Suchergebnisse

Human urine is a unique solution that has the right composition to constitute both a severe environmental threat and a rich source of nitrogen and phosphorous. In fact, between 4-9% of urine mass consists of ions, such as K+, Cl-, Na+ or NH4+. Because of its high ionic strength, urine osmotic pressure can reach values of up to 2000 kPa. With this in mind, this work aimed to study the effectiveness of real urine as a novel draw solution for forward osmosis. Water flux, reverse nitrogen flux and membrane fouling were investigated using fresh or hydrolysed urine. Water flux as high as 16.7 ± 1.1 L.m-2. h-1 was recorded using real hydrolysed urine. Additionally, no support layer membrane fouling was noticed in over 20 hours of experimentation. Urine was also employed to dewater a Chlorella vulgaris culture. A fourfold increase in algal concentration was achieved while having an average flux of 14.1 L.m-2. h-1. During the algae dewatering, a flux decrease of about 19% was noticed; this was mainly due to a thin layer of algal deposition on the active side of the membrane. Overall, human urine was found to be an effective draw solution for forward osmosis. ; This research was supported by the National Research Foundation of Korean Grant funded by the Korean Government (MSIP) (No. NRF-2015R1A5A7037825) and by the Australian Research Council through Future Fellowship (FT140101208). HY and CL are grateful for the support of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) through the "Human Resources Program in Energy Technology" project (No. 20164030201010) funded by the Ministry of Trade, Industry and Energy, Republic of Korea.

AbstractThe forward osmosis (FO) desalination process has recently acknowledged a lot of attention as a promising solution for reducing the disadvantages of existing desalination systems. This work aimed to investigate the effect of a selected liquid organic fertilizer a novel draw solution produced from "microalgae Spirulina platensis" on the biofouling mechanism of FO membrane. Different draw solution (DS) concentrations ranging 240–480 g/L were examined, obtained water flux ranging from 6.5 to 3.4 Lm2h-1. A high flux decline was observed when using higher DS concentrations due to fouling layer accumulated throughout the membrane area which lowers the effective osmotic pressure difference. Different cleaning strategies were examined. The biofouled membrane was cleaned on-line with deionized water (DI) and externally using ultrasound (US) and HCl. Baseline experiments were done to investigate the efficiency of the cleaning strategies. After cleaning using the deionized water (DI) water, it was found that the water flux progressed from 3.4 to 7 Lm2h-1, while when using acid cleaning the flux recovered to 15 Lm-2h-1. The efficacy and amount of foulant removed by each cleaning stage were assessed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX).

AbstractFertilizer-drawn forward osmosis (FDFO) has received a lot of attention for its potential for producing fertigated water for agriculture purposes. To minimize the use of chemical-based fertilizers and support sustainable organic agriculture, this work investigated the separation performance of FO membrane for different feed concentrations (FS) of brackish water using microalgae Spirulina platensis as an organic fertilizer draw solution (DS). Different feed solution concentrations were investigated ranging 3–20 g/L NaCl, with various draw solutions of spirulina ranging 280–440 g/L. The performance was measured by water flux and recovery. The results showed that using spirulina as a draw solution is a promising solution for fertigation purposes. The results showed that Na+ in feed solution is concentrated by 41%, Cl- by 36%, and spirulina is diluted by 20% for feed salinity 5000 mg/L. The highest flux obtained with different feed solution 3000/5000/10,000/20,000 mg/L were 9/6/4.5/7 for draw solution concentration of 360/360/400/420 g/L. The calculated specific reverse solute flux (SRSF) JS/JW varies from 0.1 and 0.8 for different explored FS/DS concentrations. Flux decline and the down-time was investigated for the highest flux observed, showing 290 min of operation before cleaning action is required.

AbstractThis study investigated the potential of utilizing both the draw and feed solutions resulting from fertilizer drawn forward osmosis for hydroponic crop cultivation. Synthetic brackish groundwater of 2500 ppm was used as the feed solution, whereas commercial hydroponic nutrients, sourced from a local supplier, were utilized as a draw solution. This study also investigated the potential of integrating nanofiltration with forward osmosis, but supplementing the water necessary for further dilution of draw solutions through nanofiltration. Two crops were selected, i.e., cherry tomatoes and spinach grown at different water salinities, for their economic values. The cherry tomatoes were grown in Deep Water Culture hydroponic systems, while the spinach was grown in Nutrient Film Technique systems. If this application is deemed feasible, it allows for providing a method to grow two different crops in areas associated with non-arable land and brackish groundwater. During desalination, it was observed that there were two groups of flux readings, the first with an average flux of 7 to 9 l/m2/h, and the other with an average flux of 4 to 6 l/m2/h. This was due to using the same draw solution twice; once to concentrate the feed solution to 5000 ppm, and then once more to concentrate the feed solution to 3500 ppm. It was found that while the 3500 ppm cherry tomatoes tables had the highest yield and highest number of tomatoes throughout the plants lifetime, tomatoes from freshwater tables on average weighed more by about 19%, while, on average, 5000 ppm tomatoes weighed less than 3500 ppm tomatoes by 10%. The results of the spinach demonstrated that while both control and experiment groups yielded similar number of leaves, the average yield per plant for the experiment group was higher than the control group (by 25%).

There are currently dozens of conceptions in democratic theory of what constitutes democratic progress and even more concepts of the crisis of democracy. This plethora of ideas is both good news and bad news. The boom in theorizing means that specializations have allowed political scientists to fine-tune their in-depth analysis in order to capture smaller and more specific movements of democratic progress and regress. But the multiplicity of models of the crisis and transformation of democracy also spells some bad news, which is far less often acknowledged and far less understood. This article seeks to shed light on the dangers of not comparing and integrating various models of democracy and to extrapolate the benefits of using the comparative method to do so.

AbstractIn the context of a long‐standing academic acceptance of the socially structured nature of health inequalities, there has been a growing literature that critically examines policies that aim to reduce them. This has demonstrated inadequate policy assessment of the nature of the problem of health inequalities and correspondingly partial solutions that privilege interventions that focus on individual lifestyle solutions over more structural approaches. Much of the research that has been undertaken in this field to explore competing theories of inequalities has analyzed national policy documents or the views of senior policy advisers rather than practitioners.This study uses Raphael's 'seven discourses of the social determinants of health' to understand the implicit theories of health inequalities of both practitioners and policymakers working within a single health care system as they talk about different policy typologies. To help penetrate potentially well‐rehearsed discourses about health inequalities, it tests a visual method of stimulating discussion about how different types of policy might operate to narrow/widen existing gaps in outcomes. Building on Raphael, it finds that individuals' theories of health inequalities contain co‐existing although not synthesized material and behavioural explanations and that, although the social patterning of material disadvantage was recognized, the role of power and politics is underplayed. Variations between participants did not align with role (policy/practice) and using visual methods to represent the impact of different policy types on health inequalities, though challenging for participants, stimulated reflection about a subject matter that has otherwise become rather stagnant.

For some, market failures serve as a rationale for public intervention. However, the fact that self-interested market behavior does not always produce felicitous social consequences is not sufficient reason to draw this conclusion. It is necessary to assess public performance under comparable conditions, and hence to analyze self-interested political behavior in the institutional structures of the public sector. Our approach emphasizes this institutional structure—warts and all—and thereby provides specific cautionary warnings about optimistic reliance on political institutions to improve upon market performance.

Business Statistics with Solutions in R covers a wide range of applications of statistics in solving business related problems. It will introduce readers to quantitative tools that are necessary for daily business needs and help them to make evidence-based decisions. The book provides an insight on how to summarize data, analyze it, and draw meaningful inferences that can be used to improve decisions. It will enable readers to develop computational skills and problem-solving competence using the open source language, R. Mustapha Abiodun Akinkunmi uses real life business data for illustrative examples while discussing the basic statistical measures, probability, regression analysis, significance testing, correlation, the Poisson distribution, process control for manufacturing, time series analysis, forecasting techniques, exponential smoothing, univariate and multivariate analysis including ANOVA and MANOVA and more in this valuable reference for policy makers, professionals, academics and individuals interested in the areas of business statistics, applied statistics, statistical computing, finance, management and econometrics

The banking crisis revealed severe shortcomings in the area of monetary policy, deregulation, financial innovation, and government policies. Given the negative impact it has had on the global economy, it requires an analysis of the factors that contributed to its onset, its particularities and the solutions implemented. The aim of the paper is to draw a clear picture of the phenomenon and to identify possible solutions. By analyzing the causes and evolution of the recent banking crisis, the authors suggest strategies aimed at avoiding similar future banking crises.