The Italian national survey of indoor radon exposure

An investigation is being developed by the Camitato Nazionale per la Ricerca e per lo Sviluppo dell'Energia Nucleare e delle Energie Alternative, ENEA, to assess the indoor exposure of the Italian population. The programme, which started in 1982, includes regional and local surveys in all the administrative districts and intensive investigations of factors which influence indoor radon levels. The survey is organized by statistical areas of sampling to obtain representative samples of houses. The definition of the areas takes into account basic parameters e.g. geolithological environments, radon soil gas from underlying soils and rocks, specific activities of local building materials, climatic and seasonal variations, building technology, types of houses and town planning. The collected data may also be used for the compilation of radon risk maps to plan special monitoring and remedial actions if needed. Preliminary results concerning the above items are discussed.     

Smoke development at different energy flux levels in an NBS smoke density chamber

An automatically controlled high-energy flux heater has been developed and utilized in an NBS Smoke Density Chamber.     

On the potential of combining neutron activation analysis and particle induced X-ray emission (PIXE) for micro- and microdistribution analysis of hard metals in human tissues

Tungsten carbide and cobalt are the main components of hard metal alloy while other metals such as chromium, niobium, tantalum, titanium and vanadium are sometimes added in smaller amounts. Exposure to hard metal dusts can induce a lung fibrosis with cobalt playing a major role. In order to provide information on the role that each metal may have in causing this disease, determination of the total content and the distribution of inhaled metals in lung tissue of hard metal workers is of paramount importance. However, samples such as transbronchial biopsy and bronchoalveolar lavage (BAL), often used in the medical diagnosis of pneumoconiosis, only allow for a small amount of material. This calls for sensitive and accurate analytical procedures for microdetermination and distribution of metals in pulmonary tissue and cellular material, such as macrophages. This work proposes a combination of sophisticated analytical techniques such as neutron activation analysis (NAA), currently applied to the determination of the total concentration of more than 30 elements in biological specimens, and PIXE analysis, particularly microPIXE, which has a great potential for microdistribution analysis in small biological samples. Principles and perspectives for the combined use of these techniques for the analysis of human tissue are outlined and discussed. NAA: determination of hard metals in lung tissue are carried out by neutron irradiation (2 × 10¹⁴ neutrons cm⁻² s⁻¹) in the HFR reactor of Petten. After neutron activation, radiochemical separations of ⁶⁰Co, ¹⁸⁷W, ¹⁸²Ta, ⁵¹Cr followed by computer-based high resolution gamma ray spectrometry allow the measurement of these elements in pulmonary tissues with sensitivities ranging from 10⁻⁴ μg (Cr) to 10⁻⁶ μg (W). PIXE: this technique is multielemental and of relatively high sensitivity (μg/g) even in small total sample masses of from 10 to 100 μg, thus allowing the analysis of parts of needle biopsies. Whereas PIXE has been successfully applied to many medical problems, its usefulness is limited in the total samples analysis for cobalt-related hard metal disease, due to the low levels of cobalt in tissue combined with severe element interferences from the generally more abundant metal, iron. Nevertheless, microPIXE, a special variety of the method scanning over the sample with a focussed ion beam of about 2 × 2 μm², could complement the NAA findings in total samples in the sense of achieving a microdistribution analysis of hard metals (including cobalt) in suitable thin tissue sections.The availability of specialized facilities at the JRC such as the powerful HFR reactor (Petten), the NAA laboratories (Ispra) and the microPIXE facility (Geel) could represent a European ‘reference pole’ for the study of metals in tissues of hard metal diseased subjects.     

Gravity driven counterflow through an open door in a sealed room

Flow measurements using tracer gas techniques were made on the exterior doorway of a test house for indoor-outdoor temperature differences of 0.5–45 K. The time for door opening and closing was constant at 3.75 s, and fully open hold time varied from 0.5 s to 120 s. Predictions of a variable density steady flow model were in good agreement with the measurements when adjustments were made for the time-varying size of the opening and for the effect of cross-stream mixing between the incoming and outgoing air streams. The flow rate is shown to be governed by an effective density very close to the average of inflow and outflow densities, and the control condition at the doorway is fixed by the jet-like behavior of the inflow stream. Dependence of cross-stream mixing on interfacial stability caused the orifice and coefficient to increase from 0.4 to 0.6 as temperature difference increased. This varying orifice coefficient is well represented by the combination of a discharge coefficient for streamline contraction combined with a mixing coefficient which accounts for mixing between the inflow and outflow.     

Post-crash fire testing of titanium fuselages

The problem … maintain fuselage integrity and a survivable cabin environment during a post-crash fire. Its high melting point made titanium an attractive candidate for the large-scale test discussed here. Note: This paper is an adaptation of Report No. FAA-RD-71-3, “Titanium Fuselage Environmental Conditions in Post-Crash Fires,” prepared by the author for the Federal Aviation Administration. The report was also the basis for Mr. Sarkos’ presentation at the 75th Annual Meeting of the National Fire Protection Association in San Francisco on May 18, 1971.     

Object–Oriented Enterprise Modeling and Simulation of AEC Projects

In this paper we describe an object–oriented framework for developing enterprise models of Architecture, Engineering, Construction projects, and a methodology for formalizing these models such that they can be used for discrete event simulation of information processing and coordination in project execution. The simulation results can be used to predict the probable effects of carrying out proposed changes in planning and managing projects.
In our enterprise modeling framework we represent engineering design projects in terms of deliverables (requirements and solutions), plans (activities and process relations), and organization (participants and organizational relations). The resulting project model is the starting point for identifying coordination requirements between project team participants. Our methodology uses matrix techniques derived from qualtiy function deployment (QFD) to identify interactions between project requirements and solutions and calculate measures of product complexity . We then describe information flow between project activities in a similar matrix and calculate measures of process uncertainty . Finally, we identify the responsibilities of project team members and use a matrix to point out organizational interdependencies .
We apply our framework and methodology to model and simulate engineering design for a major extension of an electrical power substation. Our simulation results demonstrate how project performance is contingent on the fit between the project policies and the objectives and preferences of the project team.