Spatial distibution and temporal accumulation of polychlorinated dibenzo-p-dioxins,dibenzofurans, and biphenyls in the Gulf of Finland

Dated sediment cores and surface sediments were analyzed from the Gulf of Finland, a part of the Baltic Sea, to study the sources, levels, distribution, and total amounts of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). The gulf was found to be severely polluted, with PCDD/F sum concentrations as high as 101000 ng/kg and 479 ng/kg WHO-TEQ in dry weight. The source of pollution was the former manufacturing and use of a chlorophenol based wood preservative along the Kymijoki River. It was estimated thatthe impacted sedimentary area stretched a distance of 75 km away out from the coast and that the PCDD/F sum load attributed to the wood preservative source was 1770 kg of PCDD/Fs or 12.4 (+/-2.8) kg WHO-TEQ. The surface sediments contained 24-66% of the maximum concentrations present in the 1960-1970s, showing that the river still acts as a significant PCDD/F source and may contribute to the high levels in fish. Moreover, the reduced PCDD/F and PCB concentrations were partly due to the dilution by increased dry matter deposition. PCBs were uniformly distributed over the gulf, and the PCB load in the polluted area was 2020 kg or 0.14 kg WHO-TEG.     

Investigation of the phase separation of PNIPAM using infrared spectroscopy together with multivariate data analysis

The use of vibrational spectroscopy to investigate complex structural changes in polymers yields chemically rich data, but interpretation can be challenging and subtle but meaningful spectral changes may be missed through visual inspection alone. Multivariate analysis is an efficient approach to gain an oversight of small but systematic spectral differences anywhere within the spectra, providing further insight into structural changes and associated transformation mechanisms. In this study, the novel analytical approach of infrared spectroscopy combined with principal component analysis and Gaussian peak fitting was used to investigate the structural changes in aqueous solutions of a polymer, using poly(N-isopropyl acrylamide) (PNIPAM) in the atactic form and with controlled tacticity as a model system. Subtle spectral changes associated with the dehydration and phase separation upon heating included peak shifts, an area ratio change of the amide I band to the amide II band and formation of a new peak in the amide I band were efficiently detected. Dehydration and phase separation of PNIPAM occurred in two temperature ranges, one for the atactic and one for isotactic rich part, both involving a complex re-organization of the hydrogen bonds and change of the hydration layer. The changes agreed with existing results from other techniques, and new insights were gained into the effect of controlled tacticity on phase transformation behaviour. The study demonstrates that infrared spectroscopy combined with the multivariate analytical method principal component analysis and Gaussian peak fitting is an efficient approach to probing structural change in polymers during heating. The simplicity of the presented approach could find excellent use in analysing and understanding the molecular environment of a range of stimuli-responsive polymers, for instance block or grafted types of polymers, as well as those with controlled tacticity.     

Identity and overall acceptance of two types of sour rye bread

Response surface methodology was employed to study the influence of four recipe variables (wheat: rye flour ratio, bread acidity, ash content of rye flour and sodium chloride content) on the identity and overall acceptance of two rye bread types (soft and crisp rye bread). The subjects ( n = 79) rated attribute intensities, the extent to which the salient sensory properties and the overall sample corresponded to their expectations of rye bread, and the overall acceptance (pleasantness and purchase intentions). The acidity and ash content contributed the most to the extent to which a sample met subjects' expectations. The NaCl content was not critical. Consumer acceptance was affected by ash content, and by the interactions, NaCl content × acidity and wheat:rye ratio × ash content. The non-significance of NaCl content should encourage the baking industry to put low-salt rye products on the market.     

Computerized product process: Measurement and continuous improvement

Product development has until recently been considered pure art instead of being a controllable process. However, the current competitive environment has forced companies to take a closer look in the way new products are being developed. A key element in this assessment is the development of a set of metrics, which describe the whole product development process. This article explores the data-based opportunities for continuous improvement in the product development process emerging alongside the increasing utilization of networked Information Technology (IT) applications. Based on data from information systems in the case-study companies, three different product process visualizations are presented. Each visualization is discussed both from the viewpoint of its explanatory power as well as its limitations.The results of the case-studies clearly indicate that the computerization of the engineering and design processes is generating new ways of measuring, understanding and improving product development. The appropriate measures combined with open communication and a learning environment can be used to create a cycle of continually improving the product development process.     

Grafting of unsaturated acids and silanes to ethylene polymers: A kinetic model

A general kinetic model was developed to simulate the grafting of monomers such as unsaturated carboxylic acids and silanes to ethylene polymers. The polymers considered were ethylene-co-vinyl acetate (EVA), ethylene-co-butyl acrylate (EBA), and low-density polyethylene (LDPE). Grafting was assumed to proceed by a free-radical mechanism involving chain transfer. Organic peroxides having a strong tendency for hydrogen abstraction were selected as the source of primary radicals. The model simulated the grafting reaction as taking place in a single screw extruder. The residence time distribution in the extruder was experimentally determined by tracer analysis, according to which the extruder was a plug-flow reactor connected to two mixed reactors in parallel. The model is able to predict the extent of grafting in terms of predefined parameters. Comparison of model predictions with available experimental data showed slight deviations, the possible causes of which are discussed. However, the kinetic behavior expected on the basis of the input parameters was observed, and, as such, the model allowed study of the effect of process variables on grafting kinetics and provided insight into the reaction mechanism.     

Copolymers of ethylene with butene-1 and long chain α-olefins. I. Decene-1 as long chain α-olefin

The possibility was studied of using decene-1 as comonomer with ethylene in a slurry type polymerization with Ziegler–Natta catalysts. Under the reaction conditions used decene contents remained at the 2 wt% level in ethylene/decene-1 copolymers. When additionally butene-1 was present in the polymerization, decene-1 contents were significantly higher. A synergistic effect was identified in the reactivities of butene-1 and decene-1 in terpolymerization with ethylene. The comonomer reactions were determined and comonomer contents measured by ¹³C-NMR spectroscopy. Decene-1 content had an effect on the polymer density and crystallinity, but virtually no effect on melting temperature. With high comonomer contents an additional melting range was identified in DSC curves at about 100°C.     

Modeling and Simulation of High Pressure Water Mist Systems

This paper describes work done to improve and validate the capability of fire dynamics simulator (FDS) to predict the dynamics of water mist sprays. Three single orifice and five multi-orifice spray heads are modeled with FDS based on information on the flow-rate, spray angle, operating pressure and experimentally determined particle size distribution. The capability of FDS to predict the drop size, velocity, mist flux and number concentration profiles within the spray cone is assessed. The effects of turbulence modeling on the predictions of the spray dynamics is investigated. The capability of FDS to predict the air entrainment by high-speed water sprays is validated using experiments in rectangular channels with open ends.     

Will New Antenna Materials Enable Single Path Multiple Access (SPMA)?

The aim of this paper is to introduce a novel frequency reuse concept especially for macro cellular networks to substantially increase the mobile network capacity, and simultaneously to avoid the implementation of low efficient small cells. Single path multiple access (SPMA) utilizes the characteristics of independent propagation paths for particular geographical location in the coverage area of mobile network. The proposed concept is based on the assumption that new approach will be adopted by the antenna manufacturers for producing advanced antennas by utilizing materials like metamaterials including carbon based nanotechnology, and graphene. In SPMA concept, communication between base station and mobile station happens through only single independent propagation path, and frequency resources can be reused in 5 m  \(\times \)  5 m areas or even more often in 1 m  \(\times \)  1 m areas, but limited by a base station/mobile station antenna requirement. Thus, the capacity of the network will be increased dramatically, and it can be managed in centralized manner at certain macro site locations. In already deployed cellular networks, these macro sites are mostly easily available, and that would help to implement SPMA to enhance the network capacity. Simulation results provided in this paper show the applicability of SPMA technique, by limiting the radiation of signal as single path propagation between base station and mobile station.     

Light transmission model for determination of the refractive index of solid particles in suspensions: an immersion study

We report on a model to determine the light transmission of solid particles in immersion liquids. Using the model, optical and physical properties of suspensions such as the refractive index of the particles can be retrieved. The model can also be used in the case of colored suspensions, where the detection of only the maximum transmission would give an inaccurate refractive index for a particle. The validity of the method was tested with CaF(2) particles. Potential applications include scientific studies of the optical properties of micro- and nanoparticles or microorganisms in a liquid matrix. The model is also useful in industry where monitoring of suspensions and colloids is an issue.