Renewable energy sources (RES) projects and their barriers on a regional scale: The case study of wind parks in the Dodecanese islands, Greece

The increasing energy challenges faced, in particular, by isolated communities, such as insular communities, call for an integrated, flexible and easy-to-apply methodology aiming at providing a list of renewable energy sources) (RES) projects capable to reduce green house gas (GHG) emissions, satisfy future energy forecasts and reach the objectives of international/national energy directives and obligations, as, for example, the ones set by the Kyoto Protocol by 2010. The EU project EMERGENCE 2010 developed such a methodology that is implemented here in the case study of wind parks in the Dodecanese islands in Greece. The results obtained consist of a final list of financially viable RES wind projects, for which various barriers have been previously identified and assessed. The additional advantages of the proposed methodology is that besides providing as an end result a comprehensive list of RES projects adopted to specific criteria and regional priorities, it also allows space for involving – from early stages – the local community and stakeholders in the decision-making process (participatory planning); in this way, the EMERGENCE 2010 methodology may assist towards the RES promotion and public acceptance, the profitability of RES investments and the regional sustainable development.     

The influence of alteration on the engineering properties of dolerites: The examples from the Pindos and Vourinos ophiolites (northern Greece)

The influence of alteration on the physico-mechanical properties of dolerites from the Pindos and Vourinos ophiolites, northern Greece, is investigated. Quantitative petrographic analysis shows that the samples display various percentages of secondary minerals. Two new micropetrographic indices are calculated from the results of petrographic modal analysis for the engineering assessment of dolerites: the micropetrographic strength index I_ps and the replacement index I_rep. The samples are also tested to determine water absorption, apparent density, total porosity, sand equivalent, uniaxial compressive strength, Los Angeles abrasion value, aggregate impact value, aggregate abrasion value and polished stone value. The influence of alteration on the rock quality and especially the relationships between the proposed micropetrographic indices and the engineering parameters are determined using regression analysis and the derived equations were verified by the t-test and the F-test. The relationships between the I_ps and I_rep indices and the engineering properties show that alteration products generally result in mechanically weaker rocks. However, the results of the physico-mechanical tests indicate that dolerites retain their strength and durability due to the low proportions of soft minerals and microcracks, along with the preservation of their igneous textures. The polishing resistance is the only engineering parameter that is positively affected by alteration processes, as expressed by the I_ps index. Particularly, the replacement of the primary mafic minerals by secondary minerals, expressed by the I_rep index, can enhance the polishing resistance of dolerites when used in the wearing surface of a road. The results also indicate strong positive correlations between the chlorite content and the water absorption and total porosity values.     

Saliva Proteomics as Fluid Signature of Inflammatory and Immune-Mediated Skin Diseases

Saliva is easy to access, non-invasive and a useful source of information useful for the diagnosis of serval inflammatory and immune-mediated diseases. Following the advent of genomic technologies and -omic research, studies based on saliva testing have rapidly increased and human salivary proteome has been partially characterized. As a proteomic protocol to analyze the whole saliva proteome is not currently available, the most common aim of the proteomic analysis is to discriminate between physiological and pathological conditions. The salivary proteome has been initially investigated in several diseases: oral squamous cell carcinoma and oral leukoplakia, chronic graft-versus-host disease, and Sjögren’s syndrome. Otherwise, salivary proteomics studies in the dermatological field are still in the initial phase, thus the aim of this review is to collect the best research evidence on the role of saliva proteomics analysis in immune-mediated skin diseases to understand the direction of research in this field. The results of PRISMA analysis reported herein suggest that human saliva analysis could provide significant data for the diagnosis and prognosis of several immune-mediated and inflammatory skin diseases in the next future.     

Reconstruction of large-scale flow structures in a stirred tank from limited sensor data

We combine reduced order modeling and system identification to reconstruct the temporal evolution of large-scale vortical structures behind the blades of a Rushton impeller. We performed direct numerical simulations at Reynolds number 600 and employed proper orthogonal decomposition (POD) to extract the dominant modes and their temporal coefficients. We then applied the identification algorithm, N4SID, to construct an estimator that captures the relation between the velocity signals at sensor points (input) and the POD coefficients (output). We show that the first pair of modes can be very well reconstructed using the velocity time signal from even a single sensor point. A larger number of points improves accuracy and robustness and also leads to better reconstruction for the second pair of POD modes. Application of the estimator derived at Re = 600 to the flows at Re = 500 and 700 shows that it is robust with respect to changes in operating conditions.     

KLE-(V)AR: A new identification technique for reduced order disturbance models with application to sheet forming processes

A new identification technique that combines the Karhunen–Loève expansion (KLE) with the use of Vector AutoRegressive processes (VAR) is presented in this paper. Given measurements, collected over a period of time, of a set of correlated random variables the method generates a reduced order state-space dynamic model describing the spatial and temporal relationship among the variables. Some of the advantages of the new method are the fewer number of parameters needed to be estimated compared with traditional subspace methods, and its ability to efficiently track nonstationary random processes. Simulation examples from high dimensional sheet forming processes are included for illustration.     

A novel solar collector

In recent years there has been considerable interest in solar energy utilization through bioconversion, and a promising application involves the mass culture of unicellular algae. The purpose of this study has been to develop systematic procedures for predicting the yield of such cultures as a function of geographic location and diurnal and seasonal conditions. The procedures allow for the use of available insolation data and account for both the spectral and directional characteristics of the incident radiation. Calculations for the maximum hourly production of algae and oxygen have been performed for the Indianapolis, Indiana region, and the results are in reasonable agreement with field data obtained at similar latitudes.     

The reaction coefficient of an enclosure to the solar energy collection

A dimensionless reaction coefficient R_a is defined which gives a measure of the solar energy collectivity of a room with opaque external walls. This number is defined as the ratio between the absorbed solar energy by the wall and the correspondent thermal gain of the room, and depends on the thermal and structural characteristics of the room and its environment. The reaction coefficient R_a is reduced to a simple expression and provides a simple way of estimating the amount of the net radiation energy gain by the room, when the amount of radiation, which is falling or absorbed by the wall, is given. This analytical relation has been confirmed experimentally especially with respect to the influence of the wall total thermal conductance on the reaction coefficient R_a.     

A hybrid CFD—reaction engineering framework for multiphase reactor modelling: basic concept and application to bubble column reactors

The coupling of turbulent mixing and chemical phenomena lies at the heart of multiphase reaction engineering, but direct CFD approaches are usually confronted with excessive computational demands. In this hybrid approach, the quantification of mixing is accomplished through averaging the flow and concentration profiles resulting from a CFD flow field calculation and a computational (“virtual”) tracer experiment. Based on these results, we construct a mapping of the CFD grid into a generalised compartmental model where the chemistry calculations can be efficiently carried out. In contrast to the empirical models used in the residence time distribution (RTD) approach, the compartmental model in this methodology, owning to its CFD origins, retains the essential features of the equipment geometry and flow field. A procedure for extracting the mixing information from k-ε based CFD codes is outlined, but the main concept of the approach is not restricted to any particular type of turbulence modelling, and will therefore benefit from future developments. A phenomenological model of mass transfer and chemical reaction, based on the penetration theory, is employed to simulate the interfacial phenomena in gas-liquid reactors, and a study of CO₂ absorption into alkali solution is presented to demonstrate the method.     

Correlations between petrographic and geometrical properties of ophiolitic aggregates from Greece

The study investigated the influence of petrographic characteristics on the geometrical properties of ultrabasic and basic ophiolitic aggregates from Greece. Quantitative petrographic analysis indicates that the studied lithologies display various percentages of secondary mineral phases. Statistical analyses indicate that the geometrical characteristics of ultrabasic rocks tend to improve as the micropetrographic index I _rep , the degree of serpentinisation, the ratio of soft to hard minerals and the ratio of secondary to primary minerals decrease. The aggregate particles of the basic lithotypes tend to be more elongated and flaky when the ratio of soft to hard minerals increases. The higher flakiness and elongation index values of the ultrabasic samples are attributed to the high percentage of serpentine, the local preferred orientation of the olivine grains and the existence of oriented transgranular microcracks.