Optical mode size control by MgO indiffusion in Ti:LiNbO3 waveguides

In this paper, the use of magnesium oxide (MgO) indiffusion in combination with Ti:LiNbO<sub>3</sub> through appropriate control of pre- and post-diffusion parameters is investigated as a way of controlling optical mode size. The co-diffusion of pre-patterned Ti with various patterned MgO films on LiNbO<sub>3</sub> has been compared experimentally. This method has been applied to study straight waveguides and couplers. The waveguides were optically characterized by near-field mode size and loss measurements methods at a wavelength of 1.55 μm. Reduction of inter-mode coupling between adjacent waveguides with the introduction of MgO has been observed

Globular cluster population of the HST frontier fields galaxy J07173724+3744224

We present the first measurement of the globular cluster population surrounding the elliptical galaxy J07173724+3744224 (z=0.1546). This galaxy is located in the foreground in the field-of-view of the Hubble Space Telescope (HST) Frontier Fields observations of galaxy cluster MACS J0717.5+3745 (z=0.5458). Based on deep HST ACS F435W, F606W, and F814W images, we find a total globular cluster population of N_tot = 3441 +/- 1416. Applying the appropriate extinction correction and filter transformation from ACS F814W to the Johnson V-band, we determine that the host galaxy has an absolute magnitude of M_V = -22.2. The specific frequency was found to be S_N = 4.5 +/- 1.8. The radial profile of the globular cluster system was best fit using a powerlaw of the form $\sigma\sim R^{-0.6}$, with the globular cluster population found to be more extended than the halo light of the host galaxy ($\sigma_{halo}\sim R^{-1.7}$). The F435W-F814W colour distribution suggests a bimodal population, with red globular clusters 1-3x more abundant than blue clusters. These results are consistent with the host elliptical galaxy J07173724+3744224 having formed its red metal-rich GCs in situ, with the blue metal-poor globular clusters accreted from low-mass galaxies.Comment: 21 pages, 14 figures, 2 tables, revised following peer-review, accepted for publication in MNRA

An irrigated area map of the world (1999) derived from remote sensing

Remote sensing / Mapping / GIS / Irrigated sites / Estimation

Influence of Biochar on Plant Uptake of Personal Care Products: Caffeine and Triclosan

The use of personal care products (PCPs) extends a person's longevity. Nonetheless, because of its uncontrolled burden on the environment, it is regarded as an emerging contaminant. The goal of this research is to determine the influence of cinnamon wood biochar (CWBC) on plant uptake of caffeine (CFN) and triclosan (TRI) from the soil. Ipomeoa aquatica was cultivated for 4 weeks in soil with a 2.5% CWBC amendment and spiked with 100 mg/kg CFN and 200 mg/kg TRI. Ultra- High-performance liquid chromatography (UHPLC) was used to quantify the CFN and TRI in the plant. The surface morphology of CWBC was investigated by scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) surface area. The gasification of biomass which increased the CWBC's surface area to 589 m2/g, due to the development of a porous structure. The CFN accumulated more in the shoot of the plant whereas TRI accumulated in the root. The addition of 2.5% CWBC significantly (p<0.05) decreased the root and shoot accumulation of CFN by 40.4% and 70.9%, whilst those for TRI by 38.9% and 19.9%, respectively. The relative bioconcentration factors (RBF) of CFN and TRI in shoot and root was calculated by the ratio of bioconcentration factor (BCF) using RBF=〖BCF(CWBC amended soil)⁄〖BCF_soil and the results suggested that the addition of 2.5% CWBC decrease the RBF below the one indicating the effectiveness of CWBC towards mitigating the plant uptake of PCPs. Overall, the present study suggested the application of biochar to soil significantly decreased the plant uptake of PCPs, thus, can reduce the potential risk caused by the unintentional consumption of contaminated vegetables.  Keywords: Personal Care Products, Soil amendment, Health risk, Plant uptake&nbsp

Visible Light Communication Using a Blue GaN μLED and Fluorescent Polymer Color Converter

This letter presents a novel technique to achieve high-speed visible light communication (VLC) using white light generated by a blue GaN mu LED and a yellow fluorescent copolymer. We generated white light suitable for room illumination by optimizing the ratio between the blue electroluminescence of the mu LED and yellow photoluminescence of the copolymer color converter. Taking advantage of the components' high bandwidth, we demonstrated 1.68 Gb/s at a distance of 3 cm (at 240 lx illumination). To the best of our knowledge, this is the fastest white light VLC results using a single blue LED/color converter combination.PostprintPeer reviewe

Long-term assessment of surface water quality in a highly managed estuary basin

Anthropogenic developments in coastal watersheds cause significant ecological changes to estuaries. Since estuaries respond to inputs on relatively long time scales, robust analyses of long-term data should be employed to account for seasonality, internal cycling, and climatological cycles. This study characterizes the water quality of a highly managed coastal basin, the St. Lucie Estuary Basin, FL, USA, from 1999 to 2019 to detect spatiotemporal differences in the estuary’s water quality and its tributaries. The estuary is artificially connected to Lake Okeechobee, so it receives fresh water from an external basin. Monthly water samples collected from November 1999 to October 2019 were assessed using principal component analysis, correlation analysis, and the Seasonal Kendall trend test. Nitrogen, phosphorus, color, total suspended solids, and turbidity concentrations varied sea-sonally and spatially. Inflows from Lake Okeechobee were characterized by high turbidity, while higher phosphorus concentrations characterized inflows from tributaries within the basin. Differences among tributaries within the basin may be attributed to flow regimes (e.g., significant releases vs. steady flow) and land use (e.g., pasture vs. row crops). Decreasing trends for orthophosphate, total phosphorus, and color and increasing trends for dissolved oxygen were found over the long term. Decreases in nutrient concentrations over time could be due to local mitigation efforts. Understanding the differences in water quality between the tributaries of the St. Lucie Estuary is es-sential for the overall water quality management of the estuary

Anammox Process for Removal of Ammonia from Landfill Leachate

Landfilling is a common practice used to dispose municipal solid waste due to economic considerations in developing countries as Sri Lanka. Among the different ways of landfilling, open pit dumping can be identified as the worst case which creates severe impacts on environment. Major impact which was reported over the years is the contamination of ground and surface water. This highly contaminated waste water which comes through landfills, are called landfill leachate. Since, leachate is directly unveiled to the environment, proper treatment should be carried out prior to dispose. Composition of leachate varies with time. Testing of this research based on Karadiyana Dump site, Sri Lanka and it is recorded that contamination of water in terms of ammonia, nitrite and phosphorous as 700-900 mg/L, 60-126 mg/L and 33-66 mg/L respectively. Also, in Karadiyana high LPI value of 28.88 was indicated. Conventional as well as innovative treatment methods are used to treat leachate. In recent past, many innovative techniques were discovered by scientists to treat leachate. Anammox process is one of the major findings to treat high nitrogen loaded wastewater. Conventional nitrification requires high aeration and dentrification requires high carbon sources. Hence, conventional techniques incurred higher cost. Reduction of oxygen consumption by 60% and no additional carbon source requirement can be identified as dominant advantages over conventional nitrification/denitrification process comparing with anammox process. Anammox bacteria were enriched by applying synthetic wastewater under anaerobic condition in a sequencing batch reactor (SBR). After successful enrichment of anammox bacteria, reactor was set to 32+0.5o C and pH 7.5 with HRT of 4 days for anammox process. After a successful anammox process that partially treated wastewater was set to flow through bio char barricades and thereafter through a constructed wetland. 99% ammonia removal as well as 98% of nitrite removal was identified during 25 days of testing period. Further, 82% of prosperous removal also was recorded. Addition to those, 65% of COD removal was obtained. Additional development can be done to anammox process since nitrite is an intermediate component for both nitrifiction and denitrification. This partial nitritation (PN) prior to anammox treatment can be performed in a Single reactor for High activity Ammonia Removal Over Nitrite (SHARON). Main objective of PN is to achieve stoichiometric ratio between ammonia nitrogen to nitrite nitrogen for better anammox process. According to the anammox reaction this ratio should be 1:1.32 between ammonium nitrogen to nitrite nitrogen under aerobic condition and ammonium oxidizing bacteria (AOB) have to be prepared prior to the process. Sludge taken from an aeration tank can be used to enrich AOB. And this combined process is called PN-Anammox.Keywords: Anammox, Leachate treatment, Partial nitratio

Removal of Ciprofloxacin from Aqueous Media Using Dendro Biochar

Ciprofloxacin (CPX) is an emerging contaminant concern; hence this study is aimed to investigate the potential of bioenergy plant derived biochars (Dendro) (Produced from plants available in Embilipitiya (EBC), Mahiyanganaya (MBC), and Thirappane (TBC)) in the mitigation of CPX from the aqueous medium. The physiochemical properties of the biochar were characterized by the proximate analysis and Fourier Transform Infra-Red Spectroscopy (FTIR). Batch adsorption studies were conducted to study the effect of pH (2-9), contact time (0-2,880 minutes), and initial concentration (5-100 mgL-1). The maximum adsorption of CPX onto three biochar samples was facilitated around pH values of 6.5 and 7. Experimental kinetic data were best fitted with pseudo second order (R2=0.846) for MBC while Elovich model described the kinetics for EBC (R2=0.923) and TBC (R2=0.854) in aqueous medium. Isotherm data for aqueous medium were well described by the Langmuir model for EBC (R2=0.936), Freundlich model for MBC (R2=0.985), and Temkin model for TBC (R2=0.985). Obtained data confirmed that EBC followed chemisorption and physisorption interactions meanwhile MBC and TBC showed physisorption interactions. EBC reported the highest maximum adsorption capacity value as high temperature produced biochar exhibits greater potential in the removal of organic contaminants. Distribution coefficient values calculated for three biochar samples showed a positive correlation with adsorption in aqueous medium. Furthermore, colloids were fabricated to study the adsorption with varying pH in comparison with the pristine form. According to the studies, colloidal form of TBC and MBC showed significant adsorption compared to EBC with its pristine form as the ball milling may have increased the surface area which aids in the adsorption. FTIR data suggested the presence of hydroxyl groups, aromatic nature on the surface of the biochar. Isotherm studies conducted using synthetic hydrolysed urine matrix using MBC and MBC colloids suggested a chemisorption mechanism dominated in the adsorption of CPX onto biochar in competitive ions. Thus, these outcomes imply that bioenergy plant derived biochar can be utilized as a potential low-cost, sustainable adsorbent in mitigating emerging contaminants such as CPX from the environment.   Keywords: Carbon materials, Emerging contaminants, Antibiotics, Adsorptio

Municipal solid waste biochar-bentonite composite for the removal of antibiotic ciprofloxacin from aqueous media

This study investigates the adsorption of ciprofloxacin (CPX) onto a municipal solid waste derived biochar (MSW-BC) and a composite material developed by combining the biochar with bentonite clay. A bentonite-MSW slurry was first prepared at 1:5 ratio (w/w), and then pyrolyzed at 450 °C for 30 min. The composite was characterized by scanning electron microscopy (SEM), Powder X-ray diffraction (PXRD) and Fourier transform infrared (FTIR) spectroscopy before and after CPX adsorption. Batch experiments were conducted to assess the effect of pH, reaction time and adsorbate dosage. The SEM images confirmed successful modification of the biochar with bentonite showing plate like structures. The PXRD patterns showed changes in the crystalline lattice of both MSW-BC and the composite before and after CPX adsorption whereas the FTIR spectra indicated merging and widening of specific bands after CPX adsorption. The optimum CPX adsorption was achieved at pH 6, and the maximum adsorption capacity of the composite calculated via isotherm modeling was 190 mg/g, which was about 40% higher than the pristine MSW-BC. The Hill isotherm model along with pseudo-second order and Elovich kinetic models showed the best fit to the adsorption data. The most plausible mechanism for increased adsorption capacity is the increased active sites of the composites for CPX adsorption through induced electrostatic interactions between the functional groups of the composite and CPX molecules. The added reactive surfaces in the composite because of bentonite incorporation, and the intercalation of CPX in the clay interlayers improved the adsorption of CPX by the biochar-bentonite composite compared to the pristine biochar. Thus, MSW-BC-bentonite composites could be considered as a potential material for remediating pharmaceuticals in aqueous media