Biomass integrated gasification combined cycle with reduced CO2 emissions: Performance analysis and life cycle assessment (LCA)

Performance analysis and life cycle assessment (LCA) of an integrated gasification combined cycle (IGCC) fed with biomass with upstream CO₂ chemical absorption has been carried out. The main working conditions have been determined by mean of partial exergetic analysis. A sensitivity analysis with respect to the CO₂ absorbing solution composition has also been carried out. The reachable efficiency ranges between 35% and 36%, depending on gas turbine technology level. In comparison with efficiency values previously found for an IGCC fed with coal with upstream CO₂ chemical absorption (38–39%), the configuration studied seems to be attractive because of the possibility of operating with a simplified scheme (without H₂S removal process) and at atmospheric pressure and for the possibility of using biomass in a more efficient way with respect to conventional combustion systems. Due to the lower efficiency, the specific CO₂ emission results higher (170 kg/MW h) with respect to the cycle fed with coal and CO₂ removal (130 kg/MW h). Moreover, the CO₂ balance has been determined with respect to the entire life cycle of the plant, including the construction, operation, dismantling and the biomass growing phases.     

Carbon dioxide removal in power generation using membrane technology

Carbon dioxide separation by means of membranes from methane reformed synthesis gas and from semi-closed cycle flue gases has been studied. In the first case, removing carbon dioxide using membrane is more energy consuming than removing it, from the same synthesis gas, using chemical absorption, leading to overall energy conversion efficiency of about 39% for the recuperated-auto thermal reforming (R-ATR) cycle equipped with membrane vs. 45% for the same R-ATR equipped with chemical absorption. With reference to the semi-closed cycle, the net cycle efficiency in the case of membrane removal (42.7%) seems to be not very far from the chemical absorption case (46%). Finally, published data about CO₂ membrane separation specific cost have been analysed, showing that the membrane technology for flue gas application can be competitive with respect to chemical absorption if CO₂ flue gas concentration is higher than 10%.     

Effect of water content on thermal and dynamic mechanical properties of xanthan powder: A comparison between standard and novel techniques

In this work, the sorption isotherms of xanthan powder obtained under static and dynamic conditions and their fitting with mathematical models were discussed. The transitions within xanthan-water systems have been investigated using a standard material characterization technique - Differential Scanning Calorimetry (DSC) - and two novel techniques - Dynamic Mechanical Thermal Analysis (DMTA) material pocket and Phase Transition Analysis (PTA). It was found that within water-xanthan systems, the onset temperature for the melting of freezable water obtained from DSC method was in agreement with freezable water melting peaks obtained via DMTA material pocket at levels of hydration when the freezable water was present. Also, low-temperature transitions, related to polysaccharide-water interactions, were observed by both techniques within xanthan systems which contained no freezable water. However, the use of the PTA technique was limited to xanthan systems with low water content.     

Neonatal capsaicin exposure affects isolation-induced aggressive behavior and hypothalamic substance P levels of adult male mice (Mus musculus).

Subcutaneous (sc) administration of capsaicin (50 mg/kg) at Postnatal Days 2 and 5 exerted long-term effects on isolation-induced aggressive behavior of adult mice of the CD-1 strain. Isolated capsaicin-treated mice (scored during a 10-min session) showed the highest frequency and the longest duration of total attacks, attacks, rattling, and offensive upright posture when compared with nonisolated capsaicin-treated Ss and both isolated and nonisolated vehicle control animals. Hypothalamic substance P (SP) was assessed by radioimmunoassay. Capsaicin treatment significantly lowered hypothalamic SP content in both isolated and nonisolated mice. Moreover, individual scores of isolated capsaicin-treated Ss showed a significant correlation between SP depletion and expression of offensive upright posture. Isolation per se was revealed to play an important role in depleting SP from the hypothalamus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Helicobacter pylori detection by polymerase chain reaction in gastric juice and its correlation with the histology (Giemsa)]

HP infection is involved in the pathogenesis of several gastroduodenal diseases, as type B chronic gastritis, duodenal and gastric ulcer, MALT lymphoma and gastric cancer. The recent availability of molecular techniques, specifically the PCR, allow us to detect very low amounts of the bacterium. The aim of the study is to evaluate the presence of HP in gastric juice by PCR technique and to correlate this findings with histology (Giemsa) of gastric mucosa. Gastric juice PCR positive findings were found in 10/31 (32.3%) HP positive patients at histology. We concluded that HP in gastric juice is possible to detect by molecular techniques. In our study 32.3% of the patients showed the presence of HP in gastric juice.     

Photosynthetic production of Dunaliella biomass from natural salt water and carbon dioxide

A Dunaliella strain has been isolated and grown in a medium containing saline lake water. Using 40% saline water and mixture of CO₂-air (4% CO₂) the algae grew with a specific growth rate of 0.073 h⁻¹. The maximum cell concentration was 5.6 × 10⁷ cells cm⁻³ which corresponded to 3.63 g dm⁻³ of dry biomass. Using 80% saline water, a glycerol concentration of 1.47 g glycerol g⁻¹ of, protein was obtained which amounted to 44.3% of Dunaliella dry weight. Fermentor CO₂ from a continuous yeast culture was also used as carbon source for photosynthetic growth. At 2.5% CO₂ in the exit gas a decrease of the specific growth rate was observed but the final concentration attained was comparable to that obtained with CO₂-air mixtures.