Streamlined life cycle assessment of transparent silica aerogel made by supercritical drying

This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2011 ElsevierWhen developing sustainable building fabric technologies, it is essential that the energy use and CO2 burden arising from manufacture does not outweigh the respective in-use savings. This study investigates this paradigm by carrying out a streamlined life cycle assessment (LCA) of silica aerogel. This unique, nanoporous translucent insulation material has the lowest thermal conductivity of any solid, retaining up to four times as much heat as conventional insulation, whilst being highly transparent to light and solar radiation. Monolithic silica aerogel has been cited as the ‘holy grail’ of future glazing technology. Alternatively, translucent granular aerogel is now being produced on a commercial scale. In each case, many solvents are used in production, often accompanied by intensive drying processes, which may consume large amounts of energy and CO2. To date, there has been no peer-reviewed LCA of this material conducted to the ISO 14000 standard. Primary data for this ‘cradle-to-factory gate’ LCA is collected for silica aerogel made by low and high temperature supercritical drying. In both cases, the mass of raw materials and electricity usage for each process is monitored to determine the total energy use and CO2 burden. Findings are compared against the predicted operational savings arising from retrofitting translucent silica aerogel to a single glazed window to upgrade its thermal performance. Results should be treated as a conservative estimate as the aerogel is produced in a laboratory, which has not been developed for mass manufacture or refined to reduce its environmental impact. Furthermore, the samples are small and assumptions to upscale the manufacturing volume occur without major changes to production steps or equipment used. Despite this, parity between the CO2 burden and CO2 savings is achieved in less than 2 years, indicating that silica aerogel can provide a measurable environmental benefit.This work is funded by the EPSRC, Brunel University and Buro Happold Ltd, the University of Bath is funded by the EPSRC grant EP/F018622/1

The Photonic Lantern

Photonic lanterns are made by adiabatically merging several single-mode cores into one multimode core. They provide low-loss interfaces between single-mode and multimode systems where the precise optical mapping between cores and individual modes is unimportant.Comment: 45 pages; article unchanged, accepted for publication in Advances in Optics and Photonic

Groundwater reinjection and heat dissipation: lessons from the operation of a large groundwater cooling system in Central London

The performance of a large open-loop groundwater cooling scheme in a shallow alluvial aquifer at a prominent public building in Central London has been monitored closely over its first 2 years of operation. The installed system provided cooling to the site continuously for a period of 9 months between June 2012 and April 2013. During this period, c. 131300 m3 of groundwater was abstracted from a single pumping well and recharged into a single injection borehole. The amount of heat rejected in this period amounts to c. 1.37 GWh. A programme of hydraulic testing was subsequently undertaken over a 3 month period between July and October 2013 to evaluate the performance of the injection borehole. The data indicate no significant change in injection performance between commissioning trials undertaken in 2010 and the most recent period of testing, as evidenced by comparison of injection pressures for given flow rates in 2010 and 2013. Continuous temperature monitoring of the abstracted water, the discharge and a number of observation wells demonstrates the evolution of a heat plume in the aquifer in response to heat rejection and subsequent dissipation of this heat during the 18 month planned cessation

The high-lying 6^6Li levels at excitation energy around 21 MeV

The $^3$H+$^3$He cluster structure in $^6$Li was investigated by the $^3$H($\alpha$,$^3$H $^3$He)n kinematically complete experiment at the incident energy $E_\alpha$ = 67.2 MeV. We have observed two resonances at $E_x^*$ = 21.30 and 21.90 MeV which are consistent with the $^3$He($^3$H, $\gamma$)$^6$Li analysis in the Ajzenberg-Selove compilation. Our data are compared with the previous experimental data and the RGM and CSRGM calculations.Comment: 12 pages, 6 figures. Accepted for publication in J. Phys. Soc. Jp

Development of Advanced NDE Ultrasonic Equipment

Recent studies to determine the probability of detection of nondestructive examination methods by the Air Force indicate that these capabilities are severely limited. One of the factors contributing to the insufficiency of ultrasonic testing is related to a general lack of versatility and capability of commercial ultrasonic equipment. Inadequate instrument reliability, inconsistent components including transducers, and uncertain calibration standards further compromise the potential utility of this method. Battelle Pacific Northwest Laboratories, under the sponsorship of the manufacturing Technology Division of the Air Force Materials Laboratory, is developing an advanced ultrasonic nondestructive testing system directed at resolving these defficiencies. As a result, this program will establish a modular ultrasonic system specification that will prevent near term obsolescence by permitting the addition of new technology such as ARPA developments in the form of additional or replacement modules. This paper will describe the Phase I and II tasks and objectives which are planned to establish an equipment specification, demonstrate initial prototype systems, and provide a procurement specification and technical manuals. Progress to date will be summarized

Managing the mutations: Academic misconduct Australia, New Zealand and the UK

Academic misconduct is a problem of growing concern across the tertiary education sector. While plagiarism has been the most common form of academic misconduct, the advent of software programs to detect plagiarism has seen the problem of misconduct simply mutate. As universities attempt to function in an increasingly complex environment, the factors that contribute to academic misconduct are unlikely to be easily mitigated. A multiple case study approach examined how academic misconduct is perceived in universities in in Australia, New Zealand and the United Kingdom via interviews with academics and administrators. The findings show that academic misconduct is a systemic problem that manifests in various ways and requires similarly diverse approaches to management. Greater consistency in policies and procedures, including a focus on preventative education for both staff and students, is key, to managing the mutations of academic misconduct that continue to plague the higher education sector globally

The development of a new measure of quality of life for children with congenital cardiac disease

The purpose of the study was to develop a questionnaire measuring health-related R1 quality of life for children and adolescents with congenital heart disease, the ConQol, that would have both clinical and research applications. We describe here the process of construction of a questionnaire, the piloting and the development of a weighted scoring system, and data on the psychometric performance of the measure in a sample of 640 children and young people recruited via 6 regional centres for paediatric cardiology from across the United Kingdom. The ConQol has two versions, one designed for children aged from 8 to 11 years, and the other for young people aged from 12 to 16 years. Initial findings suggest that it is a valid and reliable instrument, is acceptable to respondents, and is simple to administer in both a research and clinical context

Resonant Bend Loss in Leakage Channel Fibers

Leakage channel fibers, designed to suppress higher-order modes, demonstrate resonant power loss at certain critical radii of curvature. Outside the resonance, the power recovers to the levels offset by the usual mechanism of bend-induced loss. Using C$^2$-imaging, we experimentally characterize this anomaly and identify the corresponding physical mechanism as the radiative decay of the fundamental mode mediated by the resonant coupling to a cladding mode.Comment: 3 pages, 4 figures, submitted to Optics Letter