2,873 research outputs found

    International relations’ first great debate: context and tradition

    No full text
    According to International Relations (IR) orthodoxy, the story of three Great Debates accounts for the most important theoretical developments in the discipline. Over the last decade, critical historiographers have established that the story of a First Debate, which tells of a struggle between idealism and realism between the 1920s and 1940s, is a misleading caricature of early academic international thought. This article adds to this critical literature by tracing the manner in which the story of a First Debate became a part of disciplinary orthodoxy between the 1950s and 1980s. Our analysis reveals that a myth of a First Debate was produced when more recent scholars detached the concept of a struggle between idealism and realism from both the unique historical milieu in which this dichotomy was conceived, and the rhetorical purposes for which it was employed. We use these findings to make the case for a contextual approach to disciplinary historiography, and to illuminate the historical contingency of contemporary notions of scholarly purpose in IR

    Submerged membrane coagulation hybrid system as pretreatment to organic matter removal from seawater

    Full text link
    In this study, a commonly used ferric chloride was utilised as coagulant for removing organic compounds from seawater. More than 57% of dissolved organic carbon (DOC) was removed at optimum dosage of 3 mg Fe+3/L. The coagulation by FeCl3 at optimum dosage could remove a majority (95%) of hydrophobic compounds. The results from Liquid Chromatography - Organic Carbon Detector showed that only <0.02 mg/L of hydrophobic compounds was found after coagulation. In addition, the modified fouling index decreased considerably from 15,848 s/L2 with raw seawater to 3,025 s/L 2 with seawater after coagulation. In-line coagulation coupled with submerged membrane system (ICSMS) was also trialled. It is observed that critical flux was increased from 20 L/m2·h in the conventional submerged membrane system to 55 L/m2 h in ICSMS. The ICSMS could remain the high DOC removal efficiency (more than 70%) at filtration rate of 20 L/m2 h when keeping the development of trans-membrane pressure was significant lower than that of conventional submerged membrane system. © IWA Publishing 2011

    Effluent organic matter (EfOM) in wastewater: Constituents, effects, and treatment

    Full text link
    Wastewater reuse is being increasingly emphasized as a strategy for conservation of limited resources of freshwater and as a mean of safeguarding the aquatic environment due to contaminants present in wastewater. Although secondary and tertiary treated wastewater is often discharged into surface waters, it cannot be reused without further treatment. One of the parameters of concern for human and environmental health is components of organic matter originating from wastewater treatment plant (WWTP) effluents. This effluent organic matter (EfOM) should be carefully characterized in order to find an optimum treatment method for water reuse. This review presents the components of EfOM present in WWTP effluents and various treatment methods that may be employed for reduction of EfOM. These processes include flocculation, adsorption, biofiltration, ion exchange, advanced oxidation process, and membrane technology. The removal efficiency is discussed in terms of removal of total organic carbon, endocrine-disrupting chemicals (EDCs), pharmaceuticals and personal care products (PPCPs), different polarity fractions (such as hydrophobic and hydrophilic), and molecular weight distribution of organic matter. Copyright © Taylor & Francis Group, LLC

    Effect of flocculation and/or adsorption as pretreatment on the critical flux of crossflow microfiltration

    Full text link
    This study aims at identifying the effect of pretreatment such as flocculation and/or adsorption on the performance of crossflow microfiltration (CFMF). CFMF performance was studied in terms of critical flux. The results indicated that: (1) flocculation alone as a pretreatment could effectively remove the large molecular weight organic matter from 30,000 to 60,000 Daltons; (2) flocculation, together with adsorption as a pretreatment to CFMF, could remove both large and small molecular weight organics; (3) flocculation as a pretreatment was significantly better than adsorption in improving the critical flux; (4) critical flux increased from 100 L/m2.h to 520 L/m2.h when flocculation-adsorption was applied. The critical flux in long-term experiments was the same as that of the short-term experiments. However, the critical flux slightly decreased (5%) in long-term experiments compared to short-term operation with flocculation and adsorption as a pretreatment. © 2005 Elsevier B.V. All rights reserved

    Effect of Photocatalysis on the Membrane Hybrid System for wastewater treatment

    Full text link
    An integrated photocatalysismembrane hybrid system was investigated for wastewater treatment with the main focus on improving the cross flow microfiltration (MF) permeate flux. Photocatalysis with TiO2 (P25 Degussa) suspension as photocatalyst was applied both as pre-treatment and as inline treatment with MF. The TiO2 slurry was found to have significant effect in permeate flux for wastewater with lower dissolved organic carbon concentration. The MF flux decline due to TiO2 slurry cake on the membrane surface was minimized by allowing the TiO2 slurry to settle and by using only the supernatant for further treatment using the hybrid system. The investigation also included the study on the effect of photocatalytic reaction time and the slurry settling times on the MF permeate flux. The irradiation of ultraviolet on the MF surface in presence of TiO2 catalyst in suspension yielded in an increase in permeate flux

    Effect of periodic backwash in the submerged membrane adsorption hybrid system

    Get PDF
    The submerged membrane adsorption hybrid system (SMAHS) is an attractive solution in treating wastewater; however it faces membrane fouling although to a less extent. In this study, different adsorbents and resins were investigated in order to find a substitute to the powdered activated carbon (PAC); The effect of new backflush was also studied in further reducing the membrane fouling. The SMAHS led to 72–86% dissolved organic carbon (DOC) removal. A detailed study on the transmembrane pressure development led to a conclusion that there is a critical flux and this value is around 16 l/h.m2 for the wastewater studied

    Enhanced Adaptive Array Performance Via DOA Detection

    Get PDF
    In various communications-based adaptive array applications, the directions of arrival (DOAs) of the desired user signal are sparsely separated. As such, the desired beam-pattern has a sparse structure. We propose an NLMS-based adaptive algorithm which exploits this sparse DOA structure and provides significantly improved convergence speeds

    Lessons for a viable water recycling industry

    Full text link
    The platform on which the Labour government came to power in Australia in November 2007 included a policy of setting a national wastewater recycling target of 30% by the year 2015. A similar target-based approach was followed by the solid waste recycling industry in Australia the policy of which focused on supply and did not adequately acknowledge the price competitiveness of the product and its demand. This paper highlights the lessons from the solid waste recycling industry and applies them to the water recycling sector. A sound water pricing regime that reflects the true costs of water and a competitive water industry is offered as a better policy alternative to setting recycling targets
    corecore