An intercomparison of bio-optical techniques for detecting dominant phytoplankton size class from satellite remote sensing

Satellite remote sensing of ocean colour is the only method currently available for synoptically measuring wide-area properties of ocean ecosystems, such as phytoplankton chlorophyll biomass. Recently, a variety of bio-optical and ecological methods have been established that use satellite data to identify and differentiate between either phytoplankton functional types (PFTs) or phytoplankton size classes (PSCs). In this study, several of these techniques were evaluated against in situ observations to determine their ability to detect dominant phytoplankton size classes (micro-, nano- and picoplankton). The techniques are applied to a 10-year ocean-colour data series from the SeaWiFS satellite sensor and compared with in situ data (6504 samples) from a variety of locations in the global ocean. Results show that spectral-response, ecological and abundance-based approaches can all perform with similar accuracy. Detection of microplankton and picoplankton were generally better than detection of nanoplankton. Abundance-based approaches were shown to provide better spatial retrieval of PSCs. Individual model performance varied according to PSC, input satellite data sources and in situ validation data types. Uncertainty in the comparison procedure and data sources was considered. Improved availability of in situ observations would aid ongoing research in this field.     

Public-Private Partnerships in the Water Sector

Abstract

Types of partnerships between public and private companies in water and sewage services are evaluated on the basis of the economic efficiency of the scheme for each partner. Modeling of public-private partnerships involves the formulation of a contract prototype, which determines the roles, functions, and responsibilities as well as the allocation of costs and revenues for each partner. Alternative water management scenarios are used to identify the investments required for meeting the projected demand for water and sewage services. Investment and operational costs as well as revenues from water and sewage services are estimated according to the allocation defined in the contract prototype. The economic efficiency of the scheme is assessed through a cost benefit analysis for each partner. The evaluation of different water management scenarios indicates that, for the Cyclades Islands, Greece, there is a substantial water market where several forms of partnerships could be attractive for both the public and the private sectors. Such partnerships include, among others, lease purchase, temporary privatization, built operate transfer (BOT), and built own operate transfer (BOOT). These forms of public-private partnerships could also be successful in similar regions where significant improvements and expansion of the infrastructure is required while access to the required funds and expertise is restricted for small public water companies.     

Direction-based adaptive data propagation for heterogeneous sensor mobility

We consider sensor networks where the sensor nodes are attached on entities that move in a highly dynamic, heterogeneous manner. To capture this mobility diversity we introduce a new network parameter, the direction-aware mobility level, which measures how fast and close each mobile node is expected to get to the data destination (the sink). We then provide local, distributed data dissemination protocols that adaptively exploit the node mobility to improve performance. In particular, “high” mobility is used as a low cost replacement for data dissemination (due to the ferrying of data), while in the case of “low” mobility either (a) data propagation redundancy is increased (when highly mobile neighbors exist) or (b) long-distance data transmissions are used (when the entire neighborhood is of low mobility) to accelerate data dissemination toward the sink. An extensive performance comparison to relevant methods from the state of the art demonstrates significant improvements, i.e. latency is reduced by even four times while keeping energy dissipation and delivery success at very satisfactory levels.     

The potential of WHR/batch and cullet preheating for energy efficiency in the EU ETS glass industry and the related energy incentives

The European Emissions Trading Scheme (EU ETS) covers approximately 45% of European greenhouse gases (GHGs), 11,000 stationary installations as well as aircraft operators. The EU ETS particularly affects the energy-intensive industries while it imposes a significant risk of “carbon leakage,” i.e., the risk of EU industry departing to countries with weaker restraints on GHG emissions. The EU glass industry, being capital intensive and also requiring long investment cycles, is the world’s largest glass producer with a market share close to one third of global production. Therefore, it is of significant importance to view the position of the EU ETS glass industry in terms of energy conservation possibilities. The present paper utilizes a vertical approach to provide information on both ETS market evolution and specific technical information to support technological innovation to the glass industry. EU ETS glass industry is analyzed regarding the balance between allocated European Union emission allowances (EUAs), verified CO₂ emissions, and potential shortfall in allowances so as to determine the situation of glass industries and the extent of urge for energy-saving activities towards the strengthening of their position within the requirements of the EU ETS phase III. The replication potential of waste heat recovery (WHR) through batch preheating is specifically addressed since it is considered a promising technology according to the latest Best Available Techniques (BAT) reference document for the glass industry under Directive IED 2010/75/EU. A case study for a container glass furnace based on simulation results is presented investigating the impact of different operating and design configurations on specific energy consumption and CO₂ emissions.     

A study on natural clinoptilolite for CO2/N2 gas separation

Based on its low cost and low water adsorption capacity, compared to synthetic zeolites (A-type, X-type and Y-type), natural, untreated clinoptilolite was examined as a potential adsorbent for a separation process targeting on removal of CO₂ from flue gas. Taking into consideration typical flue gas composition and temperature, adsorptive properties of binary CO₂/N₂ mixtures were tested in the temperature range of 268 to 403 K and compared with literature data. The results showed that CO₂ concentration, total pressure, and temperature strongly affect selectivity and working capacity, restricting the conditions under which the material could be used as an efficient adsorbent.     

Microstructure characterization and photocatalytic activity of mesoporous TiO2 films with ultrafine anatase nanocrystallites

A series of mesoporous TiO₂ films on borosilicate glass with ultrafine anatase nanocrystallites were successfully synthesized using a non-acidic sol gel preparation route, which involves the use of nonionic surfactant Tween 20 as template through a self assembly pathway. The microstructure of these TiO₂ films was characterized by XRD, SEM, HR-TEM, UV-Vis spectroscopy, and N₂ adsorption-desorption isotherm analysis. Their photocatalytic activities were investigated by using creatinine as a model organic contaminate in water. It was found that all mesoporous TiO₂ films prepared with Tween 20 exhibited a partially ordered mesoporous structure. The photocatalytic activity of the TiO₂ films could be remarkably improved by increasing Tween 20 loading in the sol at the range of 50% (v/v), which yielded large amount of catalyst (anatase) on the glass support and enhanced specific surface area. The optimum Tween 20 loading was 50% (v/v) in the sol, above which good adhesion between TiO₂ films and borosilicate glass could not be maintained. The final TiO₂ film (Tween 20: final sol = 50%,v/v) exhibits high BET surface area (∼ 120 m²/g) and pore volume (0.1554 cm³/g), ultrafine anatase nanocrystallinity (7 nm), uniform and crack free surface morphology, and improved photocatalytic activity.     

The path towards healthier societies,environments, and economies: a broader perspective for sustainable engineered nanomaterials

Clean Technologies and Environmental Policy - Economic value is no longer adequate by itself as a proxy for the value-added benefits (VAB) assumed to be generated by emerging technologies such as...     

Lung fixation by perfusion--a simple method to control the pressure in the perfusion circuit

A simple method which maintains the hydraulic pressure at a constant level during fixation of organs by perfusion is described. This is obtained by means of a glass tube interposed between a peristaltic pump and the organ to be perfused, the specially designed glass tube acting as a safety valve. The efficiency of the system is tested by electromagnetic pressure recording.     

Water supply management approaches using US on the island of Rhodes, Greece

Desalination powered by renewable energy sources (RES) is presented as an alternative option for the water supply augmentation in the semi-arid region of the island of Rhodes. The case study was chosen as the island relies mostly on the exploitation of groundwater resources and faces serious water shortage problems in an already stressed environment. Alternatives are discussed and compared in contrast to the construction of storage dams to meet urban water needs up to the year 2040. Results may indicate that through the use of financial incentives coupled with holistic water management approaches, desalination powered by RES could be an attractive and environmentally friendly option in an effort to solve problems related to water quantity and quality in semi-arid regions with adequate renewable energy potential.