Performance analysis of reverse osmosis, membrane distillation, and pressure-retarded osmosis hybrid processes

© 2015 Elsevier B.V. A performance analysis of a tri-combined process that consists of reverse osmosis (RO), membrane distillation (MD), and pressure-retarded osmosis (PRO) was conducted by using numerical approaches in order to evaluate its feasibility. In the hybrid process, the RO brine is partially used as the MD feed solution, and the concentrated MD brine is then mixed with the rest of the RO brine to be considered as the PRO draw solution. Here, the brine division ratio, incoming flow rate of RO, dimensions of the MD and PRO processes, and the supply cost of the MD heat source were considered as influential parameters. Previously validated process models were employed and the specific energy consumption (SEC) was calculated to examine the performance of the RO-MD-PRO hybrid process. The simulation results confirmed that the RO-MD-PRO hybrid process could outperform stand-alone RO in terms of reducing the SEC and the environmental footprint by dilution of the RO brine in locations where free or low-cost thermal energy can be exploited. Despite the need for further investigations and pilot-tests to determine its commercial practicability, this study provides insights into future directions for water and energy nexus processes for energy efficient desalination

Lower bounds for on-line graph colorings

We propose two strategies for Presenter in on-line graph coloring games. The first one constructs bipartite graphs and forces any on-line coloring algorithm to use $2\log_2 n - 10$ colors, where $n$ is the number of vertices in the constructed graph. This is best possible up to an additive constant. The second strategy constructs graphs that contain neither $C_3$ nor $C_5$ as a subgraph and forces $\Omega(\frac{n}{\log n}^\frac{1}{3})$ colors. The best known on-line coloring algorithm for these graphs uses $O(n^{\frac{1}{2}})$ colors

Magnetised titanium dioxide (TiO2) for water purification: preparation, characterisation and application

© 2014 Balaban Desalination Publications. All rights reserved. The study of titanium dioxide (TiO2) as a photocatalyst for water purification has attracted significant attention over the past four decades. However, the separation of photocatalyst from water suspension may be difficult, costly and jeopardise the use of this water treatment technology. Recently, the development and production of magnetised TiO2 have been achieved to offer a solution for the photocatalyst separation problem. This paper discusses the preparation techniques, characterisation and the applications of magnetised TiO2. Many researchers have studied magnetised TiO2 photocatalysts but the lack of articles discussing the water purification processes is still slowing any advance in this field. Here, the progress of the scientific research on preparation techniques to coat magnetic particles by materials such as organic polymers, silica, magnesia, and alumina are reviewed to compare and discuss recent findings. The doping of photoactive TiO2 photocatalyst into the magnetic-coated particles is also emphasised. In addition, the characterisation of magnetised TiO2 in terms of physicochemical properties and operating conditions produced by each technique are critically reviewed. Moreover, examples of applications of TiO2 and magnetised TiO2 photocatalyst in water purification are summarised. In general, the effectiveness of organic removal by magnetised TiO2 is still lower compared to single phase TiO2. The future prospect of this field is deliberated to develop a novel, economic and efficient magnetised TiO2 photocatalyst, which has high organic removal properties

On graphs with a large chromatic number containing no small odd cycles

In this paper, we present the lower bounds for the number of vertices in a graph with a large chromatic number containing no small odd cycles

Variation of structural, electrical, and optical properties of Zn <inf>1-x</inf>Mg <inf>x</inf>O thin films

Zn 1-xMg xO thin films on (001) sapphire substrates were deposited using pulsed laser deposition. As the substrate temperature increased, the Mg content in the Zn 1-xMg xO thin films increased and the photoluminescence (PL) peak position of the Zn 1-xMg xO thin films shifted from 370 to 356 nm, indicating a band gap expansion. Variations of the structural, electrical, and optical properties of Zn 1-xMgO thin films have been observed and analyzed by x-ray diffraction, Hall measurements, and PL measurements. © 2006 American Institute of Physics

Reduction in CO2 uptake rates of red tide dinoflagellates due to mixotrophy

We investigated a possible reduction in CO2 uptake rate by phototrophic red tide dinoflagellates arising from mixotrophy. We measured the daily ingestion rates of Prorocentrum minimum by Prorocentrum micans over 5 days in 10 L experimentalbottles, and the uptake rates of total dissolved inorganic carbon (CT) by a mixture of P. micans and P. minimum(mixotrophic growth), and for the predator P. micans (phototrophic growth; control) and prey P. minimum (phototrophicgrowth; control) alone. To account for the effect of pH on the phototrophic growth rates of P. micans and P. minimum,measurements of CT and pH in the predator and prey control bottles were continued until the pH reached the same level(pH 9.5) as that in the experimental bottles on the final day of incubation. The measured total CT uptake rate by the mixtureof P. micans and P. minimum changed from 123 to 161 μmol CT kg-1 d-1 over the course of the experiment, and waslower than the CT uptake rates shown by P. micans and P. minimum in the predator and prey control bottles, respectively,which changed from 132 to 176 μmol CT kg-1 d-1 over the course of the experiment. The reduction in total CT uptake ratearising from the mixotrophy of P. micans was 7-31% of the daily CT uptake rate seen during photosynthesis. The resultssuggest that red tide dinoflagellates take up less CT during mixotrophy.1131Ysciescopuskc

The hot and cold interstellar matter of early type galaxies and their radio emission

Over the last few years, the knowledge of the interstellar matter (ISM) of early type galaxies has increased dramatically. Many early type galaxies are now known to have ISM in three different phases: cold (neutral hydrogen (HI), dust and molecular material), warm (ionized) and hot (S-ray emitting) gas. Early type galaxies have smaller masses of cold ISM (10 to the 7th power - 10 to the 8th power solar mass; Jura et al. 1987) than later type spiral galaxies, while they have far more hot gas (10 to the 9th power - 10 to the tenth power solar mass; Forman et al. 1985, Canizares et al. 1987). In order to understand the relationship between the different phases of the ISM and the role of the ISM in fueling radio continuum sources and star formation, researchers compared observational data from a wide range of wavelengths

Photodesorption of specific organic compounds from titanium dioxide particles in aqueous media

This study investigates the photodesorption of organic compounds (beef extract, peptone, humic acid, tannic acid, sodium lignin sulphonate, sodium lauryl sulphate, arabic gum powder and arabic acid) from TiO2 (1 g/L in water, pH 7). After a period to reach adsorption equilibrium, photodesorption experiments were conducted in a recirculated reactor at a constant flow rate of 150 mL/min with a UV light intensity of 24 W. Photodesorption was observed only for sodium lauryl sulphate (50%), sodium lignin sulphonate (43.47%), beef extract (20.35%) and tannic acid (10.5%) indicating that photodesorption is specific to some organic compounds but not to all. Using liquid chromatography-organic carbon detection, untreated beef extract and sodium lignin sulphonate were found to contain significant amounts of humic substances (∼1,000 g/mol), which decreased in concentration after dark phase adsorption, while a significant increase in low molecular weight (<350 g/mol) concentrations was observed after photodesorption. UV-treated sodium lauryl sulphate photodesorbed to give both higher molecular weight (HMW) and lower molecular weight (LMW) organics. Thus, the HMW fractions of organic compounds decomposed into smaller compounds after UV irradiation, which subsequently desorbed from TiO2 surface. However, untreated tannic acid contained a larger proportion of LMW acids, which shows a high adsorption affinity to TiO2 during adsorption and poorly desorbs upon irradiation. © 2013 © 2013 Balaban Desalination Publications. All rights reserved

Inhibitory Activity of Bevacizumab to Differentiation of Retinoblastoma Cells

Vascular endothelial growth factor (VEGF) is a major regulator in retinal and choroidal angiogenesis, which are common causes of blindness in all age groups. Recently anti-VEGF treatment using anti-VEGF antibody has revolutionarily improved the visual outcome in patients with vaso-proliferative retinopathies. Herein, we demonstrated that bevacizumab as an anti-VEGF antibody could inhibit differentiation of retinoblastoma cells without affection to cellular viability, which would be mediated via blockade of extracellular signal-regulated kinase (ERK) 1/2 activation. The retinoblastoma cells expressed VEGFR-2 as well as TrkA which is a neurotrophin receptor associated with differentiation of retinoblastoma cells. TrkA in retinoblastoma cells was activated with VEGF treatment. Interestingly even in the concentration of no cellular death, bevascizumab significantly attenuated the neurite formation of differentiated retinoblastoma cells, which was accompanied by inhibition of neurofilament and shank2 expression. Furthermore, bevacizumab inhibited differentiation of retinoblastoma cells by blockade of ERK 1/2 activation. Therefore, based on that the differentiated retinoblastoma cells are mostly photoreceptors, our results suggest that anti-VEGF therapies would affect to the maintenance or function of photoreceptors in mature retina

Diameter-selective separation of double-walled carbon nanotubes

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in APPLIED PHYSICS LETTERS. 93(22):223107 (2008) and may be found at https://doi.org/10.1063/1.3039790 .ArticleAPPLIED PHYSICS LETTERS. 93(22):223107 (2008)journal articl