Design and analysis of a robust real-time engine control network

Increasing numbers of automotive control systems are being designed as distributed systems, with critical functions linked by electronic communications. This includes X-by-wire systems, which seek to replace mechanical or hydraulic linkages with electrical or communications links. These systems raise a number of new challenges: Safety is a function of the whole system rather than any one system feature. Thus, safety analysis and understanding must occur at the (complex) system level. A robust design process is essential to ensure that complex system issues and critical analysis occur at the right development stage and cover all appropriate parts of the system. This article provides a case study of a development project to show how these and other issues can be addressed. We describe the development of a communications network for a safety-related engine application that consists of a central electronic control unit (ECU) and a number of distributed actuators that are controlled via the network. We apply several techniques, such as hazard and scheduling analysis, to resolve safety and reliability issues     

Quasi-Interpolants with Tension Properties from and in CAGD

We present C² quasi-interpolating schemes with tension properties. The B-splines like functions used in the quasi-interpolanting schemes are parametric cubic curves and their shape can be easily controlled via tension parameters which have an immediate geometric interpretation. Applications to the problem of approximation of curves with shape-constraints are discussed.     

Proton binding onto soil by nonelectrostatic models: isolation and identification of mineral contributions

In this paper a methodological approach is proposed to validate mechanistic modeling for proton binding onto active sites of mineral and soil samples by reducing the uncertainty and arbitrariness of model schematization. This approach is based on the quantitative formulation (X-ray calibration method) of a simulating mineral mixture (SMM) accounting for the main mineral phases in the soil (quartz, goethite, hematite, muscovite, clinochlore). Mineral and organic contributions were separated by comparing titration curves of river sediment and SMM. Specific mineral contributions to the acid properties of SMM were separated by comparing titration models of SMM and single minerals. Different nonelectrostatic models were used for titrations of SMM and single minerals: two-site/three-KH models (one amphoteric plus one monoprotic site) for clay minerals and SMM; one-site/two-KH models (one amphoteric site) for goethite and hematite; and a one-site/one-KH model (one monoprotic site) for quartz. Crossed-comparisons of titration models allow for identifying and quantifying the specific contributions of the distinct edge hydroxyl groups of iron oxides, clay minerals, and quartz in the different pH ranges. In particularthe amphoteric sites of aluminosilicates mainly contribute in the acid-neutral pH range, the amphoteric sites of iron oxides take part in the neutral-basic range, and finally the monoprotic edge hydroxyl groups of quartz react in the upper basic region of pH. The good simulation of the acid-base properties of SMM (according to single mineral titration models and quantitative composition by X-ray) confirms both model schematization and SMM formulation. Speciation diagrams of the active sites of the different mineral components (aluminosilicates, iron oxides, and quartz) were obtained by implementing the database of a dedicated software with the apparent equilibrium constants regressed by titration modeling of single minerals.     

Imaginary refractive-index effects on desert-aerosol extinction versus backscatter relationships at 351 nm: numerical computations and comparison with Raman lidar measurements

A numerical model is used to investigate the dependence at 351 nm of desert-aerosol extinction and backscatter coefficients on particle imaginary refractive index (mi). Three ranges (-0.005 < or = mi < or = -0.001, -0.01 < or = mi < or = -0.001, and -0.02 < or = mi < or = -0.001) are considered, showing that backscatter coefficients are reduced as /mi/ increases, whereas extinction coefficients are weakly dependent on mi. Numerical results are compared with extinction and backscatter coefficients retrieved by elastic Raman lidar measurements performed during Saharan dust storms over the Mediterranean Sea. The comparison indicates that a range of -0.01 to -0.001 can be representative of Saharan dust aerosols and that the nonsphericity of mineral particles must be considered.     

Integrated ambient ozone evaluation by passive samplers and clover biomonitoring mini-stations

An ozone monitoring network was set up using passive samplers and biological mini-stations of two clones of white clover (Trifolium repens L. cv. Regal), NC-R (O(3)-resistant) and NC-S (O(3)-sensitive). This paper reports on a pilot study performed in the period June-October 1999 in the Rome municipal area by using five biomonitoring mini-stations and ozone passive samplers with a new nitrite based design. This combined methodology can be used to obtain information on the biological implications of the injury due to tropospheric ozone. The two techniques can integrate data for the short-medium period and can be placed in different urban and rural sites, proving to be a very useful tool for ozone concentration mapping.     

Intranucleolar localization of DNA topoisomerase IIalpha is a distinctive feature of necrotic, but not of apoptotic, Jurkat T-cells

Two distinct types of cell death have been described: apoptosis and necrosis. However, it is becoming increasingly clear that the differences between these two types are far less numerous than initially thought. Morphological analyses might provide important information to distinguish apoptotic from necrotic samples. We recently reported that in necrotic, but not apoptotic, HL-60 human myeloid leukaemia cells, the nuclear protein topoisomerase IIalpha concentrated in nucleoli. In order to ascertain whether or not this phenomenon was restricted to a peculiar cell type or could be detected also in cells of lymphoid lineage, we performed an investigation aimed at defining the localization of topoisomerase IIalpha in apoptotic and necrotic Jurkat human T lymphoblastoid cells. Immunofluorescence staining demonstrated that topoisomerase IIalpha was excluded from the condensed chromatin of apoptotic cells, whereas in necrotic cells it was localized in discrete nuclear dots. Immuno-electron microscopy analysis showed that topoisomerase IIalpha was undetectable in nucleoli of normal and apoptotic cells, whereas it was present in the nucleolus of necrotic cells irrespectively of the type of inducer used (ethanol, H(2)O(2), HgCl(2)). Taken together, our findings identify topoisomerase IIalpha as a potential morphological marker useful to discriminate between apoptotic and necrotic cells.     

Poly(vinyl alcohol) as versatile biomaterial for potential biomedical applications

In this paper, we present some new case examples where the chemical versatility of poly (vinyl alcohol) (PVA) can be used for potential biomedical applications. PVA, the polymeric material used for designing new nanostructured devices, is water soluble, biocompatible and has excellent physical properties. We point out the possibility of obtaining wall-to-wall chemical hydrogels as well as microgels without diminishing the biocompatibility available in the starting PVA material. Injectability is another important factor to take into account in controlled drug delivery for gene therapy. In this respect, in this paper, established and more innovative methods are prospected in order to obtain particles with dimensions suitable for these applications.