No abstract

In a medium term scenario hybrid powertrain and Internal Combustion Engine (ICE) downsizing represent the actual trend in vehicle technology to reduce fuel consumption and CO2 emission. Concerning downsizing concept, to maintain a reasonable power level in small engines, the application of turbocharging is mandatory both for spark ignited (SI) and compression ignited (CI) engines. Following this aspect, the possibility to couple an electric drive to the turbocharger (electric turbo compound) to recover the residual energy of the exhaust gases is becoming more and more attractive, as demonstrated by several studies around the world and by the current application in the F1 Championship. The present paper shows the first numerical results of a research program in collaboration between the Universities of Pisa and Genoa. This first study is focused on the evaluation of the benefits resulting from the application of an ETC (Electric Turbo Compound) to a small twin-cylinder SI engine (900 cm3). Starting from the experimental maps of two turbines and one compressor, the complete model of a turbocharged engine was created using the AVL BOOST one-dimension code. The numerical activity then moves to the whole vehicle/powertrain modelling, considering three driving cycles and two different vehicle configurations, in order to verify the effectiveness of the proposed ETC solution. Results show that the adoption of ETC is not advantageous if used for a conventional turbocharger turbine, if the target is to optimize the overall efficiency in one specific operating point of the ICE, like in the case of range-extended electric vehicles. Besides, ETC can slightly improve the average overall efficiency when the ICE must provide variable power output, as in the case of conventional or hybrid vehicles. However, the major benefits coming from ETC are the boost range extension in the lowest engine rotational speed region and a possible reduction of turbo lag, which are key points in parallel-hybrid and especially in conventional vehicles. Concerning the whole vehicle/powertrain simulation, first results show that the ETC does not improve fuel economy of the smaller vehicle, especially when employed in urban cycles. The ETC is much more advantageous in the case of the larger vehicle, particularly when extra-urban roads or motorways are considered

Abstract. p53 wild-type is a tumor suppressor gene involved in DNA gene transcription or DNA repair mechanisms. When damage to DNA is unrepairable, p53 induces programmed cell death (apoptosis). The mutant p53 gene is the most frequent molecular alteration in human cancer, including breast cancer. Here, we analyzed the genetic alterations in p53 oncogene expression in 55 patients with breast cancer at different stages and in 8 normal women. We measured by ELISA assay the serum levels of p53 mutant protein and p53 antibodies. Immunohistochemistry and RT-PCR using specific p53 primers as well as mutation detection by DNA sequencing were also evaluated in breast tumor tissue. Serological p53 antibody analysis detected 0/8 (0%), 0/4 (0%) and 9/55 (16.36%) positive cases in normal women, in patients with benign breast disease and in breast carcinoma, respectively. We found positive p53 mutant in the sera of 0/8 (0.0%) normal women, 0/4 (0%) with benign breast disease and 29/55 (52.72%) with breast carcinoma. Immunohistochemistry evaluation was positive in 29/55 (52.73%) with mammary carcinoma and 0/4 (0%) with benign breast disease. A very good correlation between p53 mutant protein detected in serum and p53 accumulation by immunohistochemistry (83.3% positive in both assays) was found in this study. These data suggest that detection of mutated p53 could be a useful serological marker for diagnostic purposes.

Storing hydrogen is one of the major problems concerning its utilization on board vehicles. Today hydrogen can be compressed and stored at 200 or 350 bar (it is foreseen that in a near future storage pressure will reach 700 bar, according to new expected regulations and using tanks in composite materials) or cryogenically liquefied. An alternative solution is storing hydrogen in the form of ammonia that is liquid at roughly 9 bar at environmental temperature and therefore involves relatively small masses and volumes and requires light and low-cost tanks. Moreover, ammonia contains almost 18% hydrogen by mass and, by volume, liquid ammonia contains 1.7 times as much hydrogen as liquid hydrogen. It is well known that ammonia can be burned directly in I.C. engines, however a combustion promoter is necessary to support combustion especially in the case of high-speed S.I. engines. Among the potential promoters, hydrogen is worthy of note, since it is carbon free and counteracts ammonia combustion characteristics. As a matter of fact, hydrogen has high combustion velocity and wide flammability range, whereas ammonia combustion is characterized by low flame speed, low flame temperature, narrow flammability range, high ignition energy and high self-ignition temperature. The experimental activity shown in this paper is correlated with a project that is focused on a range-extended electric vehicle involving an ammonia-plus-hydrogen I.C. engine and where hydrogen is obtained from ammonia by means of on-board catalytic reforming. Accordingly, the test engine is a 505 cm₃ Lombardini twin-cylinder S.I. engine that is well suited to power the onboard electric generator and the activity is aimed at determining proper air-ammonia-hydrogen mixture compositions at actual operating speeds and loads of the engine connected to the electric generator. Hydrogen and ammonia are separately injected in the gaseous phase. The only mechanical modification of the engine involves the intake manifold, where electro-injectors for hydrogen and for ammonia (conventional ones for CNG application with appropriate modification to inner parts) are added to the original ones for gasoline. The experimental results confirm that it is necessary to add hydrogen to air-ammonia mixture to improve ignition and to increase combustion velocity, with ratios that depend mainly on load and less on engine speed. Brake power is less than with gasoline, due to mixture poor volumetric heating value and to ammonia low flame speed that penalizes engine brake thermal efficiency. The amount of hydrogen needed by the engine is compatible with the flow rate provided by the reformer, except at cold start. The maximum NOx emission is 11.5 g/kWh at half load and 4500 rpm, without catalytic reduction

Abstract. the aim of this study was to compare the sensitivity of the serological level of anti-p53 antibodies in breast cancer patients and to correlate its expression level with patient age, histological stage and grade of tumor differentiation. total p53 protein expression (mutant and wild-type) was also determined in the breast cancer tissues using immunohistochemistry (ihc). the serological levels of mutant p53 expression were found to be age-dependent, reaching the highest level at 50 years of age. Faint or low detection was observed in patients ≤30 years of age. Anti-p53-antibodies were detected in patients ≤40 and ≥61 years of age. The serological levels of mutant p53 protein were highly detected in all stages of breast cancer, including the early stages. however, anti-p53 antibodies reached a high level of detection only in stage iii breast carcinomas. no expression was found in patients with benign breast disease. the detection of p53 mutations was dependent on the grade of tumor differentiation, achieving the highest level in the poorly differentiated breast carcinomas. results from ihc were highly correlated with serological p53 mutational analysis. Our findings indicate that mutant p53 in serum is a promising novel parameter for the evaluation of cellular biology and the prognosis of breast cancer from its early stages using blood samples. anti-p53 antibodies were demonstrated to be less sensitive in this study. it is also possible to use the expression of mutant p53 protein as a molecular marker to differentiate benign breast disease from breast carcinoma prior to surgery.

Homogeneous-charge, compression-ignition (HCCI) combustion is triggered by spontaneous ignition in dilute homogeneous mixtures. The combustion rate must be reduced by suitable solutions such as high rates of Exhaust Gas Recirculation (EGR) and/or lean mixtures. HCCI is considered a very effective way to reduce engine pollutant emissions, however only a few HCCI engines have entered into production. HCCI combustion currently cannot be extended to the whole engine operating range, especially to high loads, since the use of EGR displaces air from the cylinder, limiting engine mean effective pressure, thus the engine must be able to operate also in conventional mode. This paper concerns a study of an innovative concept to control HCCI combustion in diesel-fuelled engines. The concept consists in forming a pre-compressed homogeneous charge outside the cylinder and gradually admitting it into the cylinder during the combustion process. In this way, combustion can be controlled by the transfer flow rate and high pressure rise rates, typical of standard HCCI combustion, can be avoided. This new combustion concept was called Homogenous Charge Progressive Combustion (HCPC). The paper illustrates a CFD analysis focused on improving efficiency and reducing pollutant emissions at medium and heavy load. Different geometries of the transfer duct were considered. Results show negligible soot emission up to equivalence ratios around 0.85, with indicated efficiency around 46 %. As well, a moderate level of external cooled EGR allows reducing NOx emissions up to levels that are typical of low-temperature combustion

Reactivity-controlled compression ignition combustion has proved to be effective in reducing the pollutant emissions and the fuel consumption in four-stroke internal-combustion engines. The application of this combustion mode to portcontrolled crankcase-scavenged two-stroke engines also seems promising to avoid short-circuiting of fresh charge and to take advantage of the intrinsic residual exhaust gas. Accordingly, a computational study of a small-bore two-stroke dualfuel direct-injection reactivity-controlled compression ignition engine was made including computational fluid dynamics simulations and zero-dimensional modeling. The zero-dimensional model is used to supply suitable initial conditions for the computational fluid dynamics simulations and to generate useful operating maps. These maps predict the engine behavior, highlighting the conditions where combustion would be controllable by means of in-cylinder reactivity stratification. The computational fluid dynamics simulations were validated against experimental data under motored and fired conditions, and the spray model was calibrated against dedicated bench tests. The in-cylinder behavior was explored to understand the effect and the importance on the engine operation of several types of stratification, including thermal stratification and reactivity stratification caused by the scavenging process and fuel injections. The models emphasize the importance of the exhaust gas thermal content which can promote combustion. Furthermore, its stratification in the combustion chamber due to the scavenging process, together with the reactivity stratification caused by the dual-fuel injection is able to change both the combustion phasing and the combution duration, thereby increasing the efficiency and reducing the combustion roughness.

The paper describes an experimental study concerning the feasibility of using bio-oil obtained from flash pyrolysis of wood for fuelling diesel power plants. The research is based on various tests aimed at verifying relevant operative characteristics of the fuel: spray analyses, engine tests, thermogravimetric analyses (TGA), single-drop reactor tests and corrosion tests. The spray analyses show that the achievement of a satisfactory atomisation with flash-pyrolysis oil is problematic. The engine experimentation shows that flash-pyrolysis oil needs to be modified or mixed (e.g. with alcohol) to make self ignition possible. Besides, unacceptable build-up of carbonaceous deposits, injection system clamping and engine seizure occur. Very large char generation is the main finding of the tests in the TGA apparatus and in the single-drop atmospheric reactor (“drop-tube”). The corrosion tests demonstrate that steel undergoes fast erosion by contact of flash-pyrolysis oil. All these findings show that characteristics of current-production flash-pyrolysis oil are not suited for its utilisation in diesel engines