Abstract
Ti-based materials are widely employed for several biomedical applications, including artificial prostheses . In fact these materials present high mechanical strength, low elasticity modulus, elevated corrosion resistance and excellent biocompatibility. The latter originates from the very low metal release and toxicity of corrosion products of Ti, Zr, Nb, Ta and Mo, at variance with stainless steels and Co-Cr alloys. Ti-Mo cast alloys with different compositions were melted in an arc furnace with a non-consumable W electrode and a water-cooled copper hearth under ultra-pure argon atmosphere. Alloys were passivated in acidic or neutral aqueous solutions by linear potential sweep, up to different potentials. Upon anodizing, barrier-type oxide films were formed on the alloys surface, showing interference colours depending on their thickness. The kinetics of film growth was influenced by Mo content in the alloy; formation efficiency was lower in acidic solution than in neutral ones, likely due to Mo partial dissolution. Passive films were investigated by photoelectrochemical and impedance experiments. It was found that behaviour of the films changed with their thickness and with Mo content in the metallic alloy. For low Mo contents in the alloy films show always semiconducting behaviour, irrespective of thickness, in agreement with the behaviour of Ti oxide films. For higher Mo contents behaviour changes from semiconducting to insulating with increasing thickness. Moreover, EIS experiments show that, at corresponding thickness, films become more resistive with increasing Mo content in the alloys. XPS analysis confirms the presence of Mo into passive films. Results can be interpreted assuming the formation of mixed Ti-Mo oxide films, where MoO3 groups partially compensate oxygen deficiencies of TiO2.

Abstract
Recent advances in polymer electrolyte fuel cells technology demand operation at high working temperatures to improve efficiency, tolerance of contaminants and for an easy water management. High temperature operation influences significantly carbon black corrosion, platinum dissolution and sintering . The scope of this work is to evaluate the high temperature performance and stability of the catalysts in the presence of perfluorosulphonic membranes and to correlate these properties with the physico- chemical characteristics both in terms of electro-catalytic activity for oxygen reduction and resistance to degradation under fuel cell conditions. We have overcome the constraints related to the dehydration behaviour of the membrane at high temperature by pressurizing the PEM single cell and operating the humidifiers at the same temperature and pressure of the cell . Although, the operating conditions do not exactly reproduce those aimed by the automakers, i.e. ambient pressure and 25% relative humidity (RH), the present approach may provide a basis to identify the high temperature degradation mechanism for conventional PEMFCs and alleviate through proper preparation procedures the performance loss. An investigation of carbon- supported Pt/C and PtCo/C catalysts was carried out with the aim to evaluate their stability under high temperature polymer electrolyte membrane fuel cell (PEMFC) operation. Carbon-supported nanosized Pt and PtCo particles with a mean particle size between 1.5 nm and 3 nm were prepared by using a colloidal route. A suitable degree of alloying was obtained for the PtCo catalyst by using a carbothermal reduction. The catalyst stability was investigated to understand the influence of carbon black corrosion, platinum dissolution and sintering in gas-fed sulphuric acid electrolyte half- cell at 75 ?C and in PEMFC at 130 ?C. Electrochemical active surface area and catalyst performance were determined in PEMFC at 80 ?C and 130 ?C. A maximum power density of about 700 mWcm-2 at 130 ?C and 3 bar abs. O2 pressure with 0.3 mg Pt cm-2 loading was achieved. The PtCo alloy showed a better stability than Pt in sulphuric acid after cycling; yet, the PtCo/C catalyst showed a degradation after the carbon corrosion test. The PtCo/C catalyst showed smaller sintering effects than Pt/C after accelerated degradation tests in PEMFC at 130 ?C. The results have been interpreted in terms of structural and surface properties of the catalysts.

Abstract
White mussels (Donax serra) are widely distributed from northern Namibia to the Eastern Cape of South Africa and are harvested along sandy beaches in the intertidal zone, and mainly during spring low tides. They are harvested by the broader recreational sector along the entire extent of their distribution range as part of a general bait permit, but the commercial sector is restricted to the west coast on the basis of abundance. The high abundance in this region is linked to higher plankton production, compared to the rest of the South African coast. In 2006, a new term of 2-year rights, which is extended by another two years, was allocated in this sector, still restricted to the west coast and for bait purposes only. In the past, each right holder was limited to a monthly catch of 2000 mussels, however since October 2006, the monthly catch limit was lifted, with the aim of improving the quality of catch and effort data for future use in resource assessments. A minimum legal size of 35mm is applied for both the commercial and recreational sectors. Harvesting of white mussels is retained as a developing fishing sector and limited to seven areas along the west coast. Each of the seven right holders are allocated one of seven commercial fishing areas along the west coast from the area north of the border of Koeberg Power Station at Bokpunt, up to Oliphants River mouth in Lamberts Bay. Preliminary results show substantially varying numbers of mussel abundance across the different areas sampled. This ARTICLE describes briefly the history of this fishery, processes involved in the establishment of this fishery, as well as preliminary results and the proposed way forward.

Abstract
Nitrates and other nitrogen-containing compounds are harmful to the environment and pose a particular risk when they become concentrated in drinking water. Consequently, there is an ever-increasing interest in developing reliable, fast and simple sensors to detect low concentrations of nitrate and in developing new environmental technologies to effectively remove nitrates and convert them into harmless products. In particular, modified electrochemical sensors are playing an increasingly important role in environmental monitoring and are the focus of intense research in the effort to develop new and improved techniques. Electrodes modified with nanosized noble metal particles have attracted considerable interest due to their unique physicochemical properties. Electrochemistry offers a method for size-controlled synthesis of nanoparticles by simply adjusting electrolysis parameters. In addition, it allows for the particles to be directly adsorbed onto a surface, ready for immediate use as a sensor. In this paper, we show how to simply prepare silver nanoparticles via various electrochemical methods. First, colloidal silver was formed potentiostatically under the protection of the stabilising agent, poly(N-vinylpyrrolidone) . Like most methods for synthesising nanoparticles electrochemically, these are prepared by chemical reduction of the metal salt, in this case silver nitrate (AgNO3). The stabilising agent immediately coats the particles and therefore prevents agglomeration. These particles were analysized-using UV-Visible spectroscopy, which is a very accurate and simple tool to measure the size of the nanoparticles. Silver nanoparticles show a strong absorption band at approximately 420 nm. Next we show how silver is directly deposited on a glassy carbon electrode via a potentiostatic single-pulse technique . Again it involves the reduction of the metal salt, this time at the electrode surface, for only a few seconds. The longer the deposition time the larger the particles. We investigated this electrodes sensitivity to nitrate using cyclic voltammetry. The electrochemical reduction of nitrate shows two signals, with peak potentials at approximately -1.3 V and -1.6 V. A detection limit of 5x10-5 M KNO3 was reached.

Abstract
Nitro derivatives of quinoline have been proven to be genotoxic, thus their presence in environmental samples is a legitimate cause for concern. Electrochemical detection using advanced electrode materials in batch and flow analysis offers sensitive and relatively selective tool for their determination. In this contribution, it will be demonstrated on the example of 5- and 6-nitroquinoline (5-NQ, 6-NQ). For their determination direct current voltammetry (DCV) and differential pulse voltammetry (DPV) at nontoxic mercury meniscus modified silver solid amalgam electrode (m-AgSAE) were used. Linear calibration curves in the concentration range of 4-10"6 - M0-4 mol L-1 were obtained. Further, the polished silver solid amalgam electrode (p-AgSAE) was employed for amperometric detection of 5-NQ in flow injection analysis (FIA). Under optimized conditions (mobile phase 0.05 mol L-1 borate buffer, pH 9.0; flow rate 4 mL min-1, detection potential -1.6 V; injection volume 100 |iL) the limit of quantitation of ~ 4-10-6 mol L-1 was achieved. The repeatability of the detector response is satisfactory (RSD ~ 1.3 % for c(5- NQ) = 1 ? 10-4 mol L-1). Practical applicability of the method was verified for the determination of micromolar concentrations of 5-NQ in drinking and river water model samples.

Abstract
Chlorinated aliphatic hydrocarbons, such as 1,2-dichloroethane (EDC), are frequently found in many surface and ground waters, as a result of their widespread use in industry and in various household products and their poor biodegradability. Presently, 1,2-dichloroethane belongs to those chemicals with the highest production rates. Average annual growth rates higher than 10 % were achieved during the past 20 years. Although these growth rates declined during the past several years, in the long run 1,2- dichloroethane is expected to maintain its leading position among the chlorinated organic chemicals . EDC is one of the more toxic common chlorinated substances . It can cause depression of the central nervous system, mental confusion, dizziness, nausea, and vomiting. EDC is present on the US Environmental Protection Agency priority list of pollutants with a limit of 0.005 mg l-1 in drinking water while a limit of 0.003 mg l-1 has been fixed by European Community. Both destructive and non-destructive methods have been used to remove dichloroethane and other chlorinated aliphatic hydrocarbons. Destructive methods include aerobic/anaerobic degradation , chemical reaction via zero-valent iron , chemical and photochemical oxidation [4-5], electrochemical reduction [6-9] and oxidation [10,11]. In the present work, the electrochemical treatment of water solutions containing dichloroethane was performed by both electrochemical reductive and oxidation processes.