Biomass as an energy source: thermodynamic constraints on the performance of the conversion process

In the present work an equilibrium model (gas-solid), based on the minimization of the Gibbs energy, has been used in order to estimate the theoretical yield and the equilibrium composition of the reaction products (syngas and char) of biomass thermochemical conversion processes (pyrolysis and gasification). The data obtained from this model have also been used to calculate the heating value of the fuel gas, in order to evaluate the overall energy efficiency of the thermal conversion stage. The proposed model has been applied both to partial oxidation and steam gasification processes with varying air to biomass (ER) and steam to carbon (SC) ratio values and using different feedstocks; the obtained results have been compared with experimental data and with other model predictions obtaining a satisfactory agreement.

Experimental determination of average turbulent heat transfer and friction factor in stator internal rib-roughened cooling channels

In gas turbine cooling design, techniques for heat extraction from the surfaces exposed to the hot stream are based on the increase of the inner heat transfer areas and on the promotion of the turbulence of the cooling flow. This is currently obtained by casting periodic ribs on one or more sides of the serpentine passages into the core of the blade. Fluid dynamic and thermal behaviour of the cooling flow have been extensively investigated by means of experimental facilities and many papers dealing with this subject have appeared in the latest years. The evaluation of the average value of the heat transfer coefficient most of the time is inferred from local measurements obtained by various experimental techniques. Moreover the great majority of these studies are not concerned with the overall average heat transfer coefficient for the combined ribs and region between them, but do focus just on one of them. This paper presents an attempt to collect information about the average Nusselt number inside a straight ribbed duct. Series of measurements have been performed in steady state eliminating the error sources inherently connected with transient methods. A low speed wind tunnel, operating in steady state flow, has been built to simulate the actual flow condition occurring in a rectilinear blade cooling channel. A straight square channel with 20 transverse ribs on two sides has been tested for Re of about 3 x 10(4), 4.5 x 10(4) and 6 x 10(4). The ribbed wall test section is electrically heated and the heat removed by a stationary flow of known thermal and fluid dynamic characteristics.

[Roberts-SC phocomelia syndrome]

Roberts syndrome and SC phocomelia syndrome represent two malformative syndromes that, considering the presence of many common characteristics, are actually treated as one pathological entity. These syndromes have a chromosomal abnormality in common resulting from an premature centromere splitting in prometaphase. A review of salient features and a case diagnosed in the neonatal period is reported.

[Findings on smoking habits in Valle dell'Agno. (U.L.S.S. no. 7 of the Veneto region)]

A study regarding te habit of smoking of the population of this area was accomplished by use of questionnaire completed by students of the local high schools. The study included 7279 subjects subdivided as follow: 1776 fathers, 1815 mothers and 3688 students/workers of age 12 years and older. Results regarding the parent group showed that 51,91% of the fathers and 21,65% of the mothers were smokers. Only the mother group showed a correlation of smoking with various levels of education and occupation. Results regarding the younger age groups revealed, in age range 12-14 years, a positive history of smoking in 8,12% of males and 7,61% of females; this incidence increased to 53,76% and 36,44% respectively by age 25 years. Occupation categories and smoking parents as an incentive element showed relationships with smoking. A progressively increasing incidence of smoking at an increasingly earlier age with greater involvement of females was shown in this study. However, the smoking incidence in our area is less than that in other areas of the Veneto probably because of local geographic and economic factors.

Sex-reversed XY females with campomelic dysplasia are H-Y negative

Three families with infants affected with campomelic dysplasia, a genetically determined mesenchymal disease frequently associated with sex reversal were studied. Two XY females with ovarian gonadal differentiation and typical clinical features of campomelic dysplasia could be tested for H-Y antigen and were found to be H-Y negative.