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The inability of membranes to handle a wide spectrum of pollutants is an important unsolved problem for water treatment. Here we demonstrate water desalination via a membrane distillation process using a graphene membrane where water permeation is enabled by nanochannels of multilayer, mismatched, partially overlapping graphene grains. Graphene films derived from renewable oil exhibit significantly superior retention of water vapour flux and salt rejection rates, and a superior antifouling capability under a mixture of saline water containing contaminants such as oils and surfactants, compared to commercial distillation membranes. Moreover, real-world applicability of our membrane is demonstrated by processing sea water from Sydney Harbour over 72 h with macroscale membrane size of 4 cm2, processing ~0.5 L per day. Numerical simulations show that the channels between the mismatched grains serve as an effective water permeation route. Our research will pave the way for large-scale graphene-based antifouling membranes for diverse water treatment applications.

Results of an interlaboratory comparison on size characterization of SiO2 airborne nanoparticles using on-line and off-line measurement techniques are discussed. This study was performed in the framework of Technical Working Area (TWA) 34—“Properties of Nanoparticle Populations” of the Versailles Project on Advanced Materials and Standards (VAMAS) in the project no. 3 “Techniques for characterizing size distribution of airborne nanoparticles”. Two types of nano-aerosols, consisting of (1) one population of nanoparticles with a mean diameter between 30.3 and 39.0 nm and (2) two populations of non-agglomerated nanoparticles with mean diameters between, respectively, 36.2–46.6 nm and 80.2–89.8 nm, were generated for characterization measurements. Scanning mobility particle size spectrometers (SMPS) were used for on-line measurements of size distributions of the produced nano-aerosols. Transmission electron microscopy, scanning electron microscopy, and atomic force microscopy were used as off-line measurement techniques for nanoparticles characterization. Samples were deposited on appropriate supports such as grids, filters, and mica plates by electrostatic precipitation and a filtration technique using SMPS controlled generation upstream. The results of the main size distribution parameters (mean and mode diameters), obtained from several laboratories, were compared based on metrological approaches including metrological traceability, calibration, and evaluation of the measurement uncertainty. Internationally harmonized measurement procedures for airborne SiO2 nanoparticles characterization are proposed.

The current activities of the Time and Frequency Section of the CSIRO National Measurement Laboratory are outlined. In addition to the usual responsibilities of a national timing laboratory, these activities include: * Development of a trapped ion microwave frequency standard, * Development of reliable, low cost GPS common-view time transfer systems, * Two-way satellite time transfer, See also ADM001481. Presented at the Precise Time and Time Interval (PTTI) Planning Meeting (31st Annual) held in Dana Point, CA on 7-9 December 1999. Published in the Proceedings of the Precise Time and Time Interval (PTTI) Planning Meeting (31st Annual), p211-218, 1999.

Two-Way Satellite Time Transfer (TWSTT) is one of the most precise time transfer techniques, and time transfer using this method has been used between European and North American Time and Frequency laboratories on a regular basis. In the Asia-Pacific region four Time and Frequency laboratories have been involved in establishing a precise time transfer network using the TWSTT technique. After several continuous 24-hour TWSTT experiments between Communications Research Laboratory (CRL) in Japan and National Measurement Laboratory (NML) in Australia, a regular, twice weekly TWSTT link has been established since April 1998 using a Ku-band transponder on INTELSAT satellite 702 located at 177 deg. E. CRL and Shaanxi Astronomical Observatory of Chinese Academy of Science (CSAO) have just established a precise time transfer link using the TWSTT technique from October 1998. For this time transfer link we are using a Ku-band transponder on the JCSAT-3 satellite, which is owned by Japanese satellite communication company and is located at 128 deg. E. National Research Laboratory of Metrology (NRLM) in Japan is also planning to join the TWSTT link network with a link to CRL also using JCSAT-3 from March 1999. For the next step toward a global TWSTT network we are planning to connect the Asia-Pacific TWSTT link to European and North American time and frequency laboratories. Such a network of precise time transfer links will not only by itself be useful in contributing to TAI and UTC but also provide an accurate time transfer reference for other precise time transfer techniques such as the GPS carrier phase method., See also ADA415578. Published in Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (30th). Proceedings of a Meeting held at the Hyatt Regency Hotel, Reston Town Center, Reston, VA, 1-3 December 1998, p355-363.