Recycled aggregates and recycled aggregate concrete second state-of-the-art report developments 1945–1985

The extensive, but fragmented research on recycled concrete aggregates and recycled aggregate concrete, which has been carried out in various parts of the world from 1945 to 1985, has been collated to form a comprehensive state-of-the-art document. A thorough analysis of the data has been made, leading to a guide to the production and evaluation of recycled concrete aggregates as well as the design, production, and use of recycled aggregate concrete. The present document will be followed up by another state-of-the-art report on recycled aggregate concrete produced with mixed demolition rubble as recycled aggregate. The second document is also being prepared RILEM TC-37-DRC and will be published in this journal at a later date (53).     

Refurbishing Faestningens Materialgard： A Heritage Complex

F estningens Materialgard is a listed complex located in downtown Copenhagen. The refurbishment of the listed complex was studied to provide knowledge on how a process for refurbishing heritage buildings can be carried out successfully, as refurbishment of heritage buildings is often a complicated process. The process shows how to choose, evaluate and implement measures creating synergy between the interests of preserving heritage values and to develop affordable refurbishment that meets the requirements for the future use of the building. The refurbishment followed included restoration, energy upgrading and refurbishment of the individual buildings that make up the listed complex. The process focuses on the cooperation and dialogue between the parties involved. F estningens Materialgard is a case study where the Heritage Agency, the Danish Working Environment Authority and the owner as a team cooperated in identifying feasible refurbishment measures. Through the process the owner was supported by architects and engineers. Focus is put on how, to identify potential energy savings and, to decide on energy upgrading measures when refurbishing and restoring listed buildings. The refurbished Faestningens Materialgard is visualized in photos.     

Comparison of three methods for detection of herbal food supplement irradiation

A survey for irradiation of 106 herbal food supplements was carried out in Denmark in 2003. The results from three methods, two screening methods and a specific method, were compared: Direct epifluorescent filter technique/aerobic plate count (DEFT/APC), photostimulated luminescence (PSL) and thermoluminescence (TL) standardised by Comité Européen de Normalisation (CEN). Forty samples screened positive with the DEFT/APC method. However, the TL method could only confirm irradiation of 15 samples, 11 samples wholly irradiated and 4 samples with a minor irradiated ingredient. Thus, the DEFT/APC method gave a large number of false positive results, although the number of false negative results probably was very low. Only 7 of the 15 confirmed irradiated samples screened positive with the PSL screening method, the samples with low photon counts escaping detection. For 10% of the samples also the TL method was lacking in sensitivity, as not enough minerals could be isolated to get a signal over the minimum detection level. For such clean herbal food supplements no suitable method exists at all among the CEN standardised methods for irradiation detection.     

Assessment of the performance of organic and mineral-based insulation products used in exterior walls and attics in dwellings

The assessment of the performance of organic and mineral-based insulation products used in exterior walls and attics in traditional Danish housing estate was evaluated. The assessment covered the ability of the materials to be handled on site as well as measurements of the performance of the materials once installed and exposed to normal use of the dwellings and Danish weather conditions over a 2-year period. Evaluations were based on, on-site observations, thermographic observations and measurements of temperature and moisture conditions within the different materials used. Eight different products were used for thermal insulation including six organic and two mineral fibre materials. Loose-fill material and predefined fixed-shape products were used. The eight different products were installed in 16 dwellings, two neighbouring dwellings were insulated with each product. Exterior walls were constructed without PE vapour barriers while ceilings were constructed with PE vapour barriers.     

DCB-specimen loaded with uneven bending moments

A double cantilever beam specimen loaded with uneven bending moments (DCB-UBM) is proposed for mixed mode fracture mechanics characterisation of adhesive joints, laminates and multilayers. A linear elastic fracture mechanics analysis gives the energy release rate and mode mixity analytically for both isotropic and orthotropic materials. By varying the ratio between the two applied moments, the crack tip stress state can be varied from pure mode I to pure mode II for the same specimen geometry. The specimen allows stable crack growth. A special test fixture is developed to create uneven bending moments. As a preliminary example, the DCB-UBM specimen was used for characterising fracture of adhesive joints between two laminates of thermoset glass fibre reinforced plastic.     

UTRA/FDD RF Transceiver Requirements

Unified RF requirements are derived for an UMTS Terrestrial RadioAccess/Frequency Division Duplex (UTRA/FDD) compliant mobile transceiver. Aset of transceiver requirements are proposed with consideration to systemissues including duplex aspects. From these design-compatible requirements areproposed for each functional block in the transceiver.     

A measurement fixture suitable for measuring substrate noise in the UWB frequency band

This paper presents a measurement fixture suitable for measuring substrate carried noise for lightly doped substrates within the UWB frequency band. Signals coupling through the substrate are usually fairly weak and special precautions are taken to avoid any distortions that may be caused by the test fixture. The proposed measurement fixture is based on a modified ground-signal-ground (GSG) pad fixture. Parasitic effects in the measurement fixture are evaluated with help of an equivalent circuit model. From measured results, the presented fixture is shown to provide a measurement band from 3 to 10 GHz. As an example of the usability of the presented fixture a test-case using a class-E PA is presented. The noise injected by the class-E PA is measured using the proposed fixture as noise detector and the results are show to be accurate to within ±1.5 dB.     

Dietary differences among commercially important fishes in Lake Tanganyika assessed using stable isotope analysis

The pelagic fishery of Lake Tanganyika, which is largely made up of the three species Lates stappersii, Limnothrissa miodon, and Stolothrissa tanganicae, has been in decline, and there is no clear understanding of the primary underlying causes. It has been suggested that climate change has altered the primary productivity of the system, but detailed knowledge of the system's food web is required to elucidate the effect on higher trophic levels. The aim of this study is to determine the diet of the three commercially important fish species. Muscle tissue samples for stable isotope analysis were taken from February through April 2017, supplemented with stomach samples from L. stappersii for use in stomach content analysis. The stomach analysis showed an ontogenetic change in the diet composition of L. stappersii, shifting from copepods to fish larvae, supplemented with shrimp, to whole fish prey as the fish grew larger. Stable carbon and nitrogen isotope values from fish muscle were consistent with this observation, and also seemed to indicate that fish of similar sizes had similar diets, irrespective of species. This suggests that the diet of the pelagic fish species might be better explained by size, rather than species. The isotope data revealed a short range of δ¹⁵N values from primary consumers to fish, which may help explain the high fisheries productivity of Lake Tanganyika, and the strong impact of primary productivity changes on fisheries yield.