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The purpose of the project was to evaluate and demonstrate new solutions for decreasing the discharges from on‐site wastewater treatment plants.

The study evaluated several on‐site wastewater treatment plants. Seven of the investigated facilities were package plants, two were urine separating plants with large sand filters, two had storage tanks to collect wastewater separated from toilets and compact sand filters, and, finally, four had chemical precipitation in combination with large sand filters.

All of the systems have shown that they are able to remove more than 90 per cent of the phosphorus and more than 90 per cent of the organic matter. The sorting systems also give very low local emissions of nitrogen. To guarantee that the package plants perform well and manage to fulfil high reduction demands, there is a need for well functioning organisations for supervision and operation. The source separating systems require well‐informed and motivated users to achieve low discharges.

This study has been followed with great interest by national and local environmental authorities. Such ambitious evaluation of different on‐site wastewater treatment systems has never been done before in Sweden. The Swedish Environmental Protection Agency is expected to soon publish new demands for these systems. The results from the project have been an important input for the proposal of new national regulations.

The spinel NiFe₂O₄ has been identified as being a potentially successful anti‐corrosion ceramic that can be used in aluminium electrolysis under molten salt corrosive conditions (970°C). The evaluation and fabrication processing of NiFe₂O₄ has been studied in this paper. According to the analysis and comparison of material properties, it has been concluded that fabrication technology for making anti‐corrosion electrode material would not be exceptionally difficult and therefore that the material has a strong potential for use in this service.

Atmospheric precipitation samples collected by a network of eight stations throughout the Kano metropolis were analysed for lead, chromium, copper, cadmium, zinc and nickel by atomic absorption. Values from all the stations averaged over approximately five months each year between 1993 and 1996 indicate human activity, the high temperatures reached by soils and the strong diurnal thermic turbulence resulting from these, as the primary source of these metals in atmospheric precipitation. The concentrations of lead, chromium and copper correlated with the industrial activities of the metropolis. Maximum concentrations of lead, copper, chromium and nickel were above 1.1μg/litre while cadmium and zinc were below the 0.11μg/litre.

The purpose of this paper is to investigate the combined effects of viscous dissipation and Newtonian heating on boundary-layer flow over a flat plate for three types of water-based nanofluids containing metallic or nonmetallic nanoparticles such as copper (Cu), alumina (Al2O3), and titania (TiO2) for a range of nanoparticle volume fractions.

The governing partial differential equations are transformed into ordinary differential equations using a similarity transformation, before being solved numerically by a Runge-Kutta-Fehlberg method with shooting technique.

It is found that the heat transfer rate at the plate surface increases with increasing nanoparticle volume fraction and Biot number, while it decreases with the Brinkmann number. Moreover, the heat transfer rate at the plate surface with Cu-water nanofluid is higher than that of Al2O3-water and TiO2-water nanofluids.

The heat transfer enhancement performances presented by nanofluids have led to innovative way of improving the thermal conductivities of working media in engineering and industries. This work provides a very useful source of information for researchers on this subject.

This paper illustrates the combined effects of viscous dissipation and Newtonian heating on boundary-layer flow of nanofluids past a flat plate.

The present work aims to deal with ultrasound-assisted organic pigment (phthalocyanine blue and green) dispersion and its comparison with the conventional approach.

Ultrasound is expected to give beneficial results based on the strong shear forces generated by cavitational effects. The dispersion quality for preparation using an ultrasound-based method has been compared with dispersion obtained using high-speed dispersion mill. Effects of different operating parameters such as probe diameter and use of surfactants on the physical properties of dispersion and the colour strength have been investigated. Calculations for the energy requirement for two approaches have also been presented.

The use of sodium dodecyl sulphate and Tween 80 surfactants shows better performance in terms of the colour properties of dispersion prepared in water and organic solvent, respectively. Ultrasound gives better dispersion quality as compared to the conventional approach.

The present work presents a new approach of ultrasound-assisted dispersion of phthalocyanine blue and green pigments. Understanding into the effect of surfactants and type of solvent also presents new important design-related information.

The purpose of this paper is to report on a method of synthesis of TiO₂‐SiO₂ oxide composites characterised by spherically shaped particles with sizes in the micrometric ranges, which can be applied as a new generation of textile/TiO₂‐SiO₂ composites with barrier properties against UV radiation. Synthesis and characterisation of TiO2‐SiO2 oxide composites with a high degree of dispersion were performed, and their influence on the barrier properties of textile fabrics was investigated.

The precipitation was performed with the use of solutions of titanium sulphate and sodium silicate as the precipitating agent, which are cheap alternatives to organic precursors of Ti and Si. The reaction was conducted in an emulsion system, where cyclohexane was used as the organic phase and non‐ionic surfactants NP3 and NP6 as emulsifiers were applied.

The direction of substrate supply, concentration of the reagents and their ratio and other conditions of precipitation process were found to significantly affect the physicochemical parameters of the pigments obtained. A possibility is provided of manufacturing a new generation of textile/TiO2‐SiO2 composites with barrier properties against UV radiation.

Titanium sulphate, sodium silicate, cyclohexane as the organic phase, and non‐ionic surfactants NP3 and NP6 as emulsifiers, were used.

Synthesis of a new generation of textile/TiO2‐SiO2 composites with barrier properties against UV radiation has been performed. Textile fabrics modified with hybrid composites demonstrated high absorption of UV radiation over the full wavelength range.

Determination of optimum conditions of TiO2‐SiO2 oxide composites precipitation to obtain products with desired physicochemical, dispersive and structural properties. Development of nano‐structural textile composites with barrier properties, protecting against UV radiation.

The purpose of this paper is to evaluate the effect of copolymer and starting material concentrations in homogeneous precipitation synthesis of Yttria nanoparticles and red‐emitting nanophosphors Y₂O₃:Eu³⁺. N‐isopropylacrylamide and acrylic acid (NIPAM/AAc) and urea are used.

To optimise synthesis condition of Y₂O₃:Eu³⁺ nanophosphor NIPAM/AAc copolymer was used as a modifier and the effect of various concentration of yttrium ions, urea and precipitation time on size, morphology and emission spectra were investigated.

Using NIPAM/AAc copolymer shows significant improvement on size and dispersion of nanoparticles. It is found that yttrium concentration, varying between 0.006 and 0.03 M, has a profound impact on the average size of particles, which systematically increases from 65 to over 165 nm. The rate of precipitation reaction, however, is shown to be independent of yttrium concentration. In contrast, as urea concentration increases from 0.2 to 5 M, the average particle size exhibits a gradual decrease from 183 to 70 nm. At extremely high urea concentration such as 5 M, a significant level of inter‐particle agglomeration is observed.

Based on this paper, the authors have successfully prepared some promising nanophosphors. The nanoparticles are studied by X‐ray diffraction, transmission electronic microscopy, zeta sizer, Infra red and photoluminescence spectroscopy.

The purpose of this paper is to focus on the removal of copper(II) ions from aqueous model salt solution by using chitosan-coated magnetite nanoparticles.

The chitosan-coated magnetite nanoparticles were characterized using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric differential thermal analysis. The adsorption of Cu(II) by using magnetite nanoparticles as an adsorbent was investigated under different adsorption conditions. The parameters studied were contact time, adsorbent dose and initial concentrations.

The sorption capacities of prepared samples were studied for the removal of Cu²⁺ ions from aqueous model solutions with varying experimental conditions of the initial metal concentration, contact time and dosage. It is found that the removal percent of Cu²⁺ ions increases with an increase in initial metal concentration, contact time and amount of dosage.

Based on the obtained results, this study recommends that chitosan-coated magnetite nanoparticles can also be applied for removal of some heavy metal ions and/or organic compounds in aqueous solution. It is recommended that this study be shared with the polymer-based nanomaterial researchers, especially material science.

This paper aims to investigate the onset of convection, heat and mass transports in a sparse porous layer saturated with chemically reactive binary fluid mixture heated and salted from below under the influence of Soret and Dufour effects.

The Brinkman model is used for momentum equation. Linear stability analysis based on normal mode technique is used to evaluate the onset threshold for stationary and oscillatory convection. In weak-nonlinear theory, the truncated Fourier series method is used. The resulting system of differential equations is solved numerically by using the Runge–Kutta fourth-order method.

Because of the competition between the processes of thermal, solute diffusions, chemical reaction and cross-diffusions, the onset of instability is via oscillatory mode instead of stationary. The effect of dissolution/precipitation of reactive component and the cross-diffusions on the stability, heat and mass transports is investigated.

By the proper adjustment of underlying parameters, the onset of convection can either be advanced or delayed as per the requirement. Therefore, the present investigation forms a useful tool for regulating the onset of convection.

The objective of this paper is to establish a solution strategy for obtaining dual solutions, namely trivial (conventional) and nontrivial (unconventional) solutions, of coupled pore-fluid flow and chemical dissolution problems in heterogeneous porous media.

Through applying a perturbation to the pore-fluid velocity, original governing partial differential equations of a coupled pore-fluid flow and chemical dissolution problem in heterogeneous porous media are transformed into perturbed ones, which are then solved by using the semi-analytical finite element method. Through switching off and on the applied perturbation terms in the resulting perturbed governing partial differential equations, both the trivial and nontrivial solutions can be obtained for the original governing partial differential equations of the coupled pore-fluid flow and chemical dissolution problem in fluid-saturated heterogeneous porous media.

When a coupled pore-fluid flow and chemical dissolution system is in a stable state, the trivial and nontrivial solutions of the system are identical. However, if a coupled pore-fluid flow and chemical dissolution system is in an unstable state, then the trivial and nontrivial solutions of the system are totally different. This recognition can be equally used to judge whether a coupled pore-fluid flow and chemical dissolution system involving heterogeneous porous media is in a stable state or in an unstable state. The proposed solution strategy can produce dual solutions for simulating coupled pore-fluid flow and chemical dissolution problems in fluid-saturated heterogeneous porous media.

A solution strategy is proposed to obtain the nontrivial solution, which is often overlooked in the computational simulation of coupled pore-fluid flow and chemical dissolution problems in fluid-saturated heterogeneous porous media. The proposed solution strategy provides a useful way for understanding the underlying dynamic mechanisms of the chemical damage effect associated with the stability of structures that are built on soil foundations.