.     

APS-silane modification of silica nanoparticles: effect of treatment’s variables on the grafting content and colloidal stability of the nanoparticles

Silica nanoparticles, Aerosil 200, with an average primary particle size of 12 nm were chemically modified by γ-aminopropyltriethoxy silane (APS) via a two-step sol–gel process. Effects of the treatment variables including reaction temperature, water content, and silane concentration on the colloidal stability and the amount of APS grafting on the surface of nanoparticles were studied using thermal gravimetric analysis, diffuse reflectance infrared spectroscopy, and by monitoring the sedimentation behavior of the dispersion of nanoparticles in distilled water as a polar media. Furthermore, the effect of surface modification on the dispersibility of silica nanoparticles in an epoxy novolac coating was evaluated by means of scanning electron microscopy. The results showed chemical interactions between APS and SiO₂ nanoparticles. Also, parameters including treatment at ambient temperature, low level of water, and moderate concentration of silane compound, have a considerable effect on the APS grafting content due to the increase of silane hydrolysis and higher silylation coverage of the nanoparticles.     

Study on the effect of Ti,Al, Cu,and Ag doping on the bonding properties of soldered β-Sn(100)/ZrO2(111) interface

Selecting active elements for filler metal is very important in soldering of ZrO₂ ceramics. In this paper, the effects of Ti, Al, Cu, and Ag active elements on the bonding strength and electronic structures of soldered β-Sn(100)/ZrO₂(111) interface were studied via the method of first principle calculation. The work of adhesion (W_ad) results show that the O₂-terminated interface is more stable than other kinds of interfaces. Then, the atoms of Ti, Al, Cu, and Ag were doped into the interface by replacing the Sn atom in situ. It is found that additions of Ti, Al, and Cu atoms can increase the W_ad, and Ag atom has the opposite effect. From the results of heat of segregation, doping Ti and Al into the interface is stable in thermodynamics and doping Cu and Ag is not stable. The forming of strong ionic-covalent Ti-O and Al-O bonding contributes to the increase of the interfacial adhesion strength. The calculation results indicate that Ti and Al can act as active elements in Sn to solder ZrO₂. The Ti-O and Al-O compounds formed at interface can improve the wetting and bonding between Sn-based solder and ZrO₂ ceramics.     

Can litter production and litter decomposition improve soil properties in the rubber plantations of different ages in Côte d’Ivoire?

Litter production and litter decomposition influence the availability of nutrients in the soil. The investigation aimed at characterizing the dynamics of leaf litter decomposition, and soil physico-chemical and biological parameters in rubber plantations of different ages. During a 12-months’ period, field studies were done in 7-, 12-, and 25-year-old rubber plantations. For measuring of litter decomposition and input from aboveground, 324 litter bags and 27 litter traps (1 m?×?1 m) were placed in 3 sampling areas per age class of rubber plantations. The soil parameters were also characterized. The results showed that the annual litter production and the amounts of organic carbon in leaves increased with the aging of the plantations. The annual decomposition constant (k) ranged from 0.0381?±?0.0040 year^?1 in the 25-year-old plantations to 0.0767?±?0.0111 year^?1 in the 7-year-old plantations. The annually decomposed litter mass varied between 2.7?±?0.3 t ha^?1 year^?1 in the 12-year-old plantations to 4.2?±?0.3 t ha^?1 year^?1 in the 25-year-old plantations. The soil of the 25-year-old plantations showed higher values of most physico-chemical and biological variables as compared to the 7-year-old plantations: annual litter production (+?32%), annual litter mass decomposed (+?11%), annual carbon (+?15%) and nitrogen (+?11%) inputs, soil organic carbon (+?52%), total nitrogen (+?32%), soil organic matter (+?52%), soil water content (+?74%), and the total density of soil invertebrates (+?121%). The results indicate an improvement of soil properties with the aging of the rubber plantations and the importance of this agricultural system for carbon sequestration.     

The effect of chemistry on the polymerization, thermo-mechanical properties and degradation rate of poly(β-amino ester) networks

Poly(β-amino ester) networks are gaining attention as a scaffold material for tissue engineering applications where it is important to have tailorable degradation rate and elastic modulus. The objective of this work is to characterize and understand the relationships between chemical structure, polymerization, thermo-mechanical properties, and degradation in poly(β-amino esters) networks. The networks were synthesized from a primary amine with systematically varied molar ratios and chemical structures of diacrylates. Fundamental trends were established between the chemical structure, conversion during polymerization, macromer molecular weight, rubbery modulus, and degradation rate. The thermo-mechanical properties were dependent upon both polymerization steps. The rubbery modulus was tailorable over a range of several MPa by changing molar ratio and diacrylate molecular weight. The degradation rate ranged from hours to months depending upon the composition. Select chemical structures showed degradation rate independent of modulus. This work provides a basis for designing poly(β-amino esters) networks with specific thermo-mechanical properties and degradation rates for biomedical scaffolds.     

Synthesis and characterisation of silica–carbon nanotube hybrid microparticles and their effect on the electrical properties of poly(vinyl alcohol) composites

Hybrid silica–carbon nanotube (CNT) particles with a radial symmetry were produced by the growth of nanotubes onto spherical, mesoporous silica gel particles using the floating catalyst chemical vapour deposition (FC-CVD) method. Characterisation of the hybrid particles, using electron microscopy, Raman spectroscopy and thermogravimetry showed the geometry and porosity of the silica particles to influence the alignment and density of the CNTs produced. CNT growth initiated in the pores of the gel particles and three hours of CVD growth were required to get extensive surface coverage. In the early stages of growth, the reactants diffused inside the mesoporous silica and consequently the CNTs grew mainly within the silica gel rather than on the surface. Some indication of catalyst templating was observed within the smaller (<10 nm) pores, but this templating did not result in aligned CNTs. Composite films of hybrid silica–CNT particles in poly(vinyl alcohol) were cast and their impedance measured. An electrical percolation threshold of 0.62 wt.% was found for the hybrid particles, of which 0.20 wt.% were CNTs.     

Effect of codoping Ce3+ on the luminescence properties of Sr9Mg1.5(PO4)7:Eu2+ orange–yellow phosphor

Sr₉Mg_1.5(PO₄)₇:Eu²⁺ has recently been reported as a promising blue light-excited orange–yellow phosphor that can be used in white LED device. Here, Ce³⁺-codoping is found to be an effective strategy to improve the luminescence performance of Sr₉Mg_1.5(PO₄)₇:Eu²⁺ phosphor. The coexistence of Eu²⁺ and Eu³⁺ ions has been verified via photoluminescence spectral analysis. The reduction of Eu³⁺ to Eu²⁺ in Sr₉Mg_1.5(PO₄)₇ lattice cannot be completed in a reducing atmosphere, but can be promoted through codoping with Ce³⁺ ions to a great extent, which finally increase the effective concentration of Eu²⁺ in the crystal lattice. The Eu³⁺−Eu²⁺ reduction mechanism is analyzed using a charge compensation model. This work not only achieves enhanced luminescence of the Sr₉Mg_1.5(PO₄)₇:Eu²⁺ phosphor by codoping with Ce³⁺ ions, but also provides new insights into the design of Ce³⁺/Eu²⁺ codoped luminescent materials.     

The influence of the mixed alkaline earth effect on the structure and properties of (Ca,Mg)–Si–Al–O–N glasses

Alkaline earth oxynitride glasses of (Ca, Mg)–Si–Al–O–N with different CaO/(CaO + MgO) molar ratios (0, 0.25, 0.5, 0.75, and 1) were successfully prepared using the sol-gel method, and their structural compositions were characterised by Raman and FT-IR techniques. The glass dynamic properties of thermal expansion coefficient, glass transition temperature (T_g), and static properties of density, molar volume, Vickers hardness and compressive strength were systematically measured and analysed. The results showed that the static properties exhibited an overall regular change as the CaO/(CaO + MgO) ratio gradually increased, while the dynamic properties had an obvious mixed alkaline earth effect, which represented the appearance of an extreme value point in CaO/(CaO + MgO) mole ratios of 0.25 and 0.75, respectively. The typical thermal expansion coefficient and T_g of mixed alkaline earth oxynitride glasses deviated far from the linear connection between single alkaline earth oxynitride glasses. Raman spectra and infrared spectra revealed that the ratio value of the Q³/(Q²+Q⁴) decreased (Qⁿ: n = no. of bridging anions joining SiO₄ tetrahedra) in the mixed alkaline earth oxynitride glasses with increasing the amount of Ca, confirming that Ca decreased the crosslinking between individual tetrahedra via the transformation of Q³ species into Q² and Q⁴ species.     

Bis(thien-2-yl)-2,1,3-benzothiadiazole-diketopyrrolopyrrole-based acceptor–acceptor conjugated polymers: Design,synthesis, and the synergistic effect of the substituent on their solar cell properties

Three acceptor–acceptor conjugated copolymers ( TBT-DPP , FTBT-DPP , and HFTBT-DPP ) with different substituent groups have been synthesized with palladium-catalyzed Stille coupling condensation polymerization assisted with microwave. Polymer solar cells (PSCs) based on these copolymers as the electron donors and PC71BM as the acceptor have been fabricated. The synergistic effect of the substituent between two fluorine atoms and hexyl alkyl chains in bis(thien-2-yl)-2,1,3-benzothiadiazole fragment on their solar cell properties has been investigated. Both the fluorine atoms and the synergistic effect can improve the solubility of the polymers effectively while the excellent thermal stability properties are still retained. Two fluorine atoms (polymer FTBT-DPP ) increased the power conversion efficiency of the PSCs twice compared with TBT-DPP (without substituent). The synergistic effect (polymer HFTBT-DPP ) decreased that seriously to zero. Density function theory calculations showed that the conjugation level of the polymer backbone is one of key factors. It demonstrates that the synergistic effect of fluorine atoms and alkyl chains in the same fragment does not always work well in improving the PSCs performance.     

Influence of the batch’s ash content on coke quality (CRI and CSR)

To permit more precise assessment of Russia’s coal reserves, the influence of the batch’s ash content on the reactivity (CRI) and postreactive strength (CSR) of the coke produced is analyzed.     

Supported Ziegler type catalysts for production of polyethylene (PE): Effect of the composition of the active component,the methods of its formation,and the use of modifying agents on catalytic activity and molecular structure of PE and copolymers of ethylene with α-olefins

Summarized results are presented from studying the formation of the active component of supported Ziegler type catalysts, investigating the effect of the composition of these catalysts on the molecular mass characteristics of PE, and seeking new methods for producing catalysts with optimum morphology.