Viscometric properties of viscosity index improvers in lubricant base oil over a wide temperature range. Part I: Group II base oil

Capillary viscometry has been employed to measure the viscosities of dilute polymer solutions over the temperature range ‐10 to 150 °C. A Group II base oil containing 95% saturates was used as solvent for an olefin copolymer (OCP), a hydrogenated diene copolymer (HDP), and a polymethacrylate (PMA). These three polymers represent the three major families of viscosity index (VI) improvers used nowadays in lubricant formulations. Intrinsic viscosities and Huggins' constants were also determined. The thickening effects of the olefin copolymer and the hydrogenated diene copolymer were found to be higher at low temperatures (e.g., 40 °C) than at higher ones (e.g., 100 °C), which phenomenon was attributed to stronger intermolecular hydrodynamic interactions at low temperatures, as indicated by the Huggins constants. For the hydrogenated diene copolymer and the polymethacrylate polymer, the viscosity increased abruptly when the temperature went below 10 °C. This unusual observation was attributed to the crystallisation of a small fraction of the base oil. Based on the intrinsic viscosity data, it was concluded that at temperatures between 10 and 150 °C, the polymer coil dimension remains a constant for the olefin copolymer and the hydrogenated diene copolymer VI improvers, but increases with increasing temperature for the polymethacrylate VI improver.     

Estimating the geotechnical properties of heterogeneous rock masses such as flysch

The design of tunnels and slopes in heterogeneous rock masses such as flysch presents a major challenge to geologists and engineers. The complex structure of these materials, resulting from their depositional and tectonic history, means that they cannot easily be classified in terms of widely used rock mass classification systems. A methodology for estimating the Geological Strength Index and the rock mass properties for these geological formations is presented in this paper. Electronic Publication     

Géologie de l'ingénieur appliquée aux études de,mise en valeur d'un site historique et de son environnement,Crète,Grèce

The paper deals with the engineering Geological studies applied to the protection and development of a historical site, the Arkadi Monastery, in Crete, (XIIth, century). The geomorphological mapping allows to point out the areas which are concerned by the problems of environmental protection—natural sites, plateaus, karstic phenomenons, gorges. Such a mapping may also be used for the protection against floods and for the design of the plateaus drainage. The geological mapping deals with, the whole area, and takes into account the lithology, the weathering, the problems concerning the earthworks and the foundations. Slope stability is presented on a separate map. The hydrological study deals with the different conditions of the area—alluvial aquifers, scattered aquifers, karstic aquifers—and proposes solutions for the water supply and for the drainage in the area—alluvial aquifers, scattered aquifers, karstic aquifers—and proposes solutions for the water supply and for the drainage in the area. A special attention is paid to the weathering of the building stones which were used for the construction of the monastery —limestones—and to the survey of similar deposits with a view to its restoration. Finally, the study deals with the seismic risks—neotectonic phenomenons, and statistical interpretation of seismic data.     

A sensor monitoring system for telemedicine,safety and security applications

A sensor system capable of medical, safety and security monitoring in avionic and other environments (e.g. homes) is examined. For application inside an aircraft cabin, the system relies on an optical cellular network that connects each seat to a server and uses a set of database applications to process data related to passengers’ health, safety and security status. Health monitoring typically encompasses electrocardiogram, pulse oximetry and blood pressure, body temperature and respiration rate while safety and security monitoring is related to the standard flight attendance duties, such as cabin preparation for take-off, landing, flight in regions of turbulence, etc. In contrast to previous related works, this article focuses on the system’s modules (medical and safety sensors and associated hardware), the database applications used for the overall control of the monitoring function and the potential use of the system for security applications. Further tests involving medical, safety and security sensing performed in an real A340 mock-up set-up are also described and reference is made to the possible use of the sensing system in alternative environments and applications, such as health monitoring within other means of transport (e.g. trains or small passenger sea vessels) as well as for remotely located home users, over a wired Ethernet network or the Internet.     

Selection of TBM and geotechnical assessment of a microtunnel in a difficult geological environment: a case of a natural gas pipeline beneath an active landslide (Albania)

Bulletin of Engineering Geology and the Environment - This present paper presents an adopted methodology for Micro Tunnel Boring Machine (TBM) selection, based on the results of a...     

Reviews

DROUGHT AND FAMINE IN ETHIOPIA Editor: Abdul Mejid Hussein. African Environment Special Report No. 2, The International African Institute, London, 1976,121 pp. £1.50.

HEDGING (A Practical conservation handbook) Alan Brooks, The British Trust for Conservation Volunteers, The Zoological Gardens, Regents Park, London, 1975. 117 pp. £2.10 inc. postage.

THREE JOURNALS Habitat: Published by : The Council for Nature, The Zoological Gardens, Regents Park, NW1 4RY. At £2.50, or £5.00 per annum.

Recreation News: Published by: The Countryside Commission , John Dower House, Crescent Place, Cheltenham, Glos., GL50 3RA.

The International Journal of Environmental Studies: Published by : Gordon Breach Science Publishers Ltd., 42 William IV Street. London, W.C.2. £17.50 for individuals, £35.00 for Libraries. Habitat

A HISTORY OF LANCASHIRE J.J. Bagley, Phillimore & Co. Ltd., London & Chichester 1976. 128 pp. £4.95.     

Applicability of the geological strength index (GSI) classification for very weak and sheared rock masses. The case of the Athens Schist Formation

 The Athens Schist Formation includes a wide variety of metasedimentary rocks, varying from strong or medium strong rocks such as sericite metasandstone, limestone, greywacke, sericite schist through to weak rocks such as metasiltstone, clayey and silty shale and phyllite. The overall rock mass is highly heterogeneous and anisotropic owing to the combined effect of advanced weathering and severe tectonic stressing that gave rise to intense folding and shearing followed by extensional faulting, which resulted in highly weathered rock masses and numerous shear and/or mylonite zones with distinct downgraded engineering properties. This paper is focused on the applicability of the GSI classification system to these highly heterogeneous rock masses and proposes an extension of the GSI system to account for the foliated or laminated weak rocks in the lower range of its applicability. Received: 5 March 1998 · Accepted: 13 July 1998     

Design Optimization of a Portable Thermophoretic Precipitator Nanoparticle Sampler

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are developing methods for characterizing diesel particulate matter in mines. Introduction of novel engine and exhaust aftertreatment technologies in underground mines is changing the nature of diesel emissions, and metrics alternative to the traditional mass-based measurements are being investigated with respect to their ability to capture changes in the properties of diesel aerosols. The emphasis is given to metrics based on measurement of number and surface area concentrations, but analysis of collected particles using electron microscopy (EM) is also employed for detailed particle characterization. To collect samples for EM analysis at remote workplaces, including mining and manufacturing facilities, NIOSH is developing portable particle samplers capable of collecting airborne nano-scale particles. This paper describes the design, construction, and testing of a prototype thermophoretic precipitator (TP) particle sampler optimized for collection of particles in the size range of 1–300 nm. The device comprises heated and cooled metal plates separated by a 0.8 mm channel through which aerosol is drawn by a pump. It weighs about 2 kg, has a total footprint of 27 × 22 cm, and the collection plate size is approximately 4 × 8 cm. Low power consumption and enhanced portability were achieved by using moderate flow rates (50–150 cm³/min) and temperature gradients (10–50 K/mm with ΔT between 8 K and 40 K). The collection efficiency of the prototype, measured with a condensation particle counter using laboratory-generated polydisperse submicrometer NaCl aerosols, ranged from 14–99%, depending on temperature gradient and flow rate. Analysis of transmission electron microscopy images of samples collected with the TP confirmed that the size distributions of collected particles determined using EM are in good agreement with those determined using a Fast Mobility Particle Sizer.

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