Investigation of ultrafast laser photonic material interactions: challenges for directly written glass photonics

Currently, direct-write waveguide fabrication is probably the most widely studied application of femtosecond laser micromachining in transparent dielectrics. Devices such as buried waveguides, power splitters, couplers, gratings and optical amplifiers have all been demonstrated. Waveguide properties depend critically on the sample material properties and writing laser characteristics. In this paper we discuss the challenges facing researchers using the femtosecond laser direct-write technique with specific emphasis being placed on the suitability of fused silica and phosphate glass as device hosts for different applications.Comment: 11 pages, 87 references, 11 figures. Article in revie

Lifecycle Assessment of Microalgae to Biofuel: Thermochemical Processing through Hydrothermal Liquefaction or Pyrolysis

Microalgae have many desirable attributes as a renewable energy recourse. These include use of poor quality land, high yields, and it is not a food recourse. This research focusses on the energetic and environmental impact of processing microalgae into a renewable diesel. Two thermochemical bio-oil recovery processes are analyzed, pyrolysis and hydrothermal liquefaction (HTL). System boundaries include microalgae growth, dewatering, thermochemical bio-oil recovery, bio-oil stabilization, conversion to renewable diesel, and transportation to the pump. Two system models were developed, a small-scale experimental and an industrial-scale. The small-scale system model is based on experimental data and literature. The industrial-scale system model leverages the small scale system model with scaling and optimization to represent an industrial-scaled process. The HTL and pyrolysis pathways were evaluated based on net energy ratio (NER), defined here as energy consumed over energy produced, and global warming potential (GWP). NER results for biofuel production through the industrial-scaled HTL pathway were determined to be 1.23 with corresponding greenhouse gas (GHG) emissions of -11.4 g CO2 eq (MJ renewable diesel)-1. Biofuel production through the industrial-scaled pyrolysis pathway gives a NER of 2.27 and GHG emissions of 210 g CO2 eq (MJ renewable diesel)-1. For reference, conventional diesel has an NER of 0.2 and GHG emissions of 18.9 g CO2 eq MJ-1 with a similar system boundary. The large NER and GHG emissions associated with the pyrolysis pathway are attributed to feedstock drying requirements and combustion of co-products to improve system energetics. Process energetics with HTL and pyrolysis are not currently favorable for an industrial scaled system. However, processing of microalgae to biofuel with bio-oil recovery through HTL does produce a favorable environmental impact and a NER which is close to the breakeven point of one

Mission possible: diatoms can be used to infer past duckweed (lemnoid Araceae) dominance in ponds

Compared to larger lakes, ponds have rarely been the focus of palaeoecological studies. A common feature of ponds, especially those subject to eutrophication, is mass surface coverings of lemnoid Araceae (duckweed) which have severe implications for ecological processes in small waterbodies, in particular lowered oxygen content. To help understand the implications of duckweed dominance for the long-term ecology of ponds, and to determine the potential for palaeoecological studies in ponds more generally, we develop a new diatom-based Lemna-indicator metric. Recent studies of diatom host-plant relationships have shown significant associations between duckweed and the epiphytes Lemnicola hungarica and Sellaphora saugerresii (formally known as Sellaphora seminulum). To determine the potential of these species as palaeo-indicators of long-term duckweed dynamics in ponds, we investigated the diatom composition of surface sediment assemblages in sets of duckweed and non-duckweed-dominated ponds in Norfolk, eastern England. In addition, we undertook diatom analysis of two cores from a small farmland pond (Bodham Rail Pit) subject to a known duckweed dominance event (1999–2005). Both L. hungarica and S. saugerresii were significant predictors of past Lemna dominance in the surface sediments. Further, in the core study, both diatom species accurately and closely tracked the documented “on–off” duckweed cycle. Our study suggests huge potential for using ponds in palaeoecological studies and for diatom-based investigations of floating plant histories

Liquid core fibre Bragg grating based refractive index sensor formed by femtosecond assisted chemical etching technique

We report the fabrication of a refractive index (RI) sensor based on a liquid core fibre Bragg grating (FBG). A micro-slot FBG was created in standard telecom optical fibre employing the tightly focused femtosecond laser inscription aided chemical etching. A micro-slot with dimensions of 5.74(h) × 125(w) × 1388.72(l) μm was engraved across the whole fibre and along 1mm long FBG which gives advantage of a relatively robust liquid core waveguide. The device performed the refractive index sensitivity up to about 742.72 nm/RIU

Palaeoecological study of South Milton Ley, South Devon

1. Attend South Milton Ley and obtain 6 sediment cores from 3 different areas of the ley to investigate the impact of discharges from the sewage treatment works (STW). 2. From each of the 3 locations, extrude one master core at appropriate intervals and describe its stratigraphy. 3. From each of the 3 locations, measure the dry weight and organic matter content of selected levels of the master core. 4. Date the master core from each of the 3 locations to provide a chronology of the ley sediments using radiometric dating methods and/or spheroidal carbonaceous particles (SCPs). 5. Analyse the diatom assemblages in five to ten samples from selected depths of each master core. 6. Apply a diatom-phosphorus transfer function to the diatom assemblages of each master core to reconstruct total phosphorus concentrations and in turn determine the nutrient loading history of the ley. 7. Produce a summary report of the findings

The Energy Expenditure of Recreational Ballroom Dance

International Journal of Exercise Science 7(3) : 228-235, 2014. The popularity of recreational ballroom dancing has increased dramatically in recent years. Yet, relatively little information is known regarding the physiological demands of ballroom dancing. The purpose of this study was to determine the energy requirements for recreational ballroom dancing. 24 participants volunteered including 12 women (mean ± SD: 21 ± 3 yrs, 165.8 ± 7.4 cm, 56.8 ± 11.1 kg) and 12 men (23 ± 1 yr, 175.5 ± 8.4 cm, 78.1 ± 15.6 kg). Gas exchange was recorded using a portable metabolic system during a series of five ballroom dances: Waltz, Foxtrot, Swing, Cha-Cha, and Swing. Each song was four minutes in duration, separated by a two minute rest period, totaling 30 minutes of testing. The intensity of each dance in metabolic equivalents (METs) is: Waltz = 5.3 ± 1.3, Foxtrot = 5.3 ± 1.5, Cha-Cha = 6.4 ± 1.6 and Swing = 7.1 ± 1.6 and 6.9 ± 1.7. Mean energy cost for the 30 minutes of testing was 5.88 ±1.7 kilocalories (kcal•min-1), 6.12 ± 1.2 METs. Mean energy cost and months of recreational dance experience were not significantly related (R2 = 0.04, p = 0.35). Energy expenditure of the follow partner was significantly related to the energy expenditure of the lead partner (R2 = 0.52, p \u3c0.01). Finally, this study validates the intensity of recreational ballroom dance as matching the criteria established by the American College of Sports Medicine for improving cardiorespiratory fitness and reducing the risk of chronic diseases

Using a task-based approach in evaluating the usability of BoBIs in an e-book environment

This paper reports on a usability evaluation of BoBIs (Back-of-the-book Indexes) as searching and browsing tools in an e-book environment. This study employed a task-based approach and within-subject design. The retrieval performance of a BoBI was compared with a ToC and Full-Text Search tool in terms of their respective effectiveness and efficiency for finding information in e-books. The results demonstrated that a BoBI was significantly more efficient (faster) and useful compared to a ToC or Full-Text Search tool for finding information in an e-book environment

Fabrication of highly efficient grating band-pass filters and their applications in soliton propagation system

We report here fabrication of highly efficient in-fiber grating bandpass filters using the established UV-side- exposure technique. Various combinations of passband/stopband and transmission/rejection of single- and multi-channel filters have been produced in hydrogenated standard telecom, high Ge-doped and B/Ge-codoped fibers. Up to > 60 dB rejection stopbands ranging from -2 nm to 55 nm, and passbands with 0.02 nm - 3 nm linewidths and transmissivity up to > 90% have been achieved with these devices. By concatenating several structures, a bandpass filter has been demonstrated with a combination of a 0.16 nm passband centered in a approximately 35 nm stopband, representing the highest reported finesse of 220 for any multi-nanometer stopband filter. We also report the first application of a grating bandpass filter for suppressing timing jitter in soliton propagation system, enabling transmission of 10 ps solitons over a distance of 2700 km

Discovery of Bisamide-heterocycles as Inhibitors of Scavenger Receptor BI (SR-BI)-mediated Lipid Uptake

A new series of potent inhibitors of cellular lipid uptake from HDL particles mediated by scavenger receptor, class B, type I (SR-BI) was identified. The series was identified via a high-throughput screen of the National Institutes of Health Molecular Libraries Small Molecule Repository (NIH MLSMR) that measured the transfer of the fluorescent lipid DiI from HDL particles to CHO cells overexpressing SR-BI. The series is characterized by a linear peptidomimetic scaffold with two adjacent amide groups, as well as an aryl-substituted heterocycle. Analogs of the initial hit were rapidly prepared via Ugi 4-component reaction, and select enantiopure compounds were prepared via a stepwise sequence. Structure–activity relationship (SAR) studies suggest an oxygenated arene is preferred at the western end of the molecule, as well as highly lipophilic substituents on the central and eastern nitrogens. Compound 5e, with (R)-stereochemistry at the central carbon, was designated as probe ML279. Mechanistic studies indicate that ML279 stabilizes the interaction of HDL particles with SR-BI, and its effect is reversible. It shows good potency (IC50 = 17 nM), is non-toxic, plasma stable, and has improved solubility over our alternative probe ML278

Modelling phosphorus fluxes in Loweswater

1. This is the final report to the Loweswater Care Project (in support of the Catchment Restoration Fund for England) ECRC-ENSIS Project 298, 'Loweswater 12-13'. The study was concerned with the spatial and temporal concentrations of sediment phosphorus (P) in the lake and the use of P measurements from the water column and inflow and outflow samples to derive a simple mass balance model for P in the lake. 2. A review of published and unpublished literature on Loweswater highlighted trends in water chemistry since the mid-eighteenth century. Land use and farming practises have changed over the past 200 years which have led to increased nutrient loading to the lake with significant increases occurring in the mid part of the last century. Agricultural intensification is likely to be a significant cause of the problem as well as inadequate septic tank management. Local management efforts, led by the Loweswater Care Project, has sought to reduce the primary sources of nutrients reaching the lake, but total phosphorus (TP) concentrations in the lake remain higher than desired. 3. Temperature and dissolved oxygen (DO) profiling confirmed that the site stratified in summer with major changes in DO occurring below a depth of 8 m. The deeper waters were almost entirely anoxic. During stratification the maximum TP value was recorded at the lake bottom. This is a clear indication that P is being released from the lake bed during summer stratification. 4. Analysis of the stream water from the Dub Beck inflow (data for 2013), shows that P influx remains high enough to explain the elevated lake water P concentrations, despite considerable efforts to reduce catchment P sources. 5. Analysis of the water column P profiles shows that P release from the sediment is only a minor contribution to the P load. While the sediment core data reveals a substantial pool of P in the sediment very little of this should be released each year to the water column. In 2013 it is estimated that more than 90% of the P came from the catchment and only ~10% from the sediment. 6. As with all modelling exercises there are uncertainties inherent in the approach. In this case the model output is based on a single year of input data for the inflow P flux calculations and it would be preferable to have a longer data series to inform the modelling. Inflow fluxes are highly dependent on flow conditions and here, in the absence of flow data from Dub Beck, we used data from a nearby stream. Further, the monthly sampling has resulted in most samples being taken in low flow conditions, thus missing potential storm flow conditions. Finally, stream input information is restricted to Dub Beck, and contributions from the other stream is unknown. 7. Nevertheless, the results from the modelling are clear and on that basis we conclude that the priority is for P loading to the lake to be reduced by better catchment management and that lake manipulation is not warranted. Integrated catchment management supported by modelling together with local stakeholder engagement should provide the most effective means of improving the condition of the lake