New approaches to characterizing and understanding biofouling of spiral wound membrane systems

2012 ◽  
Vol 66 (1) ◽  
pp. 88-94 ◽  
Author(s):  
Mark C. M. van Loosdrecht ◽  
Ludmilla Bereschenko ◽  
Andrea Radu ◽  
Joop C. Kruithof ◽  
Cristian Picioreanu ◽  
...  

Historically, biofouling research on spiral wound membrane systems is typically problem solving oriented. Membrane modules are studied as black box systems, investigated by autopsies. Biofouling is not a simple process. Many factors influence each other in a non-linear fashion. These features make biofouling a subject which is not easy to study using a fundamental scientific approach. Nevertheless to solve or minimize the negative impacts of biofouling, a clear understanding of the interacting basic principles is needed. Recent research into microbiological characterizing of biofouling, small scale test units, application of in situ visualization methods, and model approaches allow such an integrated study of biofouling.

1995 ◽  
Vol 415 ◽  
Author(s):  
Brian J. Rappoli ◽  
William J. DeSisto

ABSTRACTUV spectroscopy has been used as an in situ diagnostic to measure the gas phase concentration of 2,2,6,6-tetramethyl-3,5-heptanedionate (thd) complexes of Ba, Cu and Y in metalorganic chemical vapor deposition (MOCVD) bubbler effluent. These precursors for MOCVD synthesis of YBa2Cu37−δ (YBCO) show marked instability in gas phase concentration as a function of time during bubbler purge. The UV diagnostic technique has been applied to both a small scale test system and a commercial scale MOCVD reactor.


2019 ◽  
Vol 1 (1) ◽  
pp. 79-87
Author(s):  
Sugian Nurwijaya

This is a research and developmentstudy with limited trials which aims to develop the Mathematics Learning Package by using a geogebra-assisted scientific approach in the eight grade of MTs Al-Junaidiyah Biru, Bone Regency. Such learning package includes student books, student activity sheets, learning implementation plans and learning outcomes test. The subjects of this study were twenty two students of class VIIIC MTs Al-Junaidiyah Biru Bone Regency. The development procedure used in this study is the Thiagarajan model or 4D model (Define, Design, Develop, and Disseminate) which includes four phases, namely the limitation, the design, the development, and the small scale distribution phase. Learning packagewith geogebra-assisted scientific approach that had been developed have been validated by experts and have been revised so that results are feasible to use. The results of limited trials show that the learning package produced has been practical and effective. (4) skor rata-rata yang diperoleh siswa pada tes hasil belajar adalah 78,40 dari skor ideal 100 dengan standar deviasi 11,89. Dimana 19 dari 22 siswa atau 86,36% memenuhi ketuntasan individu yang menunjukkan bahwa ketuntasan klasikal tercapai.The results of data analysis are as follows: (1) teacher activities can guide groups to work and learneffectively; (2) students generally give the positive responses to the developed learning package; (3) mathematics learning package with geogebra-assisted scientific approach make students more active in the learning process; (4) the average score obtained by students on the learning outcomes test is 78.40 from the ideal score of 100 with a standard deviation of 11.89. Then, 19 of 22 students or 86.36% fulfilled individual completeness which shows that classical completeness was achieved


2010 ◽  
Author(s):  
Jon La Follett ◽  
John Stroud ◽  
Pat Malvoso ◽  
Joseph Lopes ◽  
Raymond Lim ◽  
...  

Author(s):  
D.M. Seyedi ◽  
C. Plúa ◽  
M. Vitel ◽  
G. Armand ◽  
J. Rutqvist ◽  
...  

2021 ◽  
Vol 13 (9) ◽  
pp. 5033
Author(s):  
Linda Novosadová ◽  
Wim van der Knaap

The present research offers an exploration into the biophilic approach and the role of its agents in urban planning in questions of building a green, resilient urban environment. Biophilia, the innate need of humans to connect with nature, coined by Edgar O. Wilson in 1984, is a concept that has been used in urban governance through institutions, agents’ behaviours, activities and systems to make the environment nature-inclusive. Therefore, it leads to green, resilient environments and to making cities more sustainable. Due to an increasing population, space within and around cities keeps on being urbanised, replacing natural land cover with concrete surfaces. These changes to land use influence and stress the environment, its components, and consequently impact the overall resilience of the space. To understand the interactions and address the adverse impacts these changes might have, it is necessary to identify and define the environment’s components: the institutions, systems, and agents. This paper exemplifies the biophilic approach through a case study in the city of Birmingham, United Kingdom and its biophilic agents. Using the categorisation of agents, the data obtained through in-situ interviews with local professionals provided details on the agent fabric and their dynamics with the other two environments’ components within the climate resilience framework. The qualitative analysis demonstrates the ways biophilic agents act upon and interact within the environment in the realm of urban planning and influence building a climate-resilient city. Their activities range from small-scale community projects for improving their neighbourhood to public administration programs focusing on regenerating and regreening the city. From individuals advocating for and educating on biophilic approach, to private organisations challenging the business-as-usual regulations, it appeared that in Birmingham the biophilic approach has found its representatives in every agent category. Overall, the activities they perform in the environment define their role in building resilience. Nonetheless, the role of biophilic agents appears to be one of the major challengers to the urban design’s status quo and the business-as-usual of urban governance. Researching the environment, focused on agents and their behaviour and activities based on nature as inspiration in addressing climate change on a city level, is an opposite approach to searching and addressing the negative impacts of human activity on the environment. This focus can provide visibility of the local human activities that enhance resilience, while these are becoming a valuable input to city governance and planning, with the potential of scaling it up to other cities and on to regional, national, and global levels.


Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 646 ◽  
Author(s):  
García-Díaz ◽  
Patiño ◽  
Vázquez ◽  
Gil-Serna

Aflatoxin (AF) contamination of maize is a major concern for food safety. The use of chemical fungicides is controversial, and it is necessary to develop new effective methods to control Aspergillus flavus growth and, therefore, to avoid the presence of AFs in grains. In this work, we tested in vitro the effect of six essential oils (EOs) extracted from aromatic plants. We selected those from Satureja montana and Origanum virens because they show high levels of antifungal and antitoxigenic activity at low concentrations against A. flavus. EOs are highly volatile compounds and we have developed a new niosome-based encapsulation method to extend their shelf life and activity. These new formulations have been successfully applied to reduce fungal growth and AF accumulation in maize grains in a small-scale test, as well as placing the maize into polypropylene woven bags to simulate common storage conditions. In this latter case, the antifungal properties lasted up to 75 days after the first application.


2010 ◽  
Author(s):  
O. Ciricosta ◽  
L. Labate ◽  
S. Atzeni ◽  
A. Barbini ◽  
D. Batani ◽  
...  
Keyword(s):  

2000 ◽  
Vol 663 ◽  
Author(s):  
J. Samper ◽  
R. Juncosa ◽  
V. Navarro ◽  
J. Delgado ◽  
L. Montenegro ◽  
...  

ABSTRACTFEBEX (Full-scale Engineered Barrier EXperiment) is a demonstration and research project dealing with the bentonite engineered barrier designed for sealing and containment of waste in a high level radioactive waste repository (HLWR). It includes two main experiments: an situ full-scale test performed at Grimsel (GTS) and a mock-up test operating since February 1997 at CIEMAT facilities in Madrid (Spain) [1,2,3]. One of the objectives of FEBEX is the development and testing of conceptual and numerical models for the thermal, hydrodynamic, and geochemical (THG) processes expected to take place in engineered clay barriers. A significant improvement in coupled THG modeling of the clay barrier has been achieved both in terms of a better understanding of THG processes and more sophisticated THG computer codes. The ability of these models to reproduce the observed THG patterns in a wide range of THG conditions enhances the confidence in their prediction capabilities. Numerical THG models of heating and hydration experiments performed on small-scale lab cells provide excellent results for temperatures, water inflow and final water content in the cells [3]. Calculated concentrations at the end of the experiments reproduce most of the patterns of measured data. In general, the fit of concentrations of dissolved species is better than that of exchanged cations. These models were later used to simulate the evolution of the large-scale experiments (in situ and mock-up). Some thermo-hydrodynamic hypotheses and bentonite parameters were slightly revised during TH calibration of the mock-up test. The results of the reference model reproduce simultaneously the observed water inflows and bentonite temperatures and relative humidities. Although the model is highly sensitive to one-at-a-time variations in model parameters, the possibility of parameter combinations leading to similar fits cannot be precluded. The TH model of the “in situ” test is based on the same bentonite TH parameters and assumptions as for the “mock-up” test. Granite parameters were slightly modified during the calibration process in order to reproduce the observed thermal and hydrodynamic evolution. The reference model captures properly relative humidities and temperatures in the bentonite [3]. It also reproduces the observed spatial distribution of water pressures and temperatures in the granite. Once calibrated the TH aspects of the model, predictions of the THG evolution of both tests were performed. Data from the dismantling of the in situ test, which is planned for the summer of 2001, will provide a unique opportunity to test and validate current THG models of the EBS.


Author(s):  
Richard Clements ◽  
Andrew D. Ethridge

This paper describes further investigations, utilising small scale test cells, into the general corrosion which can occur on wires within the inherent annulus space in a flexible pipe, particularly, and for the first time, in a sour service (H2S containing) environment. The work enhances data presented previously in 2002. Tests have been performed in cells specifically designed to simulate, as closely as possible, the environment and confines of a flexible pipe annulus, using solutions of both deionized water and seawater (to represent seawater flooding and condensed water). The systems were saturated with CO2 and H2S to simulate permeation of gases through the polymer pressure sheath (as predicted by validated permeation models). Weight loss measurements were undertaken in order to quantify the corrosion rate in these simulated annulus environments and metallography was undertaken to characterise the corrosion and check for HIC/SOHIC.


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