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Studies are presented which demonstrate that: (1) irradiation of titanium and zinc oxide pigments produces singlet oxygen; (2) irradiation of titanium dioxide pigments in water yields, hydrogen peroxide; and (3) the formation of singlet oxygen and hydrogen peroxide correlates with chalking tendencies of the pigments. These findings, together with the results of quenching studies, are interpreted in terms of a working hypothesis, for the generation of reactive oxidants, which ties together previous work into a unified scheme. The relative chalking rates of anatase and rutile titanium dioxide as well as the improvement of chalk resistance by surface treatment, are discussed within the framework of this scheme. The role of singlet oxygen in the chalking process, the importance of its presence with regard to the control of chalking, and possible mechanisms for its formation are also discussed.

Presents results for April‐September 1996 from the Multi‐layer Atmospheric CHemistry model, Oslo (MACHO), a regional scale photo‐chemistry model, and compares to measurements. Initial and lateral boundary concentrations are provided by a global CTM (chemical tracer model). As a base run, monthly averaged concentrations for June 1996 are used as initial and lateral boundary concentrations. The sensitivity of the interior model domain to the lateral boundaries is analyzed by comparing the base run with a model run with lateral boundary concentrations updated at six‐hour intervals. In the boundary layer over Europe, differences between the two runs are small both for accumulated excesses and for concentrations on individual days, indicating that ozone levels here are determined predominantly by local European scale sources. in the free troposphere, however, the effects of the lateral boundary concentrations are shown to be significant.

The technical Press had an opportunity in July to view recent work of the Admiralty Materials Laboratory, near Poole, Dorset. This department was set up in 1947 and is responsible for materials research on a wide front, but angled, of course, to the Navy's particular requirements.

BASF is to erect plant in Ludwigshafen for the production of 90,000 tons of acrylic acid a year from propylene. The capital investment costs are estimated at about DM 100 million, including those for the necessary infrastructure measures.

A frequent contributor to public discussions on polymer technology and author of numerous papers and articles, Mr. Anthony Charles (Tony) Jolly, (45), has been appointed technical sales manager of the Kollercast Group of Synthetic Resins Ltd.

The introduction of inks that cured, rather than dried, brought a completely new solution to the problem of drying. Ink is physically a liquid and will only dry when excited by some form of radiation. This is available in two forms.

THE HARDCORE staff establishment at the Library Association has been in a positive tizzy of excitement since somebody ‘leaked’ to them a couple of months ago the news that NEW LIBRARY WORLD is to have a new Editor.

ABM Chemicals Ltd is exhibiting its range of photosensitisers for uv curing including the Glocure benzoin ethers. These highly cost effective materials ensure maximum utilisation of uv energy for the polymerisation process.

THE Deutsche Versuchsanstalt für Luft‐fahrt—known for short as the D.V.L.—at Berlin‐Adlershof, is the central establishment for aeronautical research in Germany. Hitherto the D.V.L. had as its special prerogative the testing of aircraft and aero‐engines for certificates of airworthiness. Since April 1, 1933, the Inspection Department has passed under the authority of the “Reichsamt für Flugsicherung” (Air Security Board), but it has not actually been separated from the D.V.L., continuing to have its premises at the D.V.L. establishment. (Further details of the Inspection Department are given later.)

To characterise the optical performance of organic multi‐mode optical waveguides integrated with printed circuit board (PCB) and to demonstrate the feasibility of 2.5 and 10 Gbps optical interconnection in board‐level, respectively.

This paper provides both qualitative and quantitative approaches for the characterization the wave guide performance, i.e. using loss measurement, optical beam profiling, ethernet verification, and eye‐diagram testing. In addition to wave guide loss measurement, the most significance part of the work reported in this paper is to evaluate optical wave guides with coupled VCSELs, by which a 3 dB coupling design budget can thus be identified. Furthermore, by artificially manipulating coupling conditions, practical concerns of EOPCB integration, including waveguide geometry, VCSEL driving power, alignment tolerance, coupling spacing, etc. are studied.

Thermal stability studies related to PCB lamination processes show the feasibility of organic waveguides integrated to traditional PCB manufacturing. For a direct VCSEL/PD coupling scheme, a 3 dB power budget is experimentally identified. For short reach optical interconnection, 10 Gbps up to 17 cm propagation on PCB can be achieved by using 50×50 μm multi‐mode organic waveguides, where a±25 μm tolerance of optical alignment is compatible to the design rules of PCB.

The value of the paper lies in its systematic approaches to identify the waveguide performance through both qualitative and quantitative indices. The correlation between geometry design, processes, coupling conditions, and optical performance of organic waveguides explored in detail. Not only is a standard eye‐diagram test used to verify the waveguide at 2.5 and 10 Gbps bandwidth, but also a prototype of optical data‐communication on giga‐ethernet is demonstrated for long term stability. Following these analytical methods, readers can understand more about the optical performance of waveguides when designing optical interconnection for high speed electro‐optical integrated PCBs.