86 research outputs found

    Effect of Chloride Exposure Condition on the Performance of Concretes Containing Pfa

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    Over the past number of decades the use of different supplementary cementing materials have been investigated, with a view to increasing the resilience of reinforced concrete to chloride-induced corrosion. The slow nature of chloride-ion ingress has meant much of the information available on the relative performance of different concretes has been derived from accelerated testing, with the majority of these tests conducted under fully saturated conditions. While there is merit to such practices, there is also a need to examine the relative performance of different concretes under unsaturated conditions. This need is highlighted by the fact that reinforced concrete elements in the splash, spray and tidal zones of marine structures, which are subject to wetting and drying cycles, are most susceptible to reinforcement corrosion. This paper examines the effect of different wetting and drying cycles on the relative performance of OPC self-compacting concrete, and self-compacting concrete containing PFA. This was achieved through three sets of salt fog chamber tests, each with different wetting and drying cycles. It was found that, when compared to the OPC option, the relative chloride ingress resistance of the OPC + PFA concrete reduced when the degree of drying in the test increased. This indicates that fully saturated tests may somewhat overestimate the practical benefits of incorporating PFA into concrete in chloride rich environments

    Assessing the Benefits of Compressed Air Energy Storage on the 2020 Irish Power System

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    Power systems have evolved as countries implement energy policies focusing on energy efficiency and increased share of renewable energy sources (RES). At the forefront is non-dispatchable generation such as wind and solar. Traditionally power systems were designed for fully dispatchable generating plant. However, these powers systems are under additional pressure due to the variable operational characteristics of RES. Consequently, capital investments in grid reinforcement, interconnection, additional gas generators and smart grid initiatives have been proposed and implemented. Moreover, an increased interest in energy storage technologies has evolved due to their various economic and operational benefits to power systems. Current compressed air energy storage (CAES) plants have shown economic feasibility and reliability. Thus, the main focus of this paper is to investigate and compare two scenarios; one without CAES and a second with CAES as an additional generator in the 2020 Irish power system using power systems simulation software PLEXOS

    Non-Indigenous Bamboo along Headwater Streams of the Luquillo Mountains, Puerto Rico: Leaf Fall, Aquatic Leaf Decay and Patterns of Invasion

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    The introduction of bamboo to montane rain forests of the Luquillo Mountains, Puerto Rico in the 1930s and 1940s has led to present-day bamboo monocultures in numerous riparian areas. When a non-native species invades a riparian ecosystem, in-stream detritivores can be affected. Bamboo dynamics expected to influence stream communities in the Luquillo Experimental Forest (LEF) were examined. Based on current distributions, bamboo has spread downstream at a rate of 8 m y -1 . Mean growth rate of bamboo culms was 15.3 cm d -1 . Leaf fall from bamboo stands exceeded that of native mixed-species forest by c. 30(k = -0.021), and leaves from another abundant riparian exotic, Syzygium jambos (Myrtaceae) (k = -0.018), decayed at relatively slow rates when submerged in streams in fine-mesh bags which excluded macro-invertebrate leaf processors. In a second study, with leaf processors present, bamboo decay rates remained unchanged (k = -0.021), while decay rates of S. jambos increased (k = -0.037). Elemental losses from bamboo leaves in streams were rapid, further suggesting a change in riparian zone/stream dynamics following bamboo invasion. As non-indigenous bamboos spread along Puerto Rico streams, they are likely to alter aquatic communities dependent on leaf input

    In Vitro Evaluation of the Cytotoxicity of a Folate-modified β-cyclodextrin as a New Anti-cancer Drug Delivery System

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    Many chemotherapeutic drugs are therapeutically non-selective and do not distinguish between healthy cells and tumour cells which can result in severe side effects and toxicity. Drug delivery systems can be used to target specific cells and therefore may eliminate many of the side effects, increasing drug efficiency and efficacy, and controlling drug release. One possible strategy for targeted drug delivery is to use unique molecular markers such as folate receptors in cancer cells. In this work the cytotoxicity of a novel cyclodextrin-folate conjugate, 6-deoxy-6-[(1-(-2amino)ethylamino)folate-β-cyclodextrin (CDEnFA) was studied using the MTT assay and the MCF-7 (Breast), HeLa (Cervical), A549 (Lung cancer) and BEAS-2B (normal Lung) cell lines. The MTT assay showed that the drug delivery vehicle CDEnFA is not cytotoxic towards the cell lines studied even towards the normal BEAS-2B cell line and therefore it is expected that it is safe for medical use. The inclusion complex CDEnFA:MTX has superior cytotoxic activity towards all of the cancer cell lines studied compared to the drug MTX alone and CDEnFA:MTX is four times less cytotoxic than the drug towards the normal cell line. The observed toxicity is attributed solely to MTX since CDEnFA did not exhibit significant cytotoxicity. These results also suggest that the drug remains bioactive even after inclusion in the CD cavity. The cytotoxicity trend observed for CDEnFA:MTX in this study is MCF-7 (Breast) \u3e A549 (Lung) \u3e HeLa (Cervical) \u3e BEAS-2B (normal Lung)

    Sensor node localisation using a stereo camera rig

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    In this paper, we use stereo vision processing techniques to detect and localise sensors used for monitoring simulated environmental events within an experimental sensor network testbed. Our sensor nodes communicate to the camera through patterns emitted by light emitting diodes (LEDs). Ultimately, we envisage the use of very low-cost, low-power, compact microcontroller-based sensing nodes that employ LED communication rather than power hungry RF to transmit data that is gathered via existing CCTV infrastructure. To facilitate our research, we have constructed a controlled environment where nodes and cameras can be deployed and potentially hazardous chemical or physical plumes can be introduced to simulate environmental pollution events in a controlled manner. In this paper we show how 3D spatial localisation of sensors becomes a straightforward task when a stereo camera rig is used rather than a more usual 2D CCTV camera

    Estimating the Electricity Prices, Generation Costs and CO2 Emissions of Large Scale Wind Energy Exports from Ireland to Great Britain

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    The share of wind generation in the Irish and British electricity markets is set to increase by 2020 due to renewable energy (RE) targets. The United Kingdom (UK) and Ireland have set ambitious targets which require 30% and 40% of electricity demand to come from RE, mainly wind, by 2020, respectively. Ireland has sufficient indigenous onshore wind energy resources to exceed the RE target, while the UK faces uncertainty in achieving its target. A possible solution for the UK is to import RE directly from large scale onshore and offshore wind energy projects in Ireland; this possibility has recently been explored by both governments but is currently on hold. Thus, the aim of this paper is to estimate the effects of large scale wind energy in the Irish and British electricity markets in terms of wholesale system marginal prices, total generation costs and CO2 emissions. The results indicate when the large scale Irish-based wind energy projects are connected directly to the UK there is a decrease of 0.6% and 2% in the Irish and British wholesale system marginal prices under the UK National Grid slow progression scenario, respectively

    Three Combined Correspondences

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    A correspondence from Alan S. Madans to Justice Blackmun. A correspondence from Justice Blackmun to Justice O\u27Connor, and a reply from Justice O\u27Connor to Justice Blackmun

    Synthesis, characterisation and DNA intercalation studies of regioisomers of ruthenium (II) polypyridyl complexes

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    Regioisomers of the functional group of the main ligand (L) on a series of [Ru(phen)2L]2+and [Ru(bpy)2L]2+ complexes, where phen is 1,10 phenanthroline and bpy is 2,2′-bipyridine, were synthesised to investigate the interaction with deoxyribonucleic acid (DNA) as potential therapeutics. UV–Vis binding titrations, thermal denaturation and circular dichroism were used to evaluate their interaction with DNA. The conclusions indicated the significance of the auxiliary ligand; especially 1,10-phenanthroline has on the binding constants (Kb). The systematic variation of auxiliary ligand(phen or bpy), and polypyridyl ligand (4-(1H-Imidazo[4,5-f][1,10]phenanthrolin-2-yl)benzonitrile (CPIP), 2-(4-formylphenyl)imidazo[4,5-f] [1,10] phenanthroline (FPIP), 2-(4-bromophenyl)imidazo[4,5-f][1,10]phenanthroline (BPIP) and 2-(4-nitrophenyl)imidazo[4,5-f] [1,10] phenanthroline (NPIP), split in terms of functional group change were investigated for DNA interaction. The CPIP analogues in particular were investigated for the regioisomerism (ortho, meta, para) effect of the nitrile group on the ligand. It was found that both the DNA interaction could be tailored through the systematic variation of the electronic nature of the individual auxiliary ligand and to a lesser extent the functional group and regioisomeric change. Preliminary cell line studies have been carried out to determine the selectivity of the complexes against cell lines such as A375 (Skin Cancer), HeLa (Cervical Cancer), A549 (Lung Cancer), Beas2B (Lung Normal Cell) and MCF-7 (Breast Cancer). Complexes which had strong DNA interactions in the binding studies have proven to be the most efficacious against certain cell lines. Establishing well-defined structure property relationships when looking at trends in spectroscopic properties and DNA binding will aid in the intelligent design of potential therapeutic complexes

    Water-soluble bis(1,10-phenanthroline) Octanedioate Cu2+ and Mn2+ Complexes with Unprecedented Nano and Picomolar in Vitro Cytotoxicity: Promising Leads for Chemotherapeutic Drug Development

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    Dinuclear CuII and MnII bis-phenanthroline octanedioate complexes exhibit rapid, unprecedented nano and picomolar in vitro cytotoxicity against colorectal cancer lines and are less toxic than cisplatin when examined in vivo. The complexes are potent generators of cellular reactive oxygen species, avid DNA binders and induce O2 dependent cleavage of DNA. The Cu(II) complex was found to have self-cleaving nuclease activity
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