New formulations for unsaturated polyester resins and their interactions with low-profile agents and glass fibres

Special anhydrides, such as hexahydrophthalic, methyl-hexahydrophthalic, nadic, methylnadic and methyl-tetrahydroxyphthalic, have been polycondensed with glycols such as propylene and di-propylene, to obtain new formulations for unsaturated polyesters. The properties of these resins, such as tensile behaviour and ultraviolet resistance, neat or mixed with anti-shrinkage additives have been examined and compared to standard polyester resins. Particular attention was paid to the study of the influence of low-profile agents on the resulting phase structures of cured systems. Moreover, the role played by the different phases on the fibre/matrix addition in composite materials reinforced with coated glass fibres was also investigated.     

Process simulation of a hybrid SOFC/mGT and enriched air/steam fluidized bed gasifier power plant

The aim of this work is to experimentally and numerically analyze the performance of a integrated power plant composed by a steam oxygen fluidized bed biomass gasifier fed by woods, a Solid Oxide Fuel Cell (SOFC) and a micro Gas Turbine (mGT). The numerical analysis is carried out by using ChemCAD software. In particular, SOFC and gasifier were modeled using proper developed Fortran subroutines interfaced to the basic software. The adopted SOFC model was already validated by the authors in previous works, while the gasifier model was here developed and validated by means of experimental activities carried out by using a bench scale gasifier. Different compounds (Benzene, Toluene, Naphthalene, Phenols) were chosen to analyze the tar evolution in the gaseous stream during the gasification process. Hot gas cleaning (based on catalytic ceramic filter candles inserted in the freeboard of the gasifier – UNIQUE concept) was adopted to remove tar and particulates from the fuel hot gas stream. Different moisture contents in the range between 10 and 30% (i.e. in a deviation of 10% around the usual wood moisture content of 20%) were numerically simulated as well as the degree of purity of the oxygen utilized in the power plant (between 25% and 95%, the rest being N₂). The power requirement for pure oxygen production leads to a reduction of the electrical efficiency of the whole power plant. For this reason, a sensitivity analysis was conducted to find the optimal operation conditions in order to maximise the syngas (H₂, CO) content in the produced gas, while maintaining a high overall electrical efficiency.     

Thermodynamic modeling of hydrogen refueling for heavy-duty fuel cell buses and comparison with aggregated real data

The foreseen uptake of hydrogen mobility is a fundamental step towards the decarbonization of the transport sector. Under such premises, both refueling infrastructure and vehicles should be deployed together with improved refueling protocols. Several studies focus on refueling the light-duty vehicles with 10 kg_H2 up to 700 bar, however less known effort is reported for refueling heavy-duty vehicles with 30–40 kg_H2 at 350 bar. The present study illustrates the application of a lumped model to a fuel cell bus tank-to-tank refueling event, tailored upon the real data acquired in the 3Emotion Project. The evolution of the main refueling quantities, such as pressure, temperature, and mass flow, are predicted dynamically throughout the refueling process, as a function of the operating parameters, within the safety limits imposed by SAE J2601/2 technical standard. The results show to refuel the vehicle tank from half to full capacity with an Average Pressure Ramp Rate (APRR) equal to 0.03 MPa/s are needed about 10 min. Furthermore, it is found that the effect of varying the initial vehicle tank pressure is more significant than changing the ambient temperature on the refueling performances. In conclusion, the analysis of the effect of different APRR, from 0.03 to 0.1 MPa/s, indicate that is possible to safely reduce the duration of half-to-full refueling by 62% increasing the APRR value from 0.03 to 0.08 MPa/s.     

Comparative study of diagnostic hysteroscopy and transvaginal ultrasonography in patients with abnormal uterine hemorrhage during the peri- and post-menopausal period

BACKGROUND: The aim of this study was to determine the diagnostic value of hysteroscopy and transvaginal ultrasonography in patients with abnormal uterine bleeding (AUB) in the peri and postmenopausal period. METHODS: 302 patients with AUB, underwent hysteroscopy and in 86 cases, also a transvaginal ultrasonography before hysteroscopy was performed. Results were compared with the histological diagnosis. RESULTS: The diagnostic accuracy of hysteroscopy was very high in the cases of endometrial carcinoma (sensibility 100%, specificity 99%), and lower in the cases of endometrial hyperplasia (sensibility 69%, specificity 72%) and endometrial atrophy (sensibility 29% and specificity 97%). Sonography proved to be less reliable in the diagnosis of endometrial pathology (carcinoma: sensibility 57%, specificity 100%, hyperplasia: sensibility 62.5% specificity 63%). The results of this study show that sonography may be used as a first choice diagnostic test in the investigation of women with AUB. CONCLUSIONS: Hysteroscopy represent a second diagnostic step for achieving a proper histologic diagnosis.     

Oxygenation-Ozonization of Blood During Extracorporeal Circulation (EBOO). Part III: A New Medical Approach

During the past decade, we have investigated a new method for oxygenation-ozonization (O₂-O₃) of human heparinized blood during extracorporeal circulation using standard hollow fiber oxygenators. While ordinary oxygenators are currently used in cardiopulmonary bypass, they become clogged within a few minutes owing to the activating effect of O₃ in platelets. The problem has been solved by using albumin-coated/oxygenators and suitable O₃ concentrations that have been selected on the basis of extensive biochemical tests. Preliminary clinical studies are promising, particularly in regard to vascular diseases, but the cost-benefit parameter of this method will become clear once a multicenter clinical trial will be completed.     

Bit Rate Reduction of Digitized Speech Using Entropy Techniques

We present the results of a study to reduce the bit rate of speech that has been digitized with a continuously variable slope delta modulator (CVSD) operating at 16, 24, and 32 kbits/s. The theoretical reduction is found from the bit stream entropy. The actual reduction, via Huffman coding, is within 1-2 Percent of the theoretical value. The conditional entropy indicates that additional bit rate reduction can be achieved if we use a set of Huffman codes, conditioned on the past CVSD bits. A third technique, tandem coding, using a maximum likelihood predictor in tandem with run length and Huffman coding, is also investigated. Using these entropy techniques, bit rate reductions of 11-25 percent are achieved for the CVSD rates considered. The paper concludes with a study of the buffer requirements needed to support these entropy coders.     

Identification and estimation of tocotrienols in the annatto lipid fraction by gas chromatography-mass spectrometry

The lipid fraction of annatto (Bixa orellana L.) seeds was extracted with a Soxhlet apparatus with n-hexane and isolated by thin-layer chromatography. The fatty-soluble antioxidant fraction contained only tocotrienols, mainly δ-tocotrienol, but no tocopherols. The presence of tocotrienols was confirmed by gas chromatography-mass spectrometry. The quantities of δ-tocotrienol were 140–147 mg/100 g dry seeds and 5.2–5.5% wt/wt of lipid extract, determined by gas chromatography and high-performance liquid chromatography, respectively. Currently no vegetable species seems to contain comparable concentrations of δ-tocotrienol.