Gas turbine prime movers fuelled by LNG as a future alternative for sustainable power in marine propulsion: current emission policy assessment and exhaust quality evaluation

In recent years, climate change has dramatically shown its effects in terms of fluctuations of temperatures because of increased global warming due to greenhouse gas emissions. Pollution control is strongly linked to atmospheric acidification and contaminants in combustion exhausts. In such a contest, marine propulsion is actually a key player that is accounting for a substantial contribution to pollution. Kyoto protocol’s obligations established decarbonisation as a compulsory commitment and contaminant constraints are defined by current emission policy and regulations both on a global and on a regional basis. In this paper, a study is carried out in order to develop a framework for current emission policy and assessment of exhausts due to constraints imposed on fuel choice. Gas fuelled marine propulsion, implemented through state-of-the-art GT areoderivative prime movers, powered by LNG, is analysed from the environmental point of view. The pollutant emissions from various size GT models are evaluated through both GT datasheets and commercial (as well as self-coded) software, in order to assess the validity of LNG as an alternative fuel option for future sustainable marine applications

Feasibility of mini combined cycles for naval applications

The objective of energy production with low environmental impact will have, in the near future, high potential of development also for naval applications. The containment of pollutant emissions can be achieved by the combined use of an innovative mini gas-steam combined cycle with thermal energy cogeneration to feed the ship thermal utilities, in place of the current Diesel engine application, and liquefied natural gas as fuel (LNG). The present work is focused on the definition of the architecture of the plant, by selecting optimal distribution of pressure and temperature and repartition of power between Gas Turbine (GT), Steam Turbine (ST) and thermal utilities, as well as on the choice and sizing of the individual components. The main purpose is the definition of a compact, high efficiency, system. The proposed basic mini-cycle ranges from 2 MW to 10 MW electric power. Thanks to the combined heat and power cogeneration plant adopted, for an overall electrical efficiency of about 30%, a total return (thermal + electricity) of about 75% can be achieved. An example of plant providing large power, in a partially modular arrangement is also proposed

High specificity of cphA-encoded metallo-β-lactamase from Aeromonas hydrophila AEO36 for carbapenems and its contribution to β-lactam resistance

The Aeromonas hydrophila AE036 chromosome contains a cphA gene encoding a metallo-beta-lactamase highly active against carbapenem antibiotics. This enzyme was induced in strain AE036 to the same extent by both benzylpenicillin and imipenem. When the cphA gene was inserted into plasmid pACYC184, used to transform Escherichia coli DH5 alpha, the MICs of imipenem, meropenem, and penem HRE664 for recombinant clone DH5 alpha(pAA20R), expressing the Aeromonas metallo-beta-lactamase, were significantly increased, but those of penicillins and cephalosporins were not. When the metallo-beta-lactamase purified from E. coli DH5 alpha(pAA20R) was assayed with several beta-lactam substrates, it hydrolyzed carbapenems but not penicillins or cephalosporins efficiently. These results demonstrate that this metallo-beta-lactamase possesses an unusual spectrum of activity compared with all the other class B enzymes identified so far, being active on penems and carbapenems only. This enzyme may thus contribute to the development of resistance to penems and carbapenems but not other beta-lactams

Molecular and supramolecular chirality: R2PI spectroscopy as a tool for the gas-phase recognition of chiral systems of biological interest.

A review. In life sciences, diastereomeric chiral mol./chiral receptor complexes are held together by a different combination of intermol. forces and are therefore endowed with different stability and reactivity. Detn. of these forces, which are normally affected in the condensed phase by solvent and supramol. interactions, can be accomplished through the generation of diastereomeric complexes in the isolated state and their spectroscopic investigation. This review presents a detailed discussion of the mass resolved Resonant Two Photon Ionization (R2PI-TOF) technique in supersonic beams and introduces an overview of various other technologies currently available for the spectroscopic study of gas phase chiral mols. and supramol. systems. It reports case studies primarily from the authors' recent work using R2PI-TOF methodol. for chiral recognition in clusters contg. mols. of biol. interest. The measurement of absorption spectra, ionization and fragmentation thresholds of diastereomeric clusters by this technique allow the detn. of the nature of the intrinsic interactions, which control their formation and which affect their stability and reactivity

Formation mechanisms and phase stability of solid-state grown cspbi3 perovskites

CsPbI3 inorganic perovskite is synthesized by a solvent-free, solid-state reaction, and its structural and optical properties can be deeply investigated using a multi-technique approach. X-ray Diffraction (XRD) and Raman measurements, optical absorption, steady-time and time-resolved luminescence, as well as High-Resolution Transmission Electron Microscopy (HRTEM) imaging, were exploited to understand phase evolution as a function of synthesis time length. Nanoparticles with multiple, well-defined crystalline domains of different crystalline phases were observed, usually surrounded by a thin, amorphous/out-of-axis shell. By increasing the synthesis time length, in addition to the pure α phase, which was rapidly converted into the δ phase at room temperature, a secondary phase, Cs4PbI6, was observed, together with the 715 nm-emitting γ phase

Solvent free interactions in contact pairs of molecules of biological interest: Laser spectroscopic and electrospray mass spectrometric studies

A laser spectroscopic and mass spectrometric study of ionic and molecular clusters of biological interest is reported. The molecules of interest and their aggregates were generated in a supersonic beam and analyzed by mass resolved resonant two photon absorption and ionization (R2PI) and by collision induced mass spectrometry (CID-MS). The absence of the solvent allows to study these systems in the isolated state free of undesired solvent effects which may level off the differences in their properties. The gas phase results have been compared to theoretical estimates of the structure and stability of the systems under investigation

Raman spectra and vibrational analysis of CsPbI3: a fast and reliable technique to identify lead halide perovskite polymorphs

A major issue in the development of Lead halide perovskites is the assessment of the crystal structure of the samples, due to their typically limited time-stability, and the understanding of the role of external factors that can induce a crystal phase transformation (such as humidity, intense light flux, temperature, etc.). In this perspective, it is of utmost importance to have at disposal a fast and reliable experimental tool able to give an immediate indication of the polymorph of the sample with the possibility to integrate in-situ measurements for constant monitoring. In this paper we propose Raman spectroscopy as the ideal technique to solve this problem. The vibrational analysis of CsPbI3 in the α-phase and δ-phase and of the Cs4PbI6 secondary phase is reported and all the vibrational modes are assigned by comparing experimental spectra of the phases to Raman modes calculated within the DFT framework. Finally, the mechanism of laser induced phase degradation was studied using in-situ Raman measurements providing new insights on the secondary phase generated during the process

Association of single nucleotide polymorphisms with renal cell carcinoma in Algerian population

Background: Renal cell carcinoma (RCC) is a common malignant tumor of the urinary system. The etiology of RCC is a complex interaction between environmental and multigenetic factors. Genome-wide association studies have iden? tifed new susceptibility risk loci for RCC. We examined associations of genetic variants of genes that are involved in metabolism, DNA repair and oncogenes with renal cancer risk. A total of 14 single nucleotide polymorphisms (SNPs) in 11 genes (VEGF, VHL, ATM, FAF1, LRRIQ4, RHOBTB2, OBFC1, DPF3, ALDH9A1 and EPAS1) were examined. Methods: The current case?control study included 87 RCC patients and 114 controls matched for age, gender and ethnic origin. The 14 tag-SNPs were genotyped by Sequenom MassARRAY? iPLEX using blood genomic DNA. Results: Genotype CG and allele G of ATM rs1800057 were signifcantly associated with RCC susceptibility (p=0.043; OR=8.47; CI=1.00?71.76). Meanwhile, we found that genotype AA of rs67311347 polymorphism could increase the risk of RCC (p=0.03; OR=2.95; IC=1.10?7.89). While, genotype TT and T allele of ALDH9A1 rs3845536 were observed to approach signifcance for a protective role against RCC (p=0.007; OR=0.26; CI=0.09?0.70). Conclusion: Our results indicate that ATM rs1800057 may have an efect on the risk of RCC, and suggest that ALDH9A1 was a protective factor against RCC in Algerian populatio

Production of clusters and thin films of nitrides, oxides and carbides by pulsed laser ablation and deposition

A short introduction on the principles of laser-matter interaction, material evaporation, plume formation, its reactivity with suitable gases and finally deposition are here illustrated. Experiments by mass spectrometry of formation of clusters, precursors of thin films and nanoparticles of oxides, nitrides and carbides by pulsed laser ablation (PLA) are reported. Pulsed laser ablation of targets combined with an intense atomic source produced by radiofrequency (RF), are discussed in terms of generating chemical reactions or supplying the loss of volatile components