Advances in membrane emulsification. Part A: recent developments in processing aspects and microstructural design approaches

Modern emulsion processing technology is strongly influenced by the market demands for products that are microstructure‐driven and possess precisely controlled properties. Novel cost‐effective processing techniques, such as membrane emulsification, have been explored and customised in the search for better control over the microstructure, and subsequently the quality of the final product. Part A of this review reports on the state of the art in membrane emulsification techniques, focusing on novel membrane materials and proof of concept experimental set‐ups. Engineering advantages and limitations of a range of membrane techniques are critically discussed and linked to a variety of simple and complex structures (e.g. foams, particulates, liposomes etc.) produced specifically using those techniques. © 2013 Society of Chemical Industry     

Eye-blink detection system for human–computer interaction

A vision-based human--computer interface is presented in the paper. The interface detects voluntary eye-blinks and interprets them as control commands. The employed image processing methods include Haar-like features for automatic face detection, and template matching based eye tracking and eye-blink detection. Interface performance was tested by 49 users (of which 12 were with physical disabilities). Test results indicate interface usefulness in offering an alternative mean of communication with computers. The users entered English and Polish text (with average time of less than 12s per character) and were able to browse the Internet. The interface is based on a notebook equipped with a typical web camera and requires no extra light sources. The interface application is available on-line as open-source software.     

On the tungsten carbide synthesis for PEM fuel cell application – Problems,challenges and advantages

Fuel cell application of tungsten carbide is revisited starting with four different tungsten carbide precursors used for high temperature synthesis. It was shown that the final products greatly depend on the nature of the precursor. Using tungsten peroxide/2-propanol derived precursor almost pure WC was obtained which was subjected to further electrochemical investigation. It was shown that it is necessary to decorate WC with Pt nanoparticles in order to obtain satisfactory fuel cell performance, but catalytic activity of Pt/WC anode catalyst is not expected to overcome the activity of Pt/C. It is argued that new synthetic routes for the preparation of WC should be directed towards obtaining highly dispersed WC, that is, WC with high external surface area available for Pt deposition, rather than high specific surface area WC with large contribution of micropores having no importance when it comes to the use of WC as a catalyst support. The true benefit of the use of WC as catalyst support is found in increased CO tolerance/CO oxidation activity of WC-supported Pt catalysts. Qualitative mechanistic view on increased CO oxidation activity of Pt/WC is offered.     

Microstructure and tribological properties of low-friction composite MoS2(Ti,W) coating on the oxygen hardened Ti-6Al-4V alloy

Duplex surface treatment, which combines the oxygen diffusion hardening with a deposition of low friction MoS₂(Ti,W) coating, was applied to improve the Ti-6Al-4V alloy load bearing capacity and tribological properties. The coating (3.1 μm thick) was deposited on the oxygen hardened alloy by magnetron sputtering. Microstructure characterisation was performed by scanning- and transmission electron microscopy methods, as well as X-ray diffractometry. The results of micro/nanostructural analyses performed by high-resolution transmission electron microscopy showed that the coatings are composed of MoS₂ nanoclusters embedded in an amorphous matrix. Some Ti α, W, and Ti₂S nanocrystals were also found in the coating microstructure. The wear resistance and friction coefficient of the hardened oxygen, as well as the coated alloy, was investigated at room temperature (RT), 300 °C, and 350 °C. The presence of the MoS₂(Ti,W) coating decreases the friction coefficient from 0.85 for the oxygen hardened alloy to 0.15 (at RT) and 0.09 (at 300 °C and 350 °C) for the coated one. The coating essentially increases the wear resistance of the alloy at RT and 300 °C. It was found that the wear resistance of the coated alloy decreased significantly during the wear test performed at 350 °C.     

Luminescent cellulose fibers modified with cerium fluoride doped with terbium particles

This article describes UV‐active cellulose fibers obtained by dry‐wet spinning method. The fibers have been formed from an 8% by weight cellulose solution in N‐methylomorpholine‐N‐oxide (NMMO) modified by Ce_0.85Tb_0.15F₃ nanocrystals. The modifier was synthesized by wet chemical method, coprecipitation approach. The host was chosen as the most promising one for the green emitting Tb³⁺ ions. Photoluminescent nanoparticles were introduced into the polymer matrix during the process of dissolving cellulose in NMMO. The modifier occurred in the form of white paste, consisting of luminescent nanoparticles dispersed in glycerine. The dependencies between the concentration of nanocrystals, emission intensity, and excitation energy of the final cellulosic luminescent products were examined by photoluminescence spectroscopy. The size and structure of Ce_0.85Tb_0.15F₃ nanocrystals were studied by X‐ray powder diffraction analysis. The dispersion of the nanoparticles in the polymer matrix was evaluated using scanning electron microscopy and transmission electron microscopy. The real content of luminescent nanocrystals in the fibers was estimated as well. The influence of different concentrations of modifier particles (in the range from 0.5 to 5% by weight) on the mechanical properties of the fibers was determined. POLYM. COMPOS., 153–160, 2016. © 2014 Society of Plastics Engineers     

Effect of organic load on phosphorus and bacteria removal from wastewater using alkaline filter materials

The organic matter released from septic tanks can disturb the subsequent step in on-site wastewater treatment such as the innovative filters for phosphorus removal. This study investigated the effect of organic load on phosphorus (P) and bacteria removal by reactive filter materials under real-life treatment conditions. Two long-term column experiments were conducted at very short hydraulic residence times (average ∼5.5 h), using wastewater with high (mean ∼120 mg L⁻¹) and low (mean ∼20 mg L⁻¹) BOD₇ values. Two alkaline filter materials, the calcium-silicate material Polonite and blast furnace slag (BFS), were tested for the removal capacity of total P, total organic carbon (TOC) and Enterococci. Both experiments showed that Polonite removed P significantly (p < 0.01) better than BFS. An increase in P removal efficiency of 29.3% was observed for the Polonite filter at the lower concentration of BOD₇ (p < 0.05). Polonite was also better than BFS with regard to removal of TOC, but there were no significant differences between the two filter materials with regard to removal of Enterococci. The reduction in Enterococci was greater in the experiment using wastewater with high BOD₇, an effect attributable to the higher concentration of bacteria in that wastewater. Overall, the results demonstrate the importance of extensive pre-treatment of wastewater to achieve good phosphorus removal in reactive bed filters and prolonged filter life.     

SPG rotating membrane technique for production of food grade emulsions

A SPG rotating membrane device was used to produce food grade O/W emulsions. The emulsion droplet size: (i) decreases with increasing rotational velocity (RV), due to higher detaching drag force acting on the droplets, and (ii) increases with increasing trans-membrane pressure (TMP), due to higher interface formation rate.     

Chemical Profile of Satureja Kitaibelii Wierzb. ex Heuff. Essential Oils: Composition of Satureja Kitaibelii Essential Oils

The essential oils from dried aerial parts of Satureja kitaibelii Wierzb. ex Heuff., collected at three various sites in Serbia, were analyzed by gas chromatography and gas chromatography/mass spectrometry. One hundred sixty-three components were identified in all investigated samples, 132 components in the oil from the site Devoja?ki grob, 124 components in the oil coming from Si?eva?ka klisura site, and 146 components in the oil from the site Viso?ka R?ana, accounting 97.3, 93.9, and 95.6% of the total oils, respectively. The most abundant component in the essential oils was geraniol amounting from 24.0 to 30.3%, making up about one-quarter of the total oils. Other representative compounds were identified as linalool (5.0–14.8%), limonene (4.3–7.9%), and caryophyllene oxide (4.4–5.2%) in all tested samples. The results suggested that essential oils of S. kitaibelii belong to the aliphatic monoterpene chemotype.