Science.gov

Sample records for aerated concrete aac

  1. Methane biofiltration using autoclaved aerated concrete as the carrier material.

    PubMed

    Ganendra, Giovanni; Mercado-Garcia, Daniel; Hernandez-Sanabria, Emma; Boeckx, Pascal; Ho, Adrian; Boon, Nico

    2015-09-01

    The methane removal capacity of mixed methane-oxidizing bacteria (MOB) culture in a biofilter setup using autoclaved aerated concrete (AAC) as a highly porous carrier material was tested. Batch experiment was performed to optimize MOB immobilization on AAC specimens where optimum methane removal was obtained when calcium chloride was not added during bacterial inoculation step and 10-mm-thick AAC specimens were used. The immobilized MOB could remove methane at low concentration (~1000 ppmv) in a biofilter setup for 127 days at average removal efficiency (RE) of 28.7 %. Unlike a plug flow reactor, increasing the total volume of the filter by adding a biofilter in series did not result in higher total RE. MOB also exhibited a higher abundance at the bottom of the filter, in proximity with the methane gas inlet where a high methane concentration was found. Overall, an efficient methane biofilter performance could be obtained using AAC as the carrier material.

  2. Methane biofiltration using autoclaved aerated concrete as the carrier material.

    PubMed

    Ganendra, Giovanni; Mercado-Garcia, Daniel; Hernandez-Sanabria, Emma; Boeckx, Pascal; Ho, Adrian; Boon, Nico

    2015-09-01

    The methane removal capacity of mixed methane-oxidizing bacteria (MOB) culture in a biofilter setup using autoclaved aerated concrete (AAC) as a highly porous carrier material was tested. Batch experiment was performed to optimize MOB immobilization on AAC specimens where optimum methane removal was obtained when calcium chloride was not added during bacterial inoculation step and 10-mm-thick AAC specimens were used. The immobilized MOB could remove methane at low concentration (~1000 ppmv) in a biofilter setup for 127 days at average removal efficiency (RE) of 28.7 %. Unlike a plug flow reactor, increasing the total volume of the filter by adding a biofilter in series did not result in higher total RE. MOB also exhibited a higher abundance at the bottom of the filter, in proximity with the methane gas inlet where a high methane concentration was found. Overall, an efficient methane biofilter performance could be obtained using AAC as the carrier material. PMID:25967655

  3. Cracking in autoclaved aerated concrete: Experimental investigation and XFEM modeling

    SciTech Connect

    Ferretti, D.

    2015-01-15

    The paper aims to investigate and model cracking development in beams and deep-beams made of autoclaved aerated concrete (AAC). Fracture mechanics of AAC has been first studied by performing three-point bending tests on beams, similar to those commonly used for ordinary concrete elements. In some of these tests, crack growth has been also monitored by using ESPI laser technique. In this way, it has been possible to calibrate the main parameters of a proper cohesive law by means of extended finite element inverse analysis. Subsequently, cracking tests have been also performed on deep-beams, whose behavior is more representative of full scale walls. To validate the proposed cohesive law, deep-beam experimental behavior has been finally simulated through XFEM.

  4. Non-autoclaved aerated concrete with mineral additives

    NASA Astrophysics Data System (ADS)

    Il'ina, L. V.; Rakov, M. A.

    2016-01-01

    We investigated the effect of joint grinding of Portland cement clinker, silica and carbonate components and mineral additives to specific surface of 280 - 300 m2/kg on the properties (strength, average density and thermal conductivity) of non-autoclaved aerated concrete, and the porosity of the hardened cement paste produced from Portland cement clinker with mineral additives. The joint grinding of the Portland cement clinker with silica and carbonate components and mineral additives reduces the energy consumption of non-autoclaved aerated concrete production. The efficiency of mineral additives (diopside, wollastonite) is due to the closeness the composition, the type of chemical bonds, physical and chemical characteristics (specific enthalpy of formation, specific entropy) to anhydrous clinker minerals and their hydration products. Considering the influence of these additions on hydration of clinker minerals and formation of hardened cement paste structure, dispersed wollastonite and diopside should be used as mineral additives. The hardness and, consequently, the elastic modulus of diopside are higher than that of hardened cement paste. As a result, there is a redistribution of stresses in the hardened cement paste interporous partitions and hardening, both the partitions and aerated concrete on the whole. The mineral additives introduction allowed to obtain the non-autoclaved aerated concrete with average density 580 kg/m3, compressive strength of 3.3 MPa and thermal conductivity of 0.131 W/(m.°C).

  5. Binary Effect of Fly Ash and Palm Oil Fuel Ash on Heat of Hydration Aerated Concrete

    PubMed Central

    Mehmannavaz, Taha; Ismail, Mohammad; Radin Sumadi, Salihuddin; Rafique Bhutta, Muhammad Aamer; Samadi, Mostafa

    2014-01-01

    The binary effect of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) on heat of hydration of aerated concrete was studied. Three aerated concrete mixes were prepared, namely, concrete containing 100% ordinary Portland cement (control sample or Type I), binary concrete made from 50% POFA (Type II), and ternary concrete containing 30% POFA and 20% PFA (Type III). It is found that the temperature increases due to heat of hydration through all the concrete specimens especially in the control sample. However, the total temperature rises caused by the heat of hydration through both of the new binary and ternary concrete were significantly lower than the control sample. The obtained results reveal that the replacement of Portland cement with binary and ternary materials is beneficial, particularly for mass concrete where thermal cracking due to extreme heat rise is of great concern. PMID:24696646

  6. Binary effect of fly ash and palm oil fuel ash on heat of hydration aerated concrete.

    PubMed

    Mehmannavaz, Taha; Ismail, Mohammad; Radin Sumadi, Salihuddin; Rafique Bhutta, Muhammad Aamer; Samadi, Mostafa; Sajjadi, Seyed Mahdi

    2014-01-01

    The binary effect of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) on heat of hydration of aerated concrete was studied. Three aerated concrete mixes were prepared, namely, concrete containing 100% ordinary Portland cement (control sample or Type I), binary concrete made from 50% POFA (Type II), and ternary concrete containing 30% POFA and 20% PFA (Type III). It is found that the temperature increases due to heat of hydration through all the concrete specimens especially in the control sample. However, the total temperature rises caused by the heat of hydration through both of the new binary and ternary concrete were significantly lower than the control sample. The obtained results reveal that the replacement of Portland cement with binary and ternary materials is beneficial, particularly for mass concrete where thermal cracking due to extreme heat rise is of great concern.

  7. Binary effect of fly ash and palm oil fuel ash on heat of hydration aerated concrete.

    PubMed

    Mehmannavaz, Taha; Ismail, Mohammad; Radin Sumadi, Salihuddin; Rafique Bhutta, Muhammad Aamer; Samadi, Mostafa; Sajjadi, Seyed Mahdi

    2014-01-01

    The binary effect of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) on heat of hydration of aerated concrete was studied. Three aerated concrete mixes were prepared, namely, concrete containing 100% ordinary Portland cement (control sample or Type I), binary concrete made from 50% POFA (Type II), and ternary concrete containing 30% POFA and 20% PFA (Type III). It is found that the temperature increases due to heat of hydration through all the concrete specimens especially in the control sample. However, the total temperature rises caused by the heat of hydration through both of the new binary and ternary concrete were significantly lower than the control sample. The obtained results reveal that the replacement of Portland cement with binary and ternary materials is beneficial, particularly for mass concrete where thermal cracking due to extreme heat rise is of great concern. PMID:24696646

  8. Structure formation of aerated concrete containing waste coal combustion products generated in the thermal vortex power units

    NASA Astrophysics Data System (ADS)

    Ivanov, A. I.; Stolboushkin, A. Yu; Temlyanstev, M. V.; Syromyasov, V. A.; Fomina, O. A.

    2016-10-01

    The results of fly ash research, generated in the process of waste coal combustion in the thermal vortex power units and used as an aggregate in aerated concrete, are provided. It is established that fly ash can be used in the production of cement or concrete with low loss on ignition (LOI). The permitted value of LOI in fly ash, affecting the structure formation and operational properties of aerated concrete, are defined. During non-autoclaved hardening of aerated concrete with fly ash aggregate and LOI not higher than 2%, the formation of acicular crystals of ettringite, reinforcing interporous partitions, takes place.

  9. Strain rate sensitivity of autoclaved aerated concrete from quasi-static regime to shock loading

    NASA Astrophysics Data System (ADS)

    Mespoulet, Jérôme; Plassard, Fabien; Hereil, Pierre Louis

    2015-09-01

    The quasi-static mechanical behavior of autoclaved aerated concrete is well-known and can be expressed as a function of its density. There are however not much studies dealing with its dynamic behavior and its damping ability when subjected to a mechanical shock or a blast. This study presents experimental results obtained at the Shock Physics Laboratory of THIOT INGENIERIE company. The test specimens are made of YTONG(TM ) cellular concrete with porosity in the range of 75 to 80%. Experimental tests cover a large strain rate amplitude (higher than 104 s-1) for specimens up to 250 mm. They were carried out with a small compression press and with two facilities dedicated to dynamic material characterization: JUPITER dynamic large press (2 MN, 3 ms rising time) and TITAN multi-caliber single-stage gas gun. Results in un-confined conditions show an increase of the compressive strength when strain rate increases (45% increase at 5.102 s-1) but dynamic tests induce damage early in the experiment. This competition between dynamic strength raise and specimen fracture makes the complete compaction curve determination not to be done in unconfined dynamic condition. A 25% increase of the compressive strength has been observed between unconfined and confined condition in Q.S. regime.

  10. Gaseous mercury release during steam curing of aerated concretes that contain fly ash and activated carbon sorbent

    SciTech Connect

    Danold W. Golightly; Chin-Min Cheng; Ping Sun; Linda K. Weavers; Harold W. Walker; Panuwat Taerakul; William E. Wolfe

    2008-09-15

    Gaseous mercury released from aerated concrete during both presteam curing at 25{sup o}C and steam curing at 80{sup o}C was measured in controlled laboratory experiments. Mercury release originated from two major components in the concrete mixture: (1) class F coal fly ash and (2) a mixture of the fly ash and powdered activated carbon onto which elemental mercury was adsorbed. Mercury emitted during each curing cycle was collected on iodated carbon traps in a purge-and-trap arrangement and subsequently measured by cold-vapor atomic fluorescence spectrometry. Through 3 h of presteam curing, the release of mercury from the freshly prepared mixture was less than 0.03 ng/kg of concrete. Releases of total mercury over the 21 h steam curing process ranged from 0.4 to 5.8 ng of mercury/kg of concrete and depended upon mercury concentrations in the concrete. The steam-cured concrete had a higher mercury release rate (ng kg{sup -1} h{sup -1}) compared to air-cured concrete containing fly ash, but the shorter curing interval resulted in less total release of mercury from the steam-cured concrete. The mercury flux from exposed concrete surfaces to mercury-free air ranged from 0.77 to 11.1 ng m{sup -2} h{sup -1}, which was similar to mercury fluxes for natural soils to ambient air of 4.2 ng m{sup -2} h{sup -1} reported by others. Less than 0.022% of the total quantity of mercury present from all mercury sources in the concrete was released during the curing process, and therefore, nearly all of the mercury was retained in the concrete. 31 refs., 4 figs., 2 tabs.

  11. Energy performance evaluation of AAC

    NASA Astrophysics Data System (ADS)

    Aybek, Hulya

    was accomplished by using conducting several simulation models to determine the relative energy efficiency of wood-framed, metal-framed, and Aerated Autoclaved Concrete (AAC) wall structures for both commercial and residential buildings.

  12. In situ time-resolved X-ray diffraction of tobermorite formation in autoclaved aerated concrete: Influence of silica source reactivity and Al addition

    SciTech Connect

    Matsui, Kunio; Kikuma, Jun; Tsunashima, Masamichi; Ishikawa, Tetsuji; Matsuno, Shin-ya; Ogawa, Akihiro; Sato, Masugu

    2011-05-15

    The hydrothermal formation of tobermorite during the processing of autoclaved aerated concrete was investigated by in situ X-ray diffraction (XRD) analysis. High-energy X-rays from a synchrotron radiation source in combination with a newly developed autoclave cell and a photon-counting pixel array detector were used. To investigate the effects of the silica source, reactive quartz from chert and less-reactive quartz from quartz sand were used as starting materials. The effect of Al addition on tobermorite formation was also studied. In all cases, C-S-H, hydroxylellestadite and katoite were clearly observed as intermediates. Acceleration of tobermorite formation by Al addition was clearly observed. However, Al addition did not affect the dissolution rate of quartz. Two pathways, via C-S-H and katoite, were also observed in the Al-containing system. These results suggest that the structure of initially formed C-S-H is important for the subsequent tobermorite formation reactions.

  13. Photocatalytic activity of titanium dioxide nanoparticle coatings applied on autoclaved aerated concrete: effect of weathering on coating physical characteristics and gaseous toluene removal.

    PubMed

    Maury-Ramirez, Anibal; Demeestere, Kristof; De Belie, Nele

    2012-04-15

    Autoclaved aerated concrete has been coated by TiO(2) nanoparticles through a dip-coating (DC) and a novel vacuum saturation (VS) method to investigate the weathering resistance and gaseous toluene removal potential of both coating types. The effect of intensive weathering - corresponding to a period of about 25 years - on the coating characteristics was studied in terms of TiO(2) content, coating thickness and color changes. Toluene removal was investigated in a lab-scale flow-through photoreactor at 24°C and 52% relative humidity, and results obtained immediately after application of the coatings and after two weathering stages were compared. Weathering of the DC and VS coated samples resulted into a decrease of the coating layer thickness of more than 98%, confirmed by a decline in TiO(2) content by more than 99% and 93%, respectively. Surprisingly, toluene removal efficiencies before and after weathering kept constant at about 95% for both coating types, corresponding to an elimination rate of 60-70 mg/(m(2)h) at an initial toluene concentration of 15 ppm(v) and a gas residence time of 3 min. Increasing the toluene load by applying higher toluene inlet concentrations (up to 35 ppm(v)) and lower gas residence times (1 min) did decrease the toluene removal efficiency to 32-41%, but elimination rates increased up to 214 mg/(m(2)h), being a factor of 1.6-4.5 times higher than reported in recent work.

  14. AAC Modeling Intervention Research Review

    ERIC Educational Resources Information Center

    Sennott, Samuel C.; Light, Janice C.; McNaughton, David

    2016-01-01

    A systematic review of research on the effects of interventions that include communication partner modeling of aided augmentative and alternative communication (AAC) on the language acquisition of individuals with complex communication needs was conducted. Included studies incorporated AAC modeling as a primary component of the intervention,…

  15. Personnel roles in the AAC assessment process.

    PubMed

    Binger, Cathy; Ball, Laura; Dietz, Aimee; Kent-Walsh, Jennifer; Lasker, Joanne; Lund, Shelley; McKelvey, Miechelle; Quach, Wendy

    2012-12-01

    Completing an augmentative and alternative communication (AAC) assessment is a complex process that involves many stakeholders and professionals. To help clarify professional roles and provide assessment guidelines, an AAC Assessment Personnel Framework was developed. This framework was adapted from the work of Beukelman, Ball, and Fager in 2008, which focused on general AAC needs (not just assessment) and concentrated specifically on adults. In contrast, the present model examines the assessment process for all individuals who require AAC. The following AAC assessment personnel are discussed: AAC finders, general practice SLPs, AAC clinical specialists, facilitators and communication partners, collaborating professionals, AAC research and policy specialists, manufacturers and vendors, funding agencies and personnel, and AAC/assistive technology agencies and personnel. Current barriers for successful assessment outcomes are discussed, and suggestions for addressing personnel-related barriers are explored. PMID:23256859

  16. USING AERATION FOR CORROSION CONTROL

    EPA Science Inventory

    Aeration is a useful drinking water treatment process. Aeration has been used to remove hydrogen sulfide, methane, radon, iron, manganese, and volatile organic contaminants (VOCs) from drinking water. Aeration is also effective in removing carbon dioxide which directly impacts ...

  17. 75 FR 22165 - Request for Certification of Compliance-Rural Industrialization Loan and Grant Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-27

    ... produce autoclaved aerated concrete (AAC) ``green'' building materials. The NAICS industry code for this enterprise is: 327331 Concrete Block and Brick Manufacturing. DATES: All interested parties may...

  18. Responses to the AAC and U Statement

    ERIC Educational Resources Information Center

    Hollinger, David A.; Neal, Anne D.; Robbins, Bruce

    2006-01-01

    Academic freedom is an institutionally specific type of liberty. It gains its character from the rules of evidence and reasoning used by communities of scientists and scholars to determine the relative value of truth-claims. One of the finest virtues of the Association of American Colleges and Universities (AAC&U) Statement on Academic Freedom and…

  19. Biogenic concrete protection driven by the formate oxidation by Methylocystis parvus OBBP.

    PubMed

    Ganendra, Giovanni; Wang, Jianyun; Ramos, Jose A; Derluyn, Hannelore; Rahier, Hubert; Cnudde, Veerle; Ho, Adrian; Boon, Nico

    2015-01-01

    The effectiveness of Microbiologically Induced Carbonate Precipitation (MICP) from the formate oxidation by Methylocystis parvus OBBP as an alternative process for concrete protection was investigated. MICP was induced on Autoclaved Aerated Concrete (AAC), the model material, by immersing the material in 10(9) M. parvus cells mL(-1) containing 5 g L(-1) of calcium formate. A 2 days immersion of the material gave the maximum weight increase of the specimens (38 ± 19 mg) and this was likely due to the deposition of calcium carbonate, biomass, and unconverted calcium formate. The solid deposition mainly occurred in the micropores of the specimen, close to the outer surface. A significantly lower water absorption was observed in the bacterially treated specimens compared to the non-treated ones (up to 2.92 ± 0.91 kg m(-2)) and this could be attributed to the solid deposition. However, the sonication test demonstrated that the bacterial treatment did not give a consolidating effect to the material. Overall, compared to the currently employed urea hydrolysis process, the formate-based MICP by M. parvus offers a more environmentally friendly approach for the biotechnological application to protect concrete. PMID:26284061

  20. Biogenic concrete protection driven by the formate oxidation by Methylocystis parvus OBBP.

    PubMed

    Ganendra, Giovanni; Wang, Jianyun; Ramos, Jose A; Derluyn, Hannelore; Rahier, Hubert; Cnudde, Veerle; Ho, Adrian; Boon, Nico

    2015-01-01

    The effectiveness of Microbiologically Induced Carbonate Precipitation (MICP) from the formate oxidation by Methylocystis parvus OBBP as an alternative process for concrete protection was investigated. MICP was induced on Autoclaved Aerated Concrete (AAC), the model material, by immersing the material in 10(9) M. parvus cells mL(-1) containing 5 g L(-1) of calcium formate. A 2 days immersion of the material gave the maximum weight increase of the specimens (38 ± 19 mg) and this was likely due to the deposition of calcium carbonate, biomass, and unconverted calcium formate. The solid deposition mainly occurred in the micropores of the specimen, close to the outer surface. A significantly lower water absorption was observed in the bacterially treated specimens compared to the non-treated ones (up to 2.92 ± 0.91 kg m(-2)) and this could be attributed to the solid deposition. However, the sonication test demonstrated that the bacterial treatment did not give a consolidating effect to the material. Overall, compared to the currently employed urea hydrolysis process, the formate-based MICP by M. parvus offers a more environmentally friendly approach for the biotechnological application to protect concrete.

  1. Biogenic concrete protection driven by the formate oxidation by Methylocystis parvus OBBP

    PubMed Central

    Ganendra, Giovanni; Wang, Jianyun; Ramos, Jose A.; Derluyn, Hannelore; Rahier, Hubert; Cnudde, Veerle; Ho, Adrian; Boon, Nico

    2015-01-01

    The effectiveness of Microbiologically Induced Carbonate Precipitation (MICP) from the formate oxidation by Methylocystis parvus OBBP as an alternative process for concrete protection was investigated. MICP was induced on Autoclaved Aerated Concrete (AAC), the model material, by immersing the material in 109 M. parvus cells mL−1 containing 5 g L−1 of calcium formate. A 2 days immersion of the material gave the maximum weight increase of the specimens (38 ± 19 mg) and this was likely due to the deposition of calcium carbonate, biomass, and unconverted calcium formate. The solid deposition mainly occurred in the micropores of the specimen, close to the outer surface. A significantly lower water absorption was observed in the bacterially treated specimens compared to the non-treated ones (up to 2.92 ± 0.91 kg m−2) and this could be attributed to the solid deposition. However, the sonication test demonstrated that the bacterial treatment did not give a consolidating effect to the material. Overall, compared to the currently employed urea hydrolysis process, the formate-based MICP by M. parvus offers a more environmentally friendly approach for the biotechnological application to protect concrete. PMID:26284061

  2. Catfish production using intensive aeration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For the last 3 years, researchers at UAPB and NWAC have been monitoring and verifying production yields in intensively aerated catfish ponds with aeration rates greater than 6 hp/acre. We now have three years of data on commercial catfish production in intensively aerated ponds. With stocking densi...

  3. Transition Strategies for Adolescents and Young Adults Who Use AAC. AAC Series

    ERIC Educational Resources Information Center

    McNaughton, David B., Ed.; Beukelman, David R., Ed.

    2010-01-01

    To make a smooth transition to a fulfilling, self-determined adult life, young people who use Augmentative-Alternative Communication (AAC) need effective services that meet their individual needs and make the most of advances in technology. Professionals will provide these critical supports with the help of this book, the first complete guide to…

  4. AAC assessment and clinical-decision making: the impact of experience.

    PubMed

    Dietz, Aimee; Quach, Wendy; Lund, Shelley K; McKelvey, Miechelle

    2012-09-01

    People with complex communication needs often require a comprehensive augmentative and alternative communication (AAC) assessment to maximize participation in daily interactions. Assessment of AAC is a complex process and limited practice guidelines exist. The purpose of this qualitative study was to explore how 25 speech-language pathologists with varying levels of experience approach the AAC assessment process. Participants were classified as either (a) General Practice Speech-Language Pathologists (GPSLPs), (b) AAC Clinical Specialists (AAC-CS), or (c) AAC Research/Policy Specialists (AAC-RS). In-depth, semi-structured interviews were conducted to explore the participants' approach to AAC assessment. The results revealed that GPSLPs approach AAC assessment differently than the AAC-CS and AAC-RS; however, the Specialists reported a similar approach that may help guide the development of practice guidelines for AAC assessment.

  5. AAC Strategies for Individuals with Moderate to Severe Disabilities

    ERIC Educational Resources Information Center

    Johnston, Susan S.; Reichle, Joe; Feeley, Kathleen M.; Jones, Emily A.

    2012-01-01

    With more children and young adults with severe disabilities in today's general education classrooms, SLPs and other professionals must be ready to support their students' communication skills with effective AAC. They'll get the proven strategies they need with this intervention guide from top AAC experts, ideal for use as an in-service…

  6. Adolescence and AAC: Intervention Challenges and Possible Solutions

    ERIC Educational Resources Information Center

    Smith, Martine M.

    2015-01-01

    Adolescence is a unique developmental period, spanning the gulf between childhood and adulthood. For adolescents who use augmentative and alternative communication (AAC), the major physical, cognitive, linguistic, social, and emotional changes associated with adolescence may have significant implications for their use of AAC. These challenges are…

  7. Learning to Use Augmentative and Alternative Communication (AAC): Is There a Mentoring Role for Adults Experienced in Using AAC?

    ERIC Educational Resources Information Center

    Ballin, Liora; Balandin, Susan; Togher, Leanne; Stancliffe, Roger J.

    2009-01-01

    Augmentative and alternative communication (AAC), including speech generating devices (SGDs), offer people with complex communication needs the potential for improved communication and participation in society. Despite rapid and ongoing development in AAC technology, its potential is not being fully realised. The number of people with complex…

  8. Aeration equipment for small depths

    NASA Astrophysics Data System (ADS)

    Sluše, Jan; Pochylý, František

    2015-05-01

    Deficit of air in water causes complications with cyanobacteria mainly in the summer months. Cyanobacteria is a bacteria that produces poison called cyanotoxin. When the concentration of cyanobacteria increases, the phenomena "algal bloom" appears, which is very toxic and may kill all the organisms. This article describes new equipment for aeration of water in dams, ponds and reservoirs with small depth. This equipment is mobile and it is able to work without any human factor because its control is provided by a GPS module. The main part of this equipment consists of a floating pump which pumps water from the surface. Another important part of this equipment is an aerator where water and air are blended. Final aeration process runs in the nozzles which provide movement of all this equipment and aeration of the water. Simulations of the flow are solved by multiphase flow with diffusion in open source program called OpenFOAM. Results will be verified by an experiment.

  9. Information for AAC Users (Augmentative and Alternative Communication)

    MedlinePlus

    ... people in the United States have a severe communication disorder that impairs their ability to talk. This ... worsening throughout life). Common causes of severe expressive communication disorders that may require the use of AAC ...

  10. Early Intervention and AAC: What a Difference 30 Years Makes.

    PubMed

    Romski, MaryAnn; Sevcik, Rose A; Barton-Hulsey, Andrea; Whitmore, Ani S

    2015-01-01

    This article provides an overview of early intervention and AAC over the 30-year period since the founding of the journal Augmentative and Alternative Communication in 1985. It discusses the global context for early intervention and addresses issues pertaining to young children from birth to 6 years of age. It provides a narrative review and synthesis of the evidence base in AAC and early intervention. Finally, it provides implications for practice and future research directions.

  11. Applying fine bubble aeration to small aeration tanks.

    PubMed

    Duchène, P; Cotteux, E; Capela, S

    2001-01-01

    Because the aeration system in an activated sludge plant typically represents a large part of the total energy requirements, designers and operators need accurate oxygen transfer information to make the aeration system as energy efficient as possible. This paper presents clean water tests performed at 38 wastewater treatment plants. The Specific Aeration Efficiency results (SAE, kgO2/kWh) are reported for: (1) large open channels (volume higher than 1000 m3), (2) small open channels, (3) total floor coverage cylindrical tanks, and (4) cylindrical tanks with a grid arrangement. Some practical guidelines can be drawn, some of them being: (1) high SAE can be achieved at small aeration tanks (< 1000 m3), applying cylindrical tanks with a total floor coverage arrangement of diffusers, volumetric blowers, and moderate air flow rates per diffuser area; (2) the high investment cost of this configuration can be justified with respect to a grid layout characterized by spiral liquid circulation which affects the oxygen transfer; (3) small open channels can meet sufficient SAE values but fail to meet in this range of tank volumes those of total floor coverage cylindrical tanks.

  12. How Concrete Is Concrete?

    ERIC Educational Resources Information Center

    Gravemeijer, Koeno

    2011-01-01

    If we want to make something concrete in mathematics education, we are inclined introduce, what we call, "manipulatives", in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own,…

  13. Water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels

    NASA Astrophysics Data System (ADS)

    Wang, Qingguo; Zhou, Xue; Zeng, Jinxia; Wang, Jizeng

    2016-02-01

    In this paper, the electron beam irradiation technology being more suitable for the industry application is explored to fabricate the acrylic acid (AAc) monomer-grafted polyvinyl alcohol (PVA-g-AAc) hydrogels. ATR-IR spectra of the PVA-g-AAc hydrogels shows an obvious absorption peak of the sbnd Cdbnd O group at 1701 cm-1, indicating that the AAc monomers were grafted onto the PVA macromolecules. This paper also studied some effects of the mass ratio of PVA/AAc, pH of buffer solution and irradiation dosage on the water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels. The water swelling ratio of PVA-g-AAc hydrogels decreases with increased irradiation dosage and mass ratio of PVA/AAc, whereas swelling ratio increases with increased pH of buffer solution and soaking time. The water-swelling behavior of PVA-g-AAc hydrogels occurred easily in an alkaline environment, particularly in a buffer solution with pH 9.2. Both PVA-g-AAc hydrogels (PVA/AAc = 1/5, w/w) irradiated with 5 kilogray (kGy) and PVA-g-AAc hydrogels (PVA/AAc = 1/1, w/w) irradiated with 15 kGy could easily absorb water and lead to high water swelling ratios (up to about 600%), which are potential candidates to meet the requirements for some biomedical applications.

  14. THE 13TH ADVANCED ACCELERATOR CONCEPTS WORKSHOP (AAC'8)

    SciTech Connect

    Leemans, Wim; Schroder, Carl B.; Esarey, Eric

    2008-07-15

    The Thirteenth Workshop on Advanced Accelerator Concepts (AAC) was held from July 27 to August 2, 2008 at the Chaminade Conference Center in Santa Cruz, California, USA, organized by the Lawrence Berkeley National Laboratory and the University of California at Berkeley. There were unprecedented levels of interest in the 2008 AAC Workshop, and participation was by invitation, with 215 workshop attendees, including 58 students. Reflecting the world-wide growth of the advanced accelerator community, there was significant international participation, with participants from twelve countries attending.

  15. AAC Language Activity Monitoring: Entering the New Millennium.

    ERIC Educational Resources Information Center

    Hill, Katya; Romich, Barry

    This report describes how augmentative and alternative communication (AAC) automated language activity monitoring can provide clinicians with the tools they need to collect and analyze language samples from the natural environment of children with disabilities for clinical intervention and outcomes measurements. The Language Activity Monitor (LAM)…

  16. Towards ontology personalization to enrich social conversations on AAC systems

    NASA Astrophysics Data System (ADS)

    Mancilla V., Daniela; Sastoque H., Sebastian; Iregui G., Marcela

    2015-01-01

    Communication is one of the essential needs of human beings. Augmentative and Alternative Communication Systems (AAC) seek to help in the generation of oral and written language to people with physical disorders that limit their natural communication. These systems present significant challenges such as: the composition of consistent messages according to syntactic and semantic rules, the improvement of message production times, the application to social contexts and, consequently, the incorporation of user-specific information. This work presents an original ontology personalization approach for an AAC instant messaging system incorporating personalized information to improve the efficacy and efficiency of the message production. This proposal is based on a projection of a general ontology into a more specific one, avoiding storage redundancy and data coupling, representing a big opportunity to enrich communication capabilities of current AAC systems. The evaluation was performed for a study case based on an AAC system for assistance in composing messages. The results show that adding user-specific information allows generation of enriched phrases, so improving the accuracy of the message, facilitating the communication process.

  17. Teaching Students with Developmental Disabilities to Locate Their AAC Device

    ERIC Educational Resources Information Center

    Sigafoos, Jeff; O'Reilly, Mark; Seely-York, Sue; Edrisinha, Chaturi

    2004-01-01

    Students with autism and related developmental disabilities who do not speak are often taught to use some type of augmentative and alternative communication (AAC) system, such as a voice output communication aid (VOCA). One problem with such devices is that the person may be unable to communicate when the device is not readily accessible. We first…

  18. AAC, Employment, and Independent Living: A Success Story

    ERIC Educational Resources Information Center

    Isakson, Carole L.; Burghstahler, Sheryl; Arnold, Anthony

    2006-01-01

    It has been well documented that individuals with significant physical disabilities who use augmentative and alternative communication (AAC) face considerable challenges in finding and maintaining employment. This article documents the experiences of one individual, Anthony Arnold, a young man who uses a Pathfinder[TM] for communication and a…

  19. Communication Partners Supporting Children with Complex Communication Needs Who Use AAC: A Systematic Review

    ERIC Educational Resources Information Center

    Shire, Stephanie Y.; Jones, Nancy

    2015-01-01

    Communication partners who efficiently use augmentative and alternative communication (AAC) are essential interaction partners for children learning to communicate using AAC. This systematic review examines studies targeting interventions designed to help communication partners support children with complex communication needs who use AAC.…

  20. [Ethylene oxide residues and aeration time after use of modern heated aerators (author's transl)].

    PubMed

    Star, E G

    1980-06-01

    The aeration time after ethylene oxide sterilization is rather long, particularly for PVC materials. It can be shortened enormously by heated aerators with continuous air exchange. We used different aeration methods and determined the ethylene oxide residues in endotracheal tubes, nasal and oro-pharyngeal airways, breathing tubes, parts of heart-lung-machines as well as gastroscope- and bronchoscope linings. The analyses were performed with a Hewlett-Packard gas chromatograph by the head space method. Intermittent vacuum with air irrigation was not as effective as continuous air exchange in heated aerators. The aeration time in these at 37 degrees C is longer than with 62 degrees C. After degassing in aerators with 62 degrees C the sterilized items can be used the next day already. Aerators blow the released ethylene oxide residues into the open air. The personnel is exposed to considerably smaller ethylene oxide concentrations because the long aeration time at room temperature in storage places is now eliminated.

  1. Aerated Lagoons. Student Manual. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Andersen, Lorri

    This student manual contains the textual material for a unit which focuses on the structural and operationally unique features of aerated lagoons. Topic areas discussed include: (1) characteristics of completely mixed aerated lagoons; (2) facultative aerated lagoons; (3) aerated oxidation ponds; (4) effects of temperature on aerated lagoons; (5)…

  2. High performance aerated lagoon systems

    SciTech Connect

    Rich, L.

    1999-08-01

    At a time when less money is available for wastewater treatment facilities and there is increased competition for the local tax dollar, regulatory agencies are enforcing stricter effluent limits on treatment discharges. A solution for both municipalities and industry is to use aerated lagoon systems designed to meet these limits. This monograph, prepared by a recognized expert in the field, provides methods for the rational design of a wide variety of high-performance aerated lagoon systems. Such systems range from those that can be depended upon to meet secondary treatment standards alone to those that, with the inclusion of intermittent sand filters or elements of sequenced biological reactor (SBR) technology, can also provide for nitrification and nutrient removal. Considerable emphasis is placed on the use of appropriate performance parameters, and an entire chapter is devoted to diagnosing performance failures. Contents include: principles of microbiological processes, control of algae, benthal stabilization, design for CBOD removal, design for nitrification and denitrification in suspended-growth systems, design for nitrification in attached-growth systems, phosphorus removal, diagnosing performance.

  3. Dissemination in Japan of multidrug-resistant Pseudomonas aeruginosa isolates producing IMP-type metallo-β-lactamases and AAC(6')-Iae/AAC(6')-Ib.

    PubMed

    Tojo, Masayoshi; Tada, Tatsuya; Shimojima, Masahiro; Tanaka, Masashi; Narahara, Kenji; Miyoshi-Akiyama, Tohru; Kirikae, Teruo; Ohmagari, Norio

    2014-09-01

    The spread throughout Japan of antibiotic-resistance factors in multidrug-resistant (MDR) Pseudomonas aeruginosa isolates was investigated epidemiologically, using immunochromatographic assays specific for IMP-type metallo-β-lactamases (IMPs) and aminoglycoside 6'-N-acetyltransferase [AAC(6')]-Iae and -Ib. Three hundred MDR P. aeruginosa isolates were obtained during each of two years, 2011 and 2012, from 190 hospitals in 39 prefectures in Japan. The percentage of P. aeruginosa isolates producing IMPs, AAC(6')-Iae or AAC(6')-Ib increased significantly from 170/300 (56.7%) in 2011 to 230/300 (76.7%) in 2012, with 134/170 (78.8%) in 2011 and 179/230 (77.8%) in 2012 producing both IMP and either AAC(6')-Iae or AAC(6')-Ib. The MICs of antibiotics, including cephalosporins and carbapenems, were markedly higher for isolates that did than did not produce these resistance factors. These results indicated that MDR P. aeruginosa producing IMPs, AAC(6')-Iae or AAC(6')-Ib have spread throughout Japan and that these antibiotic-resistance factors are useful markers for monitoring MDR P. aeruginosa in Japan.

  4. CuAAC: An Efficient Click Chemistry Reaction on Solid Phase.

    PubMed

    Castro, Vida; Rodríguez, Hortensia; Albericio, Fernando

    2016-01-11

    Click chemistry is an approach that uses efficient and reliable reactions, such as Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), to bind two molecular building blocks. CuAAC has broad applications in medicinal chemistry and other fields of chemistry. This review describes the general features and applications of CuAAC in solid-phase synthesis (CuAAC-SP), highlighting the suitability of this kind of reaction for peptides, nucleotides, small molecules, supramolecular structures, and polymers, among others. This versatile reaction is expected to become pivotal for meeting future challenges in solid-phase chemistry.

  5. Conductivity of p(AAc) Cryogel and Its Li+, Na+, and K+ Salts for NH3 Sensing

    NASA Astrophysics Data System (ADS)

    Sahiner, Nurettin; Demirci, Sahin; Sel, Kivanc

    2016-07-01

    Poly(acrylic acid) [p(AAc)] cryogel has been synthesized by a cryopolymerization technique under cryogenic conditions. The synthesized p(AAc) cryogel was treated with LiOH, NaOH, and KOH to generate corresponding salt forms of carboxylic acid groups within the p(AAc) cryogel network for activation as p(AAc)-Li+, p(AAc)-Na+, and p(AAc)-K+, respectively. The synthesized p(AAc)-based cryogels were characterized via Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The room-temperature electrical conductivity of the p(AAc), p(AAc)-Li+, p(AAc)-Na+, and p(AAc)-K+ cryogels was measured as 10-11 S cm-1, 10-10 S cm-1, 10-9 S cm-1, and 10-8 S cm-1, respectively. Furthermore, the p(AAc) cryogel and its salt forms were tested as sensor materials for NH3 gas by exposing them to NH3 vapor for 60 min under ambient conditions. Upon exposure to NH3 vapor, it was found that the conductivity of the bare p(AAc) and p(AAc)-K+ cryogels increased by up to 105- and 102-fold, respectively, compared with their NH3 unexposed states. The increase in conductivity for the other salt forms of p(AAc) cryogel was about 60-fold compared with their bare form. The conductivity increase for the p(AAc) and p(AAc)-K+ cryogels was therefore further investigated by changing the NH3 vapor exposure time, revealing that these materials could be used as sensors for NH3. It was further found that a 5 min NH3 gas exposure time was sufficient for p(AAc)-K+ cryogel to generate a detectable response via a change in the conductivity of the matrix.

  6. DESIGN INFORMATION ON FINE PORE AERATION SYSTEMS

    EPA Science Inventory

    Field studies were conducted over several years at municipal wastewater treatment plants employing line pore diffused aeration systems. These studies were designed to produce reliable information on the performance and operational requirements of fine pore devices under process ...

  7. ENHANCED BIODEGRADATION THROUGH IN-SITU AERATION

    EPA Science Inventory

    This presentation provided an overview of enhanced aerobic bioremediation using in-situ aeration or venting. The following topics were covered: (1) Basic discussion on biodegradation and respiration testing; (2) Basic discussion on volatilization, rate-limited mass transport, an...

  8. Oxygen transfer in circular surface aeration tanks.

    PubMed

    Rao, Achanta Ramakrishna; Patel, Ajey Kumar; Kumar, Bimlesh

    2009-06-01

    Surface aeration systems employed in activated sludge plants are the most energy-intensive units of the plants and typically account for a higher percentage of the treatment facility's total energy use. The geometry of the aeration tank imparts a major effect on the system efficiency. It is said that at optimal geometric conditions, systems exhibits the maximum efficiency. Thus the quantification of the optimal geometric conditions in surface aeration tanks is needed. Optimal geometric conditions are also needed to scale up the laboratory result to the field installation. In the present work, experimental studies have been carried out on baffled and unbaffled circular surface aeration tanks to ascertain the optimal geometric conditions. It is found that no optimal geometric conditions exist for the liquid/water depth in circular surface aeration tanks; however, for design purposes, a standard value has been assumed. Based on the optimal geometric conditions, a scale-up equation has been developed for the baffled circular surface aeration tanks.

  9. Challenge and Response: Integrity and AAC&U's Reform Initiatives, 1985-1994

    ERIC Educational Resources Information Center

    Schneider, Carol Geary

    2014-01-01

    Ten years ago, AAC&U (then AAC) issued a landmark report, "Integrity in the College Curriculum: A Report to the Academic Community". Anticipating the academy's sternest external critics by nearly a decade, "Integrity" offered a sweeping and incisive critique of curricular practice throughout higher education. "As for…

  10. An Investigation of the Efficacy of Direct and Indirect AAC Service Provision via Telepractice

    ERIC Educational Resources Information Center

    Hall, Nerissa C.

    2013-01-01

    There is a growing population of individuals using Augmentative and Alternative Communication (AAC) in need of evidence-based intervention from highly qualified personnel. However, not all speech pathology programs offer AAC coursework and/or practicum opportunities, and practicing speech-language pathologists (SLPs) report low levels of…

  11. Interaction of Participant Characteristics and Type of AAC with Individuals with ASD: A Meta-Analysis

    ERIC Educational Resources Information Center

    Ganz, Jennifer B.; Mason, Rose A.; Goodwyn, Fara D.; Boles, Margot B.; Heath, Amy K.; Davis, John L.

    2014-01-01

    Individuals with autism spectrum disorders (ASD) and complex communication needs often rely on augmentative and alternative communication (AAC) as a means of functional communication. This meta-analysis investigated how individual characteristics moderate effectiveness of three types of aided AAC: the Picture Exchange Communication System (PECS),…

  12. Keep Your Eye on the Prize: Implementing AAC within the Broader Context of Communicative Competence

    ERIC Educational Resources Information Center

    DeThorne, Laura Segebart; Hengst, Julie; Fisher, Kim; King, Amie

    2014-01-01

    Electronic technologies are playing an increasing role in mediating patterns of social interaction within the classroom. This trend includes augmentative and alternative communication (AAC) systems like light-weight smart tablets. AAC in general has proven effective for many children in regard to decreasing challenging behavior, enabling…

  13. AAC Modeling with the iPad during Shared Storybook Reading Pilot Study

    ERIC Educational Resources Information Center

    Sennott, Samuel C.; Mason, Linda H.

    2016-01-01

    This pilot study describes an intervention package, MODELER for Read and Talk, designed to provide enriched language interaction for children with complex communication needs who require augmentative and alternative communication (AAC). MODELER (Model, Encourage, Respond) includes (a) modeling AAC as you speak, (b) encouraging communication…

  14. The Influence of AAC Device Type, Dynamic vs. Static Screen, on Peer Attitudes

    ERIC Educational Resources Information Center

    Dudek, Karen; Beck, Ann R.; Thompson, James R.

    2006-01-01

    This study examined how children's attitudes toward a peer who used augmentative and alternative communication (AAC) were influenced by type of AAC device accessed by the child for communication. Specifically, the influence of dynamic screens vs. static screens was investigated. Two videotapes were created. In one a child used a dynamic screen…

  15. Literacy learning in users of AAC: A neurocognitive perspective.

    PubMed

    Van Balkom, Hans; Verhoeven, Ludo

    2010-09-01

    The understanding of written or printed text or discourse - depicted either in orthographical, graphic-visual or tactile symbols - calls upon both bottom-up word recognition processes and top-down comprehension processes. Different architectures have been proposed to account for literacy processes. Research has shown that the first steps in perceiving, processing and deriving conceptual meaning from words, graphic symbols, manual signs, and co-speech gestures or tactile manual signing and tangible symbols can be seen as identical and collectively (sub)activated. Results from recent brain research and neurolinguistics have revealed new insights in the reading process of typical and atypical readers and may provide verifiable evidence for improved literacy assessment and the validation of early intervention programs for AAC users. PMID:20874078

  16. Developing AAC technologies: a personal story and philosophy.

    PubMed

    Newell, A F; Alm, N

    1994-01-01

    Research into and development of augmentative and alternative communication (AAC) technologies is an exciting but complex field. The development of a technologically based system which will be an alternative to, or will augment, the speech modality for the interpersonal communication needs of people with communication dysfunction is not an easy task. This is only a young field and thus much of the research methodology is not yet well defined. It is also a growing field, and one to which we would wish to attract new practitioners, and provide appropriate guidance to them. In any technological development project, it is important to define clearly a number of parameters of the project. These are: the client group; the knowledge base needed to solve the problems; the potential technologies that will help and their characteristics; and the time scales envisaged for completion of the research. The authors have been part of a research team working in this field for many years, and, in this paper, they will examine three research strategies which they have found particularly beneficial, illustrating the concepts discussed mainly by reference to personal experiences. The paper concentrates on a relatively narrow definition of technology-that which is often referred to as 'high technology' or information technology. This is not to deny, in any way, the importance to the AAC field of solutions based on other technology, and the authors would hope that some of the comments in the paper are also appropriate to researchers who are working with systems and techniques which do not depend on these technologies.

  17. Soil Aeration deficiencies in urban sites

    NASA Astrophysics Data System (ADS)

    Weltecke, Katharina; Gaertig, Thorsten

    2010-05-01

    Soil aeration deficiencies in urban sites Katharina Weltecke and Thorsten Gaertig On urban tree sites reduction of soil aeration by compaction or sealing is an important but frequently underestimated factor for tree growth. Up to 50% of the CO2 assimilated during the vegetation period is respired in the root space (Qi et al. 1994). An adequate supply of the soil with oxygen and a proper disposal of the exhaled carbon dioxide are essential for an undisturbed root respiration. If the soil surface is smeared, compacted or sealed, soil aeration is interrupted. Several references show that root activity and fine root growth are controlled by the carbon dioxide concentration in soil air (Qi et al.1994, Burton et al. 1997). Gaertig (2001) found that decreasing topsoil gas permeability leads to reduced fine root density and hence to injury in crown structure of oaks. In forest soils a critical CO2 concentration of more than 0.6 % indicates a bad aeration status (Gaertig 2001). The majority of urban tree sites are compacted or sealed. The reduction of soil aeration may lead to dysfunctions in the root space and consequently to stress during periods of drought, which has its visible affects in crown structure. It is reasonable to assume that disturbances in soil aeration lead to reduced tree vigour and roadworthiness, resulting in high maintenance costs. The assessment of soil aeration in urban sites is difficult. In natural ecosystems the measurement of gas diffusivity and the gas-chromatical analysis of CO2 in soil air are accepted procedures in analyzing the state of aeration (Schack-Kirchner et al. 2001, Gaertig 2001). It has been found that these methods can also be applied for analyzing urban sites. In particular CO2 concentration in the soil atmosphere can be considered as a rapidly assessable, relevant and integrating indicator of the aeration situation of urban soils. This study tested the working hypothesis that soil aeration deficiencies lead to a decrease of fine

  18. Landfill aeration worldwide: Concepts, indications and findings

    SciTech Connect

    Ritzkowski, M.; Stegmann, R.

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer Different landfill aeration concepts and accordant application areas are described. Black-Right-Pointing-Pointer Examples of full scale projects are provided for Europe, North-America and Asia. Black-Right-Pointing-Pointer Major project findings are summarised, including prospects and limitations. Black-Right-Pointing-Pointer Inconsistencies between laboratory and full scale results have been elaborated. Black-Right-Pointing-Pointer An explanatory approach in connection with the inconsistencies is provided. - Abstract: The creation of sustainable landfills is a fundamental goal in waste management worldwide. In this connection landfill aeration contributes towards an accelerated, controlled and sustainable conversion of conventional anaerobic landfills into a biological stabilized state associated with a minimised emission potential. The technology has been successfully applied to landfills in Europe, North America and Asia, following different strategies depending on the geographical region, the specific legislation and the available financial resources. Furthermore, methodologies for the incorporation of landfill aeration into the carbon trade mechanisms have been developed in recent years. This manuscript gives an overview on existing concepts for landfill aeration; their application ranges and specifications. For all of the described concepts examples from different countries worldwide are provided, including details regarding their potentials and limitations. Some of the most important findings from these aeration projects are summarised and future research needs have been identified. It becomes apparent that there is a great demand for a systematisation of the available results and implications in order to further develop and optimise this very promising technology. The IWWG (International Waste Working Group) Task Group 'Landfill Aeration' contributes towards the achievement of this goal.

  19. Acid mine water aeration and treatment system

    DOEpatents

    Ackman, Terry E.; Place, John M.

    1987-01-01

    An in-line system is provided for treating acid mine drainage which basically comprises the combination of a jet pump (or pumps) and a static mixer. The jet pump entrains air into the acid waste water using a Venturi effect so as to provide aeration of the waste water while further aeration is provided by the helical vanes of the static mixer. A neutralizing agent is injected into the suction chamber of the jet pump and the static mixer is formed by plural sections offset by 90 degrees.

  20. Surfactant effects on alpha-factors in aeration systems.

    PubMed

    Rosso, Diego; Stenstrom, Michael K

    2006-04-01

    Aeration in wastewater treatment processes accounts for the largest fraction of plant energy costs. Aeration systems function by shearing the surface (surface aerators) or releasing bubbles at the bottom of the tank (coarse- or fine-bubble aerators). Surfactant accumulation on gas-liquid interfaces reduces mass transfer rates, and this reduction in general is larger for fine-bubble aerators. This study evaluates mass transfer effects on the characterization and specification of aeration systems in clean and process water conditions. Tests at different interfacial turbulence regimes show higher gas transfer depression for lower turbulence regimes. Contamination effects can be offset at the expense of operating efficiency, which is characteristic of surface aerators and coarse-bubble diffusers. Results describe the variability of alpha-factors measured at small scale, due to uncontrolled energy density. Results are also reported in dimensionless empirical correlations describing mass transfer as a function of physiochemical and geometrical characteristics of the aeration process. PMID:16549087

  1. Characterization of Tn6238 with a New Allele of aac(6′)-Ib-cr

    PubMed Central

    Quiroga, María P.; Orman, Betina; Errecalde, Laura; Kaufman, Sara

    2015-01-01

    Here, we report that the genetic structure of Tn1331 remained conserved in Argentina from 1989 to 2013 (72 of 73 isolates), with the exception being the plasmid-borne Tn1331-like transposon Tn6238 containing a new aac(6′)-Ib-cr allele recovered from a colistin-resistant Klebsiella pneumoniae clinical isolate. A bioinformatic analysis of aac(6′)-Ib-like gene cassettes suggests that this new aac(6′)-Ib-cr allele emerged through mutation or homologous recombination in the Tn1331 genetic platform. Tn6238 is a novel platform for the dissemination of aminoglycoside and fluoroquinolone resistance determinants. PMID:25691640

  2. Evaluation of oxygen transfer parameters of fine-bubble aeration system in plug flow aeration tank of wastewater treatment plant.

    PubMed

    Zhou, Xiaohong; Wu, Yuanyuan; Shi, Hanchang; Song, Yanqing

    2013-02-01

    Knowledge of the oxygen mass transfer of aerators under operational conditions in a full-scale wastewater treatment plant (WWTP) is meaningful for the optimization of WWTP, however, scarce to best of our knowledge. Through analyzing a plug flow aeration tank in the Lucun WWTP, in Wuxi, China, the oxygenation capacity of fine-bubble aerators under process conditions have been measured in-situ using the off-gas method and the non-steady-state method. The off-gas method demonstrated that the aerators in different corridors in the aeration tank of WWTP ha d significantly different oxygen transferperformance; furthermore, the aerators in the samecorridor shared almost equal oxygen transfer performance over the course of a day. Results measured by the two methods showed that the oxygen transfer performance of fine-bubble aerators in the aeration tank decreased dramatically compared with that in the clean water. The loss of oxygen transfer coefficient was over 50% under low-aeration conditions (aeration amount < 0.67 Nm3/hr). However, as the aeration amount reached 0.96 Nm3/hr, the discrepancy of oxygen transfer between the process condition and clean water was negligible. The analysis also indicated that the non-steady-state and off-gas methods resulted in comparable estimates of oxygen transfer parameters for the aerators under process conditions.

  3. At-Home Learning and AAC Solutions Are All in the Details

    ERIC Educational Resources Information Center

    Murphy, Patti

    2010-01-01

    Home-based learning involves juggling many realities to bring out the abilities of medically fragile students. Many homebound learners use augmentative and alternative communication (AAC) for self-expression. This article provides a glimpse of what this means.

  4. AAC and Early Intervention for Children with Cerebral Palsy: Parent Perceptions and Child Risk Factors.

    PubMed

    Smith, Ashlyn L; Hustad, Katherine C

    2015-01-01

    The current study examined parent perceptions of communication, the focus of early intervention goals and strategies, and factors predicting the implementation of augmentative and alternative communication (AAC) for 26 two-year-old children with cerebral palsy. Parents completed a communication questionnaire and provided early intervention plans detailing child speech and language goals. Results indicated that receptive language had the strongest association with parent perceptions of communication. Children who were not talking received a greater number of intervention goals, had a greater variety of goals, and had more AAC goals than children who were emerging and established talkers. Finally, expressive language had the strongest influence on AAC decisions. Results are discussed in terms of the relationship between parent perceptions and language skills, communication as an emphasis in early intervention, AAC intervention decisions, and the importance of receptive language. PMID:26401966

  5. Copper catalysed azide-alkyne cycloaddition (CuAAC) in liquid ammonia.

    PubMed

    Ji, Pengju; Atherton, John H; Page, Michael I

    2012-10-21

    Copper(I) catalysed azide-alkyne cycloaddition reactions (CuAAC) occur smoothly in liquid ammonia (LNH(3)) at room temperature to give exclusively 1,4-substituted 1,2,3-triazoles with excellent yields (up to 99%). The CuAAC reactions in liquid ammonia require relatively small amounts of copper(I) catalyst (0.5 mole%) compared with that in conventional solvents. The product can be obtained conveniently by simply evaporation of ammonia, indicating its potential application in industry. The rate of the CuAAC reaction in liquid ammonia shows a second order dependence on the copper(I) concentration and the reaction occurs only with terminal alkynes. Deuterium exchange experiments with phenyl acetylene-d(1) show that the acidity of the alkyne is increased at least 1000-fold with catalytic amounts of copper(I) in liquid ammonia. The mechanism of the CuAAC reaction in liquid ammonia is discussed. PMID:22930181

  6. Peer-Mediated AAC Instruction for Young Children with Autism and other Developmental Disabilities

    PubMed Central

    Thiemann-Bourque, Kathy

    2013-01-01

    Many young children with developmental disabilities (DD) have significant delays in social, communication, and play skills. For those children learning to use augmentative and alternative communication (.AAC% successful social interactions with peers will require explicit instruction on the same system for both communication partners. Peer-mediated (PM) interventions are recommended best practice based on more than 30 years of research with young children with autism and other DDs. Integrating direct AAC instruction within PM programs to advance social reciprocity in typical preschool routines is a necessary and important next step for young AAC users. In this article, I will summarize the design and outcomes of two PM AAC studies documenting positive social outcomes for preschool children with severe autism. I will also teach} peer partners how to use AAC highlight strategies to recruit peers without disabilities systems (e.g., Picture Exchange Communication System [PECS], Speech Generating Devices [SGDs]), and engineer the preschool classroom for successful AAC communication. I will describe data collection procedures for measuring changes in reciprocal child and peer social communication interactions. PMID:24392179

  7. Is Awesome Really Awesome? How the Inclusion of Informal Terms on an AAC Device Influences Children's Attitudes toward Peers Who Use AAC

    ERIC Educational Resources Information Center

    Beck, Ann R.; Bock, Stacey; Thompson, James R.; Bowman, Linda; Robbins, Stacey

    2006-01-01

    Two videotapes were created of a child communicating with a voice output augmentative and alternative communication (AAC) device. In one the child communicated using formal English only and in the other the child communicated using formal English and age appropriate informal terms. Children in grades 4 and 5 viewed either the formal English only…

  8. Bacterial concrete

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, Venkataswamy; Ramesh, K. P.; Bang, S. S.

    2001-04-01

    Cracks in concrete are inevitable and are one of the inherent weaknesses of concrete. Water and other salts seep through these cracks, corrosion initiates, and thus reduces the life of concrete. So there was a need to develop an inherent biomaterial, a self-repairing material which can remediate the cracks and fissures in concrete. Bacterial concrete is a material, which can successfully remediate cracks in concrete. This technique is highly desirable because the mineral precipitation induced as a result of microbial activities is pollution free and natural. As the cell wall of bacteria is anionic, metal accumulation (calcite) on the surface of the wall is substantial, thus the entire cell becomes crystalline and they eventually plug the pores and cracks in concrete. This paper discusses the plugging of artificially cracked cement mortar using Bacillus Pasteurii and Sporosarcina bacteria combined with sand as a filling material in artificially made cuts in cement mortar which was cured in urea and CaCl2 medium. The effect on the compressive strength and stiffness of the cement mortar cubes due to the mixing of bacteria is also discussed in this paper. It was found that use of bacteria improves the stiffness and compressive strength of concrete. Scanning electron microscope (SEM) is used to document the role of bacteria in microbiologically induced mineral precipitation. Rod like impressions were found on the face of calcite crystals indicating the presence of bacteria in those places. Energy- dispersive X-ray (EDX) spectra of the microbial precipitation on the surface of the crack indicated the abundance of calcium and the precipitation was inferred to be calcite (CaCO3).

  9. CFD model of an aerating hydrofoil

    NASA Astrophysics Data System (ADS)

    Scott, D.; Sabourin, M.; Beaulieu, S.; Papillon, B.; Ellis, C.

    2014-03-01

    Improving water quality in the tailrace below hydroelectric dams has become a priority in many river systems. In warm climates, water drawn by the turbine from deep in a reservoir can be deficient in dissolved oxygen (DO), a critical element in maintaining a healthy aquatic ecosystem. Many different solutions have been proposed in order to increase the DO levels in turbine discharge, including: turbine aeration systems (adding air to the water through either the turbine hub, the periphery or through distributed aeration in the runner blades); bubble diffusers in the reservoir or in the tailrace; aerating weirs downstream of the dams; and surface water pumps in the reservoir near the dam. There is a significant potential to increase the effectiveness of these solutions by improving the way that oxygen is introduced into the water; better distributions of bubbles will result in better oxygen transfer. In the present study, a two-phase Computational Fluid Dynamics model has been formulated using a commercial code to study the distribution of air downstream of a simple aerating hydrofoil. The two-phase model uses the Eulerian-Eulerian approach. Appropriate relations are used to model the interphase forces, including the Grace drag force model, the Favre averaged drag force and the Sato enhanced eddy viscosity. The model is validated using experimental results obtained in the water tunnel at the University of Minnesota's Saint Anthony Falls Laboratory. Results are obtained for water velocities between 5 and 10 m/s, air flow rates between 0.5 and 1.5 sL/min and for angles of attack between 0° and -8°. The results of this study show that the CFD model provides a good qualitative comparison to the experimental results by well predicting the wake location at the different flow rates and angles of attack used.

  10. Effects of aeration method and aeration rate on greenhouse gas emissions during composting of pig feces in pilot scale.

    PubMed

    Jiang, Tao; Li, Guoxue; Tang, Qiong; Ma, Xuguang; Wang, Gang; Schuchardt, Frank

    2015-05-01

    The aim of this study was to uncover ways to mitigate greenhouse gas (GHG) emissions and reduce energy consumption during the composting process. We assessed the effects of different aeration rates (0, 0.18, 0.36, and 0.54 L/(kg dry matter (dm)·min)) and methods (continuous and intermittent) on GHG emissions. Pig feces and corn stalks were mixed at a ratio of 7:1. The composting process lasted for 10 weeks, and the compost was turned approximately every 2 weeks. Results showed that both aeration rate and method significantly affected GHG emissions. Higher aeration rates increased NH3 and N2O losses, but reduced CH4 emissions. The exception is that the CH4 emission of the passive aeration treatment was lower than that of the low aeration rate treatment. Without forced aeration, the CH4 diffusion rates in the center of the piles were very low and part of the CH4 was oxidized in the surface layer. Intermittent aeration reduced NH3 and CH4 losses, but significantly increased N2O production during the maturing periods. Intermittent aeration increased the nitrification/denitrification alternation and thus enhanced the N2O production. Forced aeration treatments had higher GHG emission rates than the passive aeration treatment. Forced aeration accelerated the maturing process, but could not improve the quality of the end product. Compared with continuous aeration, intermittent aeration could increase the O2 supply efficiency and reduced the total GHG emission by 17.8%, and this reduction increased to 47.4% when composting was ended after 36 days. PMID:25968266

  11. Effects of aeration method and aeration rate on greenhouse gas emissions during composting of pig feces in pilot scale.

    PubMed

    Jiang, Tao; Li, Guoxue; Tang, Qiong; Ma, Xuguang; Wang, Gang; Schuchardt, Frank

    2015-05-01

    The aim of this study was to uncover ways to mitigate greenhouse gas (GHG) emissions and reduce energy consumption during the composting process. We assessed the effects of different aeration rates (0, 0.18, 0.36, and 0.54 L/(kg dry matter (dm)·min)) and methods (continuous and intermittent) on GHG emissions. Pig feces and corn stalks were mixed at a ratio of 7:1. The composting process lasted for 10 weeks, and the compost was turned approximately every 2 weeks. Results showed that both aeration rate and method significantly affected GHG emissions. Higher aeration rates increased NH3 and N2O losses, but reduced CH4 emissions. The exception is that the CH4 emission of the passive aeration treatment was lower than that of the low aeration rate treatment. Without forced aeration, the CH4 diffusion rates in the center of the piles were very low and part of the CH4 was oxidized in the surface layer. Intermittent aeration reduced NH3 and CH4 losses, but significantly increased N2O production during the maturing periods. Intermittent aeration increased the nitrification/denitrification alternation and thus enhanced the N2O production. Forced aeration treatments had higher GHG emission rates than the passive aeration treatment. Forced aeration accelerated the maturing process, but could not improve the quality of the end product. Compared with continuous aeration, intermittent aeration could increase the O2 supply efficiency and reduced the total GHG emission by 17.8%, and this reduction increased to 47.4% when composting was ended after 36 days.

  12. AAC to Support Conversation in Persons with Moderate Alzheimer’s Disease

    PubMed Central

    FRIED-OKEN, MELANIE; ROWLAND, CHARITY; DANIELS, DARLENE; DIXON, MAYLING; FULLER, BRET; MILLS, CAROLYN; NOETHE, GLORY; SMALL, JEON; STILL, KEVIN; OKEN, BARRY

    2013-01-01

    Even though we know that external memory aids support communication in Alzheimer’s disease, the components of the communication aids for individuals with Alzheimer’s disease have not been studied systematically. The goal of these two pilot experiments was to examine differences in conversational performance of adults with Alzheimer’s disease related to the presence and absence of an aid, the type of symbol embedded in the aid, and the presence or absence of voice output. In Experiment 1, 30 adults with moderate-to-severe Alzheimer’s disease participated in 10-min conversations with and without personalized AAC boards. There was no effect of AAC, regardless of symbol type, and a deleterious effect of voice output. In Experiment 2, modified spaced-retrieval training preceded conversations, standardized prompts were presented, and semantically-based dependent variables were examined. For the 11 participants in the second experiment, there was a significant effect of AAC, showing that the presence of AAC was associated with greater use of targeted words during personal conversations. We discuss new information about the contribution of AAC for persons with Alzheimer’s disease, and demonstrate how the applied research process evolves over the course of a long-term commitment to a scientific investigation. PMID:23256854

  13. Effects of AAC interventions on communication and language for young children with complex communication needs.

    PubMed

    Drager, Kathryn; Light, Janice; McNaughton, David

    2010-01-01

    Children with complex communication needs (CCN) who require augmentative and alternative communication (AAC) are at considerable risk in many aspects of their development: (a) functional communication skills, (b) speech development, (c) language development, (d) cognitive/conceptual development, (e) literacy development, (f) social participation, (g) access to education, and (h) overall quality of life. Early intervention is critical to address these areas and provide successful and functional outcomes. AAC offers the potential to enhance communication, language, and learning for children with significant communication disabilities. This paper provides an overview of the effects of AAC interventions on communication, behavior, language, and speech outcomes for young children with CCN for pediatricians and other medical and rehabilitation professionals. Future research directions to maximize the communication development of young children with CCN are also discussed. PMID:21791864

  14. Tracer studies on an aerated lagoon.

    PubMed

    Broughton, Alistair; Shilton, Andy

    2012-01-01

    The city of Palmerston North, New Zealand, has two aerated lagoons as its secondary treatment facility. Interest about treatment efficiency led to an investigation into the hydraulics in the second lagoon to determine if further optimisation was viable. A tracer study using rhodamine WT was undertaken to ascertain the stimulus response output. Samples were also taken at 24 points within the lagoon to determine the tracer concentration profile throughout the lagoon. The mean residence time was determined to be 39.9 h compared with a theoretical residence time of 55.4 h. Peak concentration of the tracer at the outlet occurred at 0.44 of the mean residence time. The results of the tracer study pointed to 28% of volume being dead space. A subsequent sludge survey indicated that 26% of the design volume of the lagoon was filled with sludge. While the curved geometry of the lagoon did not appear to impact the hydraulics the fact that the first aerator is confined in a relatively smaller area will have locally boosted the mixing energy input in this inlet zone. From interpretation of the tracer response and the tracer distribution profiles it appears that the aerators are mixing the influent into the bulk flow effectively in the front end of the lagoon and that there was no evidence of any substantive short-circuiting path of concentrated tracer around to the outlet. The tracer distribution profiles gave direct insight as to how the tracer was being transported within the pond and should be used more often when conducting tracer studies. Comparison with the literature indicated that the lagoon's hydraulic efficiency was on par with a baffled pond system and it would be expected that addition of several baffles to the lagoon would provide minimal further improvement. PMID:22277219

  15. Municipal sludge characteristic changes under different aerating condition in a deep-shaft aeration system.

    PubMed

    Xiong, Jiaqing; Wang, Xiaochang C; Shu, Wei; He, Teng; Liu, Yanzheng

    2016-01-01

    A pilot-scale municipal sewage sludge deep-shaft aeration system was implemented in Lanzhou, Gansu Province of China. The reactor depth was 60 m with a diameter of 1.0 m and the sludge to be treated came from a wastewater plant in Lanzhou. In order to obtain the optimum operation conditions, analysis was conducted on the transformations of the volatile suspended solids (VSS), temperature, pH, oxidation-reduction potential (ORP) and pathogens in the deep-shaft reactor under different aeration conditions. Attention was paid to how operating conditions affected the removal efficiency of the VSS and the reaction temperature. As a result, higher volatile solids removal was gained at higher temperature, and the temperature could reach 50.8°C for a complete inactivation of bacteria in the first reaction zone when the deep-shaft aeration system was run for about 18 days. The sludge aeration rate was observed as 1.5 to 1.8 L/(h·L sludge) which enabled the volatile solids removal rate to reach 40.1%. The degradation of VSS occurred under a micro-oxygen environment, and the lowest ORP was found to be -256 mV in the digestive process. Not only aerobic bacteria but also anaerobic and facultative bacteria performed their functions in the reactor.

  16. Municipal sludge characteristic changes under different aerating condition in a deep-shaft aeration system.

    PubMed

    Xiong, Jiaqing; Wang, Xiaochang C; Shu, Wei; He, Teng; Liu, Yanzheng

    2016-01-01

    A pilot-scale municipal sewage sludge deep-shaft aeration system was implemented in Lanzhou, Gansu Province of China. The reactor depth was 60 m with a diameter of 1.0 m and the sludge to be treated came from a wastewater plant in Lanzhou. In order to obtain the optimum operation conditions, analysis was conducted on the transformations of the volatile suspended solids (VSS), temperature, pH, oxidation-reduction potential (ORP) and pathogens in the deep-shaft reactor under different aeration conditions. Attention was paid to how operating conditions affected the removal efficiency of the VSS and the reaction temperature. As a result, higher volatile solids removal was gained at higher temperature, and the temperature could reach 50.8°C for a complete inactivation of bacteria in the first reaction zone when the deep-shaft aeration system was run for about 18 days. The sludge aeration rate was observed as 1.5 to 1.8 L/(h·L sludge) which enabled the volatile solids removal rate to reach 40.1%. The degradation of VSS occurred under a micro-oxygen environment, and the lowest ORP was found to be -256 mV in the digestive process. Not only aerobic bacteria but also anaerobic and facultative bacteria performed their functions in the reactor. PMID:27054720

  17. A CuAAC-Hydrazone-CuAAC Trifunctional Scaffold for the Solid-Phase Synthesis of Trimodal Compounds: Possibilities and Limitations.

    PubMed

    Fabre, Benjamin; Pícha, Jan; Vaněk, Václav; Buděšínský, Miloš; Jiráček, Jiří

    2015-10-23

    We present a trifunctional scaffold designed for the solid-phase synthesis of trimodal compounds. This scaffold holds two alkyne arms in a free and TIPS-protected form for consecutive CuAAC (copper(I)-catalyzed azide-alkyne cycloaddition), one Fmoc-protected hydrazide arm for reaction with aldehydes, and one carboxylic acid arm with CF₂ groups for attachment to the resin and (19)F-NMR quantification. This scaffold was attached to a resin and derivatized with model azides and aliphatic, electron-rich or electron-poor aromatic aldehydes. We identified several limitations of the scaffold caused by the instability of hydrazones in acidic conditions, in the presence of copper during CuAAC, and when copper accumulated in the resin. We successfully overcame these drawbacks by optimizing synthetic conditions for the derivatization of the scaffold with aromatic aldehydes. Overall, the new trifunctional scaffold combines CuAAC and hydrazone chemistries, offering a broader chemical space for the development of bioactive compounds.

  18. Support for AAC Use in Preschool, and Growth in Language Skills, for Young Children with Developmental Disabilities

    PubMed Central

    BARKER, R. MICHAEL; AKABA, SANAE; BRADY, NANCY C.; THIEMANN-BOURQUE, KATHY

    2014-01-01

    Little is known about how AAC use in preschool may impact language development for children with complex communication needs (e.g., children with autism, cerebral palsy, Down syndrome, and other developmental disabilities). We developed two surveys (a) to describe children’s use of AAC in preschool classrooms, as well as the use of prompts and question asking, and augmented input by their communication partners; and (b) to describe teachers’ experience, training, and perceived support in providing AAC. We then examined the relationship between children’s experience of AAC, including the use of prompts, question asking, and augmented input by their partners, and the growth of receptive and expressive language for 71 children with developmental disabilities over a two-year period. The use of AAC by peers to provide augmented input was associated with stronger language growth; the use of prompting and question asking by teachers was associated with weaker language growth. Teachers reported that they received little training regarding ways to support a child’s use of AAC. Results suggest the need for further research on promoting AAC use at the preschool level, including research to promote peer interactions for AAC users. PMID:24229337

  19. Aeration control of thermophilic aerobic digestion using fluorescence monitoring.

    PubMed

    Kim, Young-Kee; Oh, Byung-Keun

    2009-01-01

    The thermophilic aerobic digestion (TAD) process is recognized as an effective method for rapid waste activated sludge (WAS) degradation and the deactivation of pathogenic microorganisms. Yet, high energy costs due to heating and aeration have limited the commercialization of economical TAD processes. Previous research on autothermal thermophilic aerobic digestion (ATAD) has already reduced the heating cost. However, only a few studies have focused on reducing the aeration cost. Therefore, this study applied a two-step aeration control strategy to a fill-and-draw mode semicontinuous TAD process. The NADH-dependent fluorescence was monitored throughout the TAD experiment, and the aeration rate shifted according to the fluorescence intensity. As a result, the simple two-step aeration control operation achieved a 20.3% reduction in the total aeration, while maintaining an effective and stable operation. It is also expected that more savings can be achieved with a further reduction of the lower aeration rate or multisegmentation of the aeration rate. PMID:19190414

  20. Enhancement of ultrasonic disintegration of sewage sludge by aeration.

    PubMed

    Zhao, He; Zhang, Panyue; Zhang, Guangming; Cheng, Rong

    2016-04-01

    Sonication is an effective way for sludge disintegration, which can significantly improve the efficiency of anaerobic digestion to reduce and recycle use of sludge. But high energy consumption limits the wide application of sonication. In order to improve ultrasonic sludge disintegration efficiency and reduce energy consumption, aeration was introduced. Results showed that sludge disintegration efficiency was improved significantly by combining aeration with ultrasound. The aeration flow rate, gas bubble size, ultrasonic density and aeration timing had impacts on sludge disintegration efficiency. Aeration that used in later stage of ultrasonic irradiation with low aeration flow rate, small gas bubbles significantly improved ultrasonic disintegration sludge efficiency. At the optimal conditions of 0.4 W/mL ultrasonic irradiation density, 30 mL/min of aeration flow rate, 5 min of aeration in later stage and small gas bubbles, ultrasonic sludge disintegration efficiency was increased by 45% and one third of ultrasonic energy was saved. This approach will greatly benefit the application of ultrasonic sludge disintegration and strongly promote the treatment and recycle of wastewater sludge. PMID:27090707

  1. OXIDATION OF AS(III) BY AERATION AND STORAGE

    EPA Science Inventory

    A study of the effects of aeration and storage on the oxidation of arsenic(III) was undertaken at three utilities in the US to establish the engineering significance of aeration as a potential pre-treatment method for arsenic removal. The results of this study clearly establish t...

  2. Enhancement of ultrasonic disintegration of sewage sludge by aeration.

    PubMed

    Zhao, He; Zhang, Panyue; Zhang, Guangming; Cheng, Rong

    2016-04-01

    Sonication is an effective way for sludge disintegration, which can significantly improve the efficiency of anaerobic digestion to reduce and recycle use of sludge. But high energy consumption limits the wide application of sonication. In order to improve ultrasonic sludge disintegration efficiency and reduce energy consumption, aeration was introduced. Results showed that sludge disintegration efficiency was improved significantly by combining aeration with ultrasound. The aeration flow rate, gas bubble size, ultrasonic density and aeration timing had impacts on sludge disintegration efficiency. Aeration that used in later stage of ultrasonic irradiation with low aeration flow rate, small gas bubbles significantly improved ultrasonic disintegration sludge efficiency. At the optimal conditions of 0.4 W/mL ultrasonic irradiation density, 30 mL/min of aeration flow rate, 5 min of aeration in later stage and small gas bubbles, ultrasonic sludge disintegration efficiency was increased by 45% and one third of ultrasonic energy was saved. This approach will greatly benefit the application of ultrasonic sludge disintegration and strongly promote the treatment and recycle of wastewater sludge.

  3. FOULING OF FINE PORE DIFFUSED AERATORS: AN INTER- PLANT COMPARISON

    EPA Science Inventory

    There has been increasing interest in fine pore aeration systems, along with concerned about diffuser fouling and the subsequent loss of aeration efficiency. The objective of this study was to assess the relative fouling tendency of fine bubble diffusers t nine activated sludge ...

  4. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... sterilization. The device may include a heater to warm the circulating air. (b) Classification. Class...

  5. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  6. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  7. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  8. Recirculation-aeration: Bibliography for aquaculture. Bibliographies and literature of agriculture (Final)

    SciTech Connect

    Perschbacher, P.W.; Powell, R.V.; Freeman, D.W.; Lorio, W.J.; Hanfman, D.T.

    1993-08-01

    The bibliography includes literature citations through 1992 related to water recirculation and aeration in aquaculture. The focus is on filtration, aeration, and circulation techniques in various aquaculture situations.

  9. Use and Acceptance of AAC Systems by Children with Angelman Syndrome

    ERIC Educational Resources Information Center

    Calculator, Stephen N.

    2013-01-01

    Background: This investigation of children with Angelman syndrome (AS) examined reported uses of electronic augmentative and alternative communication (AAC) devices (i.e. VOCAs), including speech generating devices, in relation to other aided and unaided methods of communication. Materials and Method: A total of 122 parents of children with AS,…

  10. Discovery of bioactive molecules from CuAAC click-chemistry-based combinatorial libraries.

    PubMed

    Wang, Xueshun; Huang, Boshi; Liu, Xinyong; Zhan, Peng

    2016-01-01

    The rapid assembly and in situ screening of focused combinatorial fragment libraries using CuAAC click chemistry is a highly robust and efficient strategy for establishing SAR and for discovering bioactive molecules. This review outlines the current status of this methodology in drug discovery application. The inherent limitations, challenges and prospects are critically discussed. PMID:26315392

  11. Women in Educational Technology: Content Analysis of AACE Journals 2004-2007

    ERIC Educational Resources Information Center

    Kennedy, Kathryn; Liu, Feng; Dawson, Kara; Cavanaugh, Cathy

    2009-01-01

    Professional qualifications for men and women are equivalent across disciplines, however, women tend to be underrepresented in technology-related fields. The purpose of this study is to analyze the content of seven journals published by the Association for the Advancement of Computing in Education (AACE) to explore women's publications in…

  12. Saudi Special Education Student Teachers' Knowledge of Augmentative and Alternative Communication (AAC)

    ERIC Educational Resources Information Center

    Subihi, Ahmad Saeed

    2013-01-01

    Speech-language pathologists (SLPs), special education teachers (SETs), and occupational therapists (OTs) are all expected to encounter individuals with complex communication needs, who need for Augmentative and alternative communication (AAC) (Costigan & Light, 2010). This study aimed to reveal special education student teachers'…

  13. Effects of Communication Partner Instruction on the Communication of Individuals using AAC: A Meta-Analysis.

    PubMed

    Kent-Walsh, Jennifer; Murza, Kimberly A; Malani, Melissa D; Binger, Cathy

    2015-01-01

    The purpose of this study was to conduct a systematic review and meta-analysis of the augmentative and alternative communication (AAC) partner instruction intervention literature to determine (a) the overall effects of partner interventions on the communication of individuals using AAC, and (b) any possible moderating variables relating to participant, intervention, or outcome characteristics. Seventeen single-case experimental design studies (53 participants) met the inclusion criteria and were advanced to the full coding and analysis phase of the investigation. Descriptive analyses and effect size estimations using the Improvement Rate Difference (IRD) metric were conducted. Overall, communication partner interventions were found to be highly effective across a range of participants using AAC, intervention approaches, and outcome measure characteristics, with more evidence available for participants less than 12 years of age, most of whom had a diagnosis of autism spectrum disorder or intellectual/developmental disability. Aided AAC modeling, expectant delay, and open-ended question asking were the most frequently targeted communication partner interaction skills. Providing a descriptive overview, instructor modeling, guided practice, and role plays were the most frequently incorporated communication partner intervention activities within the included studies. PMID:26059542

  14. Mechanistic and Structural Analysis of Aminoglycoside N-Acetyltransferase AAC(6′)-Ib and Its Bifunctional, Fluoroquinolone-Active AAC(6′)-Ib-cr Variant†,‡

    PubMed Central

    Vetting, Matthew W.; Park, Chi Hye; Hegde, Subray S.; Jacoby, George A.; Hooper, David C.; Blanchard, John S.

    2010-01-01

    Enzymatic modification of aminoglycoside antibiotics mediated by regioselective aminoglycoside N-acetyltransferases is the predominant cause of bacterial resistance to aminoglycosides. A recently discovered bifunctional aminoglycoside acetyltransferase (AAC(6′)-Ib variant, AAC(6′)-Ib-cr) has been shown to catalyze the acetylation of fluoroquinolones as well as aminoglycosides. We have expressed and purified AAC(6′)-Ib-wt and its bifunctional variant AAC(6′)-Ib-cr in Escherichia coli and characterized their kinetic and chemical mechanism. Initial velocity and dead-end inhibition studies support an ordered sequential mechanism for the enzyme(s). The three-dimensional structure of AAC(6′)-Ib-wt was determined in various complexes with donor and acceptor ligands to resolutions greater than 2.2 Å. Observation of the direct, and optimally positioned, interaction between the 6′-NH2 and Asp115 suggests that Asp115 acts as a general base to accept a proton in the reaction. The structure of AAC(6′)-Ib-wt permits the construction of a molecular model of the interactions of fluoroquinolones with the AAC(6′)-Ib-cr variant. The model suggests that a major contribution to the fluoroquinolone acetylation activity comes from the Asp179Tyr mutation, where Tyr179 makes π-stacking interactions with the quinolone ring facilitating quinolone binding. The model also suggests that fluoroquinolones and aminoglycosides have different binding modes. On the basis of kinetic properties, the pH dependence of the kinetic parameters, and structural information, we propose an acid/base-assisted reaction catalyzed by AAC(6′)-Ib-wt and the AAC(6′)-Ib-cr variant involving a ternary complex. PMID:18710261

  15. Effect of aeration rate on composting of penicillin mycelial dreg.

    PubMed

    Chen, Zhiqiang; Zhang, Shihua; Wen, Qinxue; Zheng, Jun

    2015-11-01

    Pilot scale experiments with forced aeration were conducted to estimate effects of aeration rates on the performance of composting penicillin mycelial dreg using sewage sludge as inoculation. Three aeration rates of 0.15, 0.50 and 0.90L/(min·kg) organic matter (OM) were examined. The principal physicochemical parameters were monitored during the 32day composting period. Results showed that the higher aeration rate of 0.90L/(min·kg) did not corresponded to a longer thermophilic duration and higher rates of OM degradation; but the lower aeration rate of 0.15L/(min·kg) did induce an accumulation of NH4(+)-N contents due to the inhibition of nitrification. On the other hand, aeration rate has little effect on degradation of penicillin. The results show that the longest phase of thermophilic temperatures≥55°C, the maximum NO3(-)-N content and seed germination, and the minimum C/N ratio were obtained with 0.50L/(min·kg) OM. Therefore, aeration rates of 0.50L/(min·kg) OM can be recommended for composting penicillin mycelial dreg.

  16. Effect of aeration rate on composting of penicillin mycelial dreg.

    PubMed

    Chen, Zhiqiang; Zhang, Shihua; Wen, Qinxue; Zheng, Jun

    2015-11-01

    Pilot scale experiments with forced aeration were conducted to estimate effects of aeration rates on the performance of composting penicillin mycelial dreg using sewage sludge as inoculation. Three aeration rates of 0.15, 0.50 and 0.90L/(min·kg) organic matter (OM) were examined. The principal physicochemical parameters were monitored during the 32day composting period. Results showed that the higher aeration rate of 0.90L/(min·kg) did not corresponded to a longer thermophilic duration and higher rates of OM degradation; but the lower aeration rate of 0.15L/(min·kg) did induce an accumulation of NH4(+)-N contents due to the inhibition of nitrification. On the other hand, aeration rate has little effect on degradation of penicillin. The results show that the longest phase of thermophilic temperatures≥55°C, the maximum NO3(-)-N content and seed germination, and the minimum C/N ratio were obtained with 0.50L/(min·kg) OM. Therefore, aeration rates of 0.50L/(min·kg) OM can be recommended for composting penicillin mycelial dreg. PMID:26574101

  17. The influence of information and role-playing experiences on children's attitudes toward peers who use AAC.

    PubMed

    Beck, Ann R; Fritz-Verticchio, Heidi

    2003-02-01

    A school-based intervention designed to increase the positive nature of children's attitudes toward peers who use AAC is described. Small groups of children were given only information about AAC or they were given information about AAC and the opportunity to role-play being nonspeaking. Results indicated a greater positive effect of the information plus role-play experience compared to the effects of being given information alone for older children and boys. Clinical implications and suggestions for future research are discussed.

  18. INVESTIGATIONS INTO BIOFOULING PHENOMENA IN FINE PORE AERATION DEVICES

    EPA Science Inventory

    Microbiologically-based procedures were used to describe biofouling phenomena on fine pore aeration devices and to determine whether biofilm characteristics could be related to diffuser process performance parameters. Fine pore diffusers were obtained from five municipal wastewa...

  19. Increased prevalence of aminoglycoside resistance in clinical isolates of Escherichia coli and Klebsiella spp. in Norway is associated with the acquisition of AAC(3)-II and AAC(6')-Ib.

    PubMed

    Haldorsen, Bjørg C; Simonsen, Gunnar Skov; Sundsfjord, Arnfinn; Samuelsen, Orjan

    2014-01-01

    In this study, we show that the increasing prevalence of aminoglycoside resistance observed in Norway among clinical Escherichia coli and Klebsiella spp. isolates is mainly due to the presence of the aminoglycoside-modifying enzymes AAC(3)-II and AAC(6')-Ib. A frequent co-association of aminoglycoside resistance with Cefotaximase-München group 1 extended-spectrum β-lactamases was also observed.

  20. Spanish language generation engine to enhance the syntactic quality of AAC systems

    NASA Astrophysics Data System (ADS)

    Narváez A., Cristian; Sastoque H., Sebastián.; Iregui G., Marcela

    2015-12-01

    People with Complex Communication Needs (CCN) face difficulties to communicate their ideas, feelings and needs. Augmentative and Alternative Communication (AAC) approaches aim to provide support to enhance socialization of these individuals. However, there are many limitations in current applications related with systems operation, target scenarios and language consistency. This work presents an AAC approach to enhance produced messages by applying elements of Natural Language Generation. Specifically, a Spanish language engine, composed of a grammar ontology and a set of linguistic rules, is proposed to improve the naturalness in the communication process, when persons with CCN tell stories about their daily activities to non-disabled receivers. The assessment of the proposed method confirms the validity of the model to improve messages quality.

  1. 17 Ways to Say Yes: Toward Nuanced Tone of Voice in AAC and Speech Technology.

    PubMed

    Pullin, Graham; Hennig, Shannon

    2015-06-01

    People with complex communication needs who use speech-generating devices have very little expressive control over their tone of voice. Despite its importance in human interaction, the issue of tone of voice remains all but absent from AAC research and development however. In this paper, we describe three interdisciplinary projects, past, present and future: The critical design collection Six Speaking Chairs has provoked deeper discussion and inspired a social model of tone of voice; the speculative concept Speech Hedge illustrates challenges and opportunities in designing more expressive user interfaces; the pilot project Tonetable could enable participatory research and seed a research network around tone of voice. We speculate that more radical interactions might expand frontiers of AAC and disrupt speech technology as a whole.

  2. 17 Ways to Say Yes: Toward Nuanced Tone of Voice in AAC and Speech Technology

    PubMed Central

    Pullin, Graham; Hennig, Shannon

    2015-01-01

    Abstract People with complex communication needs who use speech-generating devices have very little expressive control over their tone of voice. Despite its importance in human interaction, the issue of tone of voice remains all but absent from AAC research and development however. In this paper, we describe three interdisciplinary projects, past, present and future: The critical design collection Six Speaking Chairs has provoked deeper discussion and inspired a social model of tone of voice; the speculative concept Speech Hedge illustrates challenges and opportunities in designing more expressive user interfaces; the pilot project Tonetable could enable participatory research and seed a research network around tone of voice. We speculate that more radical interactions might expand frontiers of AAC and disrupt speech technology as a whole. PMID:25965913

  3. 17 Ways to Say Yes: Toward Nuanced Tone of Voice in AAC and Speech Technology.

    PubMed

    Pullin, Graham; Hennig, Shannon

    2015-06-01

    People with complex communication needs who use speech-generating devices have very little expressive control over their tone of voice. Despite its importance in human interaction, the issue of tone of voice remains all but absent from AAC research and development however. In this paper, we describe three interdisciplinary projects, past, present and future: The critical design collection Six Speaking Chairs has provoked deeper discussion and inspired a social model of tone of voice; the speculative concept Speech Hedge illustrates challenges and opportunities in designing more expressive user interfaces; the pilot project Tonetable could enable participatory research and seed a research network around tone of voice. We speculate that more radical interactions might expand frontiers of AAC and disrupt speech technology as a whole. PMID:25965913

  4. Reading instruction for children who use AAC: considerations in the pursuit of generalizable results.

    PubMed

    Michael Barker, R; Saunders, Kathryn J; Brady, Nancy C

    2012-09-01

    Our purpose was to review evidence-based literacy instruction for children with severe speech impairment (SSI) who communicate with AAC. This review focuses on three issues important to researchers in this area: participant heterogeneity, assessment and instruction tasks, and research design. We found eight articles that reported attempts to teach phonological awareness and individual-word reading to a total of 26 children with SSI who used AAC. We evaluated these studies based on reporting of participant characteristics, assessment and instruction modifications, and the strength of research designs. We conclude by highlighting the need for standard assessments that can be used across studies, discussing strategies for facilitating meta-analyses, and suggesting the creation of an online database for researchers to share results on literacy instruction for this population. PMID:22946991

  5. [Improvement of River Water Quality by Aeration: WASP Model Study].

    PubMed

    Zhu, Wen-bo; Wang, Hong-xiu; Liu, Cui; Zhang, Jian; Liang, Shuang

    2015-04-01

    Aeration is one of the main technical methods to remediate polluted rivers, and mathematical models are the main ways to predict and assess the environmental pollution. WASP model was used to study the effect of aeration on improving the water quality of a small river over a time span. The preliminary results showed that the simulation values were consistent with practical monitoring data, which could be useful for the management and control of polluted water. Furthermore, simulations under different aeration conditions suggested that aeration technology could significantly lower the levels of chemical oxygen demand (COD) and ammonia-nitrogen (NH4(+)-N) of river water, thus improving the water quality. With the improvement of dissolved oxygen (DO), the water quality could be further improved. However, the increase in the removal rate of pollutants would slow down. Also, there were remarkable differences among various months throughout the whole year, and aeration from May to September had better results. Considering economic costs and environmental benefits, river aeration with a 4 mg x L(1) DO standard in summer was determined as the best condition.

  6. Generating CO(2)-credits through landfill in situ aeration.

    PubMed

    Ritzkowski, M; Stegmann, R

    2010-04-01

    Landfills are some of the major anthropogenic sources of methane emissions worldwide. The installation and operation of gas extraction systems for many landfills in Europe and the US, often including technical installations for energy recovery, significantly reduced these emissions during the last decades. Residual landfill gas, however, is still continuously produced after the energy recovery became economically unattractive, thus resulting in ongoing methane emissions for many years. By landfill in situ aeration these methane emissions can be widely avoided both, during the aeration process as well as in the subsequent aftercare period. Based on model calculations and online monitoring data the amount of avoided CO(2-eq). can be determined. For an in situ aerated landfill in northern Germany, acting as a case study, 83-95% (depending on the kind and quality of top cover) of the greenhouse gas emission potential could be reduced under strictly controlled conditions. Recently the United Nations Framework Convention on Climate Change (UNFCCC) has approved a new methodology on the "Avoidance of landfill gas emissions by in situ aeration of landfills" (UNFCCC, 2009). Based on this methodology landfill aeration projects might be considered for generation of Certified Emission Reductions (CERs) in the course of CDM projects. This paper contributes towards an evaluation of the potential of landfill aeration for methane emissions reduction.

  7. Enhancement of Nitrogen Removal in an Intermittent Aeration Membrane Bioreactor

    NASA Astrophysics Data System (ADS)

    He, Xiaojuan; Wisniewski, Christelle; Li, Xudong; Zhou, Qi

    2010-11-01

    An intermittent aerated membrane bioreactor was applied in laboratory scale to treat synthetic household wastewater. The system organic load and nitrogen load were 0.34 kgCODṡm-3ṡd-1 and 0.06 kgTNṡm-3ṡd-1, respectively. The hydraulic residence time was equal to 12 h and very long sludge residence times were imposed. Intermittent aeration, with anoxic-aerobic cycle of 30/60 minutes, was employed in the system. The results showed that 100% SS and >90% COD could be removed. The average removal efficiency of NH4-N and TN was 99.7% and 80%, respectively. A linear relationship between the fouling rate and the MLSS, MLVSS concentration was founded. The denitrification seemed to be the rate-limiting step for nitrogen removal. To enhance denitrification, the following strategies could be considered: 1) to select suitable aeration/non-aeration cycle, 2) to control the aeration intensity, 3) to feed the system at the beginning of non-aeration period, 4) to maintain high MLSS concentration.

  8. Refractory concretes

    DOEpatents

    Holcombe, Jr., Cressie E.

    1979-01-01

    Novel concrete compositions comprise particles of aggregate material embedded in a cement matrix, said cement matrix produced by contacting an oxide selected from the group of Y.sub.2 O.sub.3, La.sub.2 O.sub.3, Nd.sub.2 O.sub.3, Sm.sub.2 O.sub.3, Eu.sub.2 O.sub.3 and Gd.sub.2 O.sub.3 with an aqueous solution of a salt selected from the group of NH.sub.4 NO.sub.3, NH.sub.4 Cl, YCl.sub.3 and Mg(NO.sub.3).sub.2 to form a fluid mixture; and allowing the fluid mixture to harden.

  9. Injectable hydrogel as stem cell scaffolds from the thermosensitive terpolymer of NIPAAm/AAc/HEMAPCL

    PubMed Central

    Lian, Sheng; Xiao, Yan; Bian, Qingqing; Xia, Yu; Guo, Changfa; Wang, Shenguo; Lang, Meidong

    2012-01-01

    A series of biodegradable thermosensitive copolymers was synthesized by free radical polymerization with N-isopropylacrylamide (NIPAAm), acrylic acid (AAc) and macromer 2-hydroxylethyl methacrylate-poly(ɛ-caprolactone) (HEMAPCL). The structure and composition of the obtained terpolymers were confirmed by proton nuclear magnetic resonance spectroscopy, while their molecular weight was measured using gel permeation chromatography. The copolymers were dissolved in phosphate-buffered saline (PBS) solution (pH = 7.4) with different concentrations to prepare hydrogels. The lower critical solution temperature (LCST), cloud point, and rheological property of the hydrogels were determined by differential scanning calorimetry, ultraviolet-visible spectrometry, and rotational rheometry, respectively. It was found that LCST of the hydrogel increased significantly with the increasing NIPAAm content, and hydrogel with higher AAc/HEMAPCL ratio exhibited better storage modulus, water content, and injectability. The hydrogels were formed by maintaining the copolymer solution at 37°C. The degradation experiment on the formed hydrogels was conducted in PBS solution for 2 weeks and demonstrated a less than 20% weight loss. Scanning electron microscopy was also used to study the morphology of the hydrogel. The copolymer with NIPAAm/AAc/HEMAPCL ratio of 88:9.6:2.4 was bioconjugated with type I collagen for the purpose of biocompatibility enhancement. In-vitro cytotoxicity of the hydrogels both with and without collagen was also addressed. PMID:23028218

  10. Detection of aac(6’)-Ib-cr in Avian Pathogenic Escherichia coli Isolates in Japan

    PubMed Central

    KAWANISHI, Michiko; OZAWA, Manao; HIKI, Mototaka; ABO, Hitoshi; KOJIMA, Akemi; ASAI, Tetsuo

    2013-01-01

    ABSTRACT We investigated the prevalence of plasmid-mediated quinolone resistance (PMQR) genes in avian pathogenic Escherichia coli (APEC) strains in Japan. A total of 117 APEC strains collected between 2004 and 2007 were examined for PMQR genes (qnrA, qnrB, qnrC, qnrD, qnrS, aac(6’)-Ib-cr, qepA and oqxAB) by polymerase chain reaction. None of the APEC strains carried qnrA, qnrB, qnrC, qnrD, qnrS, qepA or oqxAB, but one of the isolates was identified as an AAC (6’)-Ib-cr producer. Phylogenetic grouping, multi-locus sequence typing and serotyping showed that this isolate belonged to phylogenetic group A, sequence type 167 and untypable serogroup. To our knowledge, this is the first report of the aac (6’)-Ib-cr gene in bacteria from food-producing animals in Japan. PMID:23856759

  11. Family influences and academic success: the perceptions of individuals using AAC.

    PubMed

    Rackensperger, Tracy

    2012-06-01

    Positive family influences have a significant impact on addressing school barriers to academic success for students from socially disadvantaged backgrounds. Due to inequities and attitudes toward people with complex communication needs, positive family influences may be critical in the academic success of students using AAC. This study asked the following question of eight United States high school graduates who have used augmentative and alternative communication (AAC): How do family influences positively affect the ability of students who use AAC to succeed in the secondary academic environment? Five themes emerged from the qualitative analysis of participants' narratives: (a) the impact of the family in seeking appropriate education, (b) homework as a challenge that was made easier through the involvement of the family, (c) the role of the family in communicating the importance of education, (d) mothers as driving forces of support, and (e) family encouragement for self-determination. This research allows families and schools to recognize the needs of students and to take action to meet them. It identifies the needs of families and schools in establishing relationships with each other, in terms of supporting requirements for accommodation, learning, motivation, and self-determination of students with complex commmunication needs. PMID:22670728

  12. The Effect of Voice Output on the AAC-Supported Conversations of Persons with Alzheimer’s Disease

    PubMed Central

    Fried-Oken, Melanie; Rowland, Charity; Baker, Glory; Dixon, Mayling; Mills, Carolyn; Schultz, Darlene; Oken, Barry

    2011-01-01

    The purpose of this study was to determine whether the presence or absence of digitized 1–2 word voice output on a direct selection, customized augmentative and alternative communication (AAC) device would affect the impoverished conversations of persons with dementia. Thirty adults with moderate Alzheimer’s disease participated in two personally relevant conversations with an AAC device. For 12 of the participants the AAC device included voice output. The AAC device was the Flexiboard™ containing 16 messages needed to discuss a favorite autobiographical topic chosen by the participant and his/her family caregivers. Ten-minute conversations were videotaped in participants’ residences and analyzed for four conversational measures related to the participants’ communicative behavior. Results show that AAC devices with digitized voice output depress conversational performance and distract participants with moderate Alzheimer’s disease as compared to similar devices without voice output. There were significantly more 1-word utterances and fewer total utterances when AAC devices included voice output, and the rate of topic elaborations/initiations was significantly lower when voice output was present. Discussion about the novelty of voice output for this population of elders and the need to train elders to use this technology is provided. PMID:21785666

  13. Teaching Latino parents to support the multi-symbol message productions of their children who require AAC.

    PubMed

    Binger, Cathy; Kent-Walsh, Jennifer; Berens, Jacqueline; Del Campo, Stephanie; Rivera, Donna

    2008-12-01

    Many children who require augmentative and alternative communication (AAC) have difficulties shifting from the single- to multi-symbol stage of language development. Ensuring that children who use AAC receive evidence-based interventions to address this problem is critical. Furthermore, there has been little AAC treatment efficacy research to date that addresses the needs of multicultural populations, particularly those of Latino children who use AAC and their families. To address these issues, the current investigation used a mixed methodology, which included a focus group to determine if any changes needed to be made to an existing instructional program; and a single subject, multiple probe, across participants design to evaluate the effects of a caregiver instructional program on the multi-symbol utterance productions of Latino children who used AAC. Specifically, a cognitive strategy instructional approach that has been used to teach turn-taking skills to both Caucasian and African American children who use AAC was modified and used to teach caregivers how to support the production of their children's multi-symbol messages. In order to foster emergent literacy skills, caregivers implemented the strategy during book reading activities. Focus group results revealed that changes to the instructional program may be required for some Latino families. With regard to the instructional program, all caregivers successfully learned to use the instructional strategy, and all children increased their use of multi-symbol messages. Research and clinical implications of the findings are discussed.

  14. Teaching Latino parents to support the multi-symbol message productions of their children who require AAC.

    PubMed

    Binger, Cathy; Kent-Walsh, Jennifer; Berens, Jacqueline; Del Campo, Stephanie; Rivera, Donna

    2008-12-01

    Many children who require augmentative and alternative communication (AAC) have difficulties shifting from the single- to multi-symbol stage of language development. Ensuring that children who use AAC receive evidence-based interventions to address this problem is critical. Furthermore, there has been little AAC treatment efficacy research to date that addresses the needs of multicultural populations, particularly those of Latino children who use AAC and their families. To address these issues, the current investigation used a mixed methodology, which included a focus group to determine if any changes needed to be made to an existing instructional program; and a single subject, multiple probe, across participants design to evaluate the effects of a caregiver instructional program on the multi-symbol utterance productions of Latino children who used AAC. Specifically, a cognitive strategy instructional approach that has been used to teach turn-taking skills to both Caucasian and African American children who use AAC was modified and used to teach caregivers how to support the production of their children's multi-symbol messages. In order to foster emergent literacy skills, caregivers implemented the strategy during book reading activities. Focus group results revealed that changes to the instructional program may be required for some Latino families. With regard to the instructional program, all caregivers successfully learned to use the instructional strategy, and all children increased their use of multi-symbol messages. Research and clinical implications of the findings are discussed. PMID:18608143

  15. [Effect of Low-concentration Ciprofloxacin on the Nitrification and Nitrifying Microorganisms of Biofilms in Biological Aerated Filter].

    PubMed

    He, Shi; Gu, Chao-chao; Wei, Xin; Huang, Sheng-lin; Liu, Zhen-hong; Xue, Gang; Gao, Pin

    2016-04-15

    Effect of low-concentration ciprofloxacin (CIP) on nitrification and nitrifying microorganisms of biofilms was studied in biological aerated filters (BAF). Quantitative PCR (qPCR) was used to determine the abundance variance of four ciprofloxacin resistance genes (CIP-ARGs) during nitrification in biofilms. The correlations between the abundances of CIP-ARGs and nitrifying microorganisms were also discussed. The results showed that CIP had little influence on the ammonium oxidation process of biofilm microorganisms, whereas inhibition of the nitrite oxidation process was found. The quantitative results of ammonium-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) including Nitrobacter and Nitrospira indicated that the inhibition on the transformation of nitrite was resulted from the inhibition on Nitrobacter and Nitrospira. In addition, little influence of CIP on the relative abundance of aac and qepA in biofilms was found, but the influence on parC and oqxB was great. The abundance of Nitrotacter exhibited significant positive correlation with the abundance of parC. Similar significant correlation was also found between the abundances of Nitrospira and oqxB. It could be speculated that the genetic elements of different nitrifying microorganisms in biofilms possibly carried CIP-ARGs. PMID:27548973

  16. A new step aeration approach towards the improvement of nitrogen removal in a full scale Carrousel oxidation ditch.

    PubMed

    Jin, Pengkang; Wang, Xianbao; Wang, Xiaochang; Ngo, Huu Hao; Jin, Xin

    2015-12-01

    Two aeration modes, step aeration and point aeration, were used in a full-scale Carrousel oxidation ditch with microporous aeration. The nitrogen removal performance and mechanism were analyzed. With the same total aeration input, both aeration modes demonstrated good nitrification outcomes with the average efficiency in removing NH4(+)-N of more than 98%. However, the average removal efficiencies for total nitrogen were 89.3% and 77.6% under step aeration and point aeration, respectively. The results indicated that an extended aerobic zone followed the aeration zones could affect the proportion of anoxic and oxic zones. The step aeration with larger anoxic zones indicated better TN removal efficiency. More importantly, step aeration provided the suitable environment for both nitrifiers and denitrifiers. The diversity and relative abundance of denitrifying bacteria under the step aeration (1.55%) was higher than that under the point aeration (1.12%), which resulted in an overall higher TN removal efficiency.

  17. iRSpot-TNCPseAAC: identify recombination spots with trinucleotide composition and pseudo amino acid components.

    PubMed

    Qiu, Wang-Ren; Xiao, Xuan; Chou, Kuo-Chen

    2014-01-01

    Meiosis and recombination are the two opposite aspects that coexist in a DNA system. As a driving force for evolution by generating natural genetic variations, meiotic recombination plays a very important role in the formation of eggs and sperm. Interestingly, the recombination does not occur randomly across a genome, but with higher probability in some genomic regions called "hotspots", while with lower probability in so-called "coldspots". With the ever-increasing amount of genome sequence data in the postgenomic era, computational methods for effectively identifying the hotspots and coldspots have become urgent as they can timely provide us with useful insights into the mechanism of meiotic recombination and the process of genome evolution as well. To meet the need, we developed a new predictor called "iRSpot-TNCPseAAC", in which a DNA sample was formulated by combining its trinucleotide composition (TNC) and the pseudo amino acid components (PseAAC) of the protein translated from the DNA sample according to its genetic codes. The former was used to incorporate its local or short-rage sequence order information; while the latter, its global and long-range one. Compared with the best existing predictor in this area, iRSpot-TNCPseAAC achieved higher rates in accuracy, Mathew's correlation coefficient, and sensitivity, indicating that the new predictor may become a useful tool for identifying the recombination hotspots and coldspots, or, at least, become a complementary tool to the existing methods. It has not escaped our notice that the aforementioned novel approach to incorporate the DNA sequence order information into a discrete model may also be used for many other genome analysis problems. The web-server for iRSpot-TNCPseAAC is available at http://www.jci-bioinfo.cn/iRSpot-TNCPseAAC. Furthermore, for the convenience of the vast majority of experimental scientists, a step-by-step guide is provided on how to use the current web server to obtain their desired

  18. Characterization of Odorant Compounds from Mechanical Aerated Pile Composting and Static Aerated Pile Composting.

    PubMed

    Kumari, Priyanka; Lee, Joonhee; Choi, Hong-Lim

    2016-04-01

    We studied airborne contaminants (airborne particulates and odorous compounds) emitted from compost facilities in South Korea. There are primarily two different types of composting systems operating in Korean farms, namely mechanical aerated pile composting (MAPC) and aerated static pile composting (SAPC). In this study, we analyzed various particulate matters (PM10, PM7, PM2.5, PM1, and total suspended particles), volatile organic compounds and ammonia, and correlated these airborne contaminants with microclimatic parameters, i.e., temperature and relative humidity. Most of the analyzed airborne particulates (PM7, PM2.5, and PM1) were detected in high concentration at SAPC facilities compered to MAPC; however these differences were statistically non-significant. Similarly, most of the odorants did not vary significantly between MAPC and SAPC facilities, except for dimethyl sulfide (DMS) and skatole. DMS concentrations were significantly higher in MAPC facilities, whereas skatole concentrations were significantly higher in SAPC facilities. The microclimate variables also did not vary significantly between MAPC and SAPC facilities, and did not correlate significantly with most of the airborne particles and odorous compounds, suggesting that microclimate variables did not influence their emission from compost facilities. These findings provide insight into the airborne contaminants that are emitted from compost facilities and the two different types of composting agitation systems. PMID:26949962

  19. Characterization of Odorant Compounds from Mechanical Aerated Pile Composting and Static Aerated Pile Composting

    PubMed Central

    Kumari, Priyanka; Lee, Joonhee; Choi, Hong-Lim

    2016-01-01

    We studied airborne contaminants (airborne particulates and odorous compounds) emitted from compost facilities in South Korea. There are primarily two different types of composting systems operating in Korean farms, namely mechanical aerated pile composting (MAPC) and aerated static pile composting (SAPC). In this study, we analyzed various particulate matters (PM10, PM7, PM2.5, PM1, and total suspended particles), volatile organic compounds and ammonia, and correlated these airborne contaminants with microclimatic parameters, i.e., temperature and relative humidity. Most of the analyzed airborne particulates (PM7, PM2.5, and PM1) were detected in high concentration at SAPC facilities compered to MAPC; however these differences were statistically non-significant. Similarly, most of the odorants did not vary significantly between MAPC and SAPC facilities, except for dimethyl sulfide (DMS) and skatole. DMS concentrations were significantly higher in MAPC facilities, whereas skatole concentrations were significantly higher in SAPC facilities. The microclimate variables also did not vary significantly between MAPC and SAPC facilities, and did not correlate significantly with most of the airborne particles and odorous compounds, suggesting that microclimate variables did not influence their emission from compost facilities. These findings provide insight into the airborne contaminants that are emitted from compost facilities and the two different types of composting agitation systems. PMID:26949962

  20. [Research of controlling condition for aeration stabilization pond dealing with sanitary waste of countryside].

    PubMed

    Li, Huai-Zheng; Yao, Shu-Jun; Xu, Zu-Xin; Chen, Wei-Bing

    2012-10-01

    According to research of some problems, such as the hydraulic detention time that aeration stabilization pond deals with sanitary waste of countryside, dissolved oxygen in pond during the process of aeration, the concentration distribution of sludge and different aeration periods affecting on the treatment efficiency, we can acquire good treatment efficiency and energy consumption of economy. The results indicate that under the aeration stabilization pond of this experiment, 4 d is the best hydraulic detention time with this aeration stabilization pond. Time of the discontinuous running aeration should be greater than 15 min. The concentration distribution of sludge can reach equilibrium at each point of aeration stabilization pond between 2 min and 10 min. The best aeration period of dislodging the pollutant is 0.5 h aeration/1.0 h cut-off.

  1. Seasonal variations and aeration effects on water quality improvements and physiological responses of Nymphaea tetragona Georgi.

    PubMed

    Lu, Xiao-Ming; Lu, Peng-Zhen; Huang, Min-Sheng; Dai, Ling-Peng

    2013-01-01

    Seasonal variations and aeration effects on water quality improvements and the physiological responses of Nymphaea tetragona Georgi were investigated with mesocosm experiments. Plants were hydroponically cultivated in six purifying tanks (aerated, non-aerated) and the characteristics of the plants were measured. Water quality improvements in purifying tanks were evaluated by comparing to the control tanks. The results showed that continuous aeration affected the plant morphology and physiology. The lengths of the roots, petioles and leaf limbs in aeration conditions were shorter than in non-aeration conditions. Chlorophyll and soluble protein contents of the leaf limbs in aerated tanks decreased, while peroxidase and catalase activities of roots tissues increased. In spring and summer, effects of aeration on the plants were less than in autumn. Total nitrogen (TN) and ammonia nitrogen (NH4(+)-N) in aerated tanks were lower than in non-aerated tanks, while total phosphorus (TP) and dissolved phosphorus (DP) increased in spring and summer. In autumn, effects of aeration on the plants became more significant. TN, NH4(+)-N, TP and DP became higher in aerated tanks than in non-aerated tanks in autumn. This work provided evidences for regulating aeration techniques based on seasonal variations of the plant physiology in restoring polluted stagnant water.

  2. Seasonal variations and aeration effects on water quality improvements and physiological responses of Nymphaea tetragona Georgi.

    PubMed

    Lu, Xiao-Ming; Lu, Peng-Zhen; Huang, Min-Sheng; Dai, Ling-Peng

    2013-01-01

    Seasonal variations and aeration effects on water quality improvements and the physiological responses of Nymphaea tetragona Georgi were investigated with mesocosm experiments. Plants were hydroponically cultivated in six purifying tanks (aerated, non-aerated) and the characteristics of the plants were measured. Water quality improvements in purifying tanks were evaluated by comparing to the control tanks. The results showed that continuous aeration affected the plant morphology and physiology. The lengths of the roots, petioles and leaf limbs in aeration conditions were shorter than in non-aeration conditions. Chlorophyll and soluble protein contents of the leaf limbs in aerated tanks decreased, while peroxidase and catalase activities of roots tissues increased. In spring and summer, effects of aeration on the plants were less than in autumn. Total nitrogen (TN) and ammonia nitrogen (NH4(+)-N) in aerated tanks were lower than in non-aerated tanks, while total phosphorus (TP) and dissolved phosphorus (DP) increased in spring and summer. In autumn, effects of aeration on the plants became more significant. TN, NH4(+)-N, TP and DP became higher in aerated tanks than in non-aerated tanks in autumn. This work provided evidences for regulating aeration techniques based on seasonal variations of the plant physiology in restoring polluted stagnant water. PMID:23819294

  3. Numerical simulation of landfill aeration using computational fluid dynamics.

    PubMed

    Fytanidis, Dimitrios K; Voudrias, Evangelos A

    2014-04-01

    The present study is an application of Computational Fluid Dynamics (CFD) to the numerical simulation of landfill aeration systems. Specifically, the CFD algorithms provided by the commercial solver ANSYS Fluent 14.0, combined with an in-house source code developed to modify the main solver, were used. The unsaturated multiphase flow of air and liquid phases and the biochemical processes for aerobic biodegradation of the organic fraction of municipal solid waste were simulated taking into consideration their temporal and spatial evolution, as well as complex effects, such as oxygen mass transfer across phases, unsaturated flow effects (capillary suction and unsaturated hydraulic conductivity), temperature variations due to biochemical processes and environmental correction factors for the applied kinetics (Monod and 1st order kinetics). The developed model results were compared with literature experimental data. Also, pilot scale simulations and sensitivity analysis were implemented. Moreover, simulation results of a hypothetical single aeration well were shown, while its zone of influence was estimated using both the pressure and oxygen distribution. Finally, a case study was simulated for a hypothetical landfill aeration system. Both a static (steadily positive or negative relative pressure with time) and a hybrid (following a square wave pattern of positive and negative values of relative pressure with time) scenarios for the aeration wells were examined. The results showed that the present model is capable of simulating landfill aeration and the obtained results were in good agreement with corresponding previous experimental and numerical investigations.

  4. Cardiopulmonary changes with aeration of the newborn lung.

    PubMed

    Hooper, Stuart Brian; Polglase, Graeme Roger; Roehr, Charles Christoph

    2015-06-01

    The newborn's transition from fetal to neonatal life includes aeration of the lungs, establishment of pulmonary gas exchange and changing the fetal circulation into the adult phenotype. This review summarizes the latest research findings, which show that lung aeration, airway liquid clearance and cardiovascular changes are directly interconnected at birth. The mechanisms of airway liquid clearance at birth are reviewed and the particular importance of the transpulmonary pressure gradient during lung aeration is discussed. Further, we summarize research findings which prove that lung aeration triggers the increase in pulmonary blood flow (PBF) at birth, and how the increase in PBF secures the preload for left ventricular output. Consequently, we review animal experiments which suggest that delaying umbilical cord clamping until breathing commences facilitates hemodynamic stability during transition. These data are reviewed with respect to the clinical applicability: As lung aeration is the key to successful transition to newborn life, providing adequate respiratory support at birth must be the primary objective of neonatal staff attending to the newborn infant. Clinical studies are needed to demonstrate whether the obvious benefits of delaying cord clamping until breathing commences hold true in human babies.

  5. Pure and aerated water entry of a flat plate

    NASA Astrophysics Data System (ADS)

    Ma, Z. H.; Causon, D. M.; Qian, L.; Mingham, C. G.; Mai, T.; Greaves, D.; Raby, A.

    2016-01-01

    This paper presents an experimental and numerical investigation of the entry of a rigid square flat plate into pure and aerated water. Attention is focused on the measurement and calculation of the slamming loads on the plate. The experimental study was carried out in the ocean basin at Plymouth University's COAST laboratory. The present numerical approach extends a two-dimensional hydro-code to compute three-dimensional hydrodynamic impact problems. The impact loads on the structure computed by the numerical model compare well with laboratory measurements. It is revealed that the impact loading consists of distinctive features including (1) shock loading with a high pressure peak, (2) fluid expansion loading associated with very low sub-atmospheric pressure close to the saturated vapour pressure, and (3) less severe secondary reloading with super-atmospheric pressure. It is also disclosed that aeration introduced into water can effectively reduce local pressures and total forces on the flat plate. The peak impact loading on the plate can be reduced by half or even more with 1.6% aeration in water. At the same time, the lifespan of shock loading is prolonged by aeration, and the variation of impulse is less sensitive to the change of aeration than the peak loading.

  6. Changes in ciprofloxacin resistance levels in Enterobacter aerogenes isolates associated with variable expression of the aac(6')-Ib-cr gene.

    PubMed

    Ruiz, Elena; Ocampo-Sosa, Alain A; Alcoba-Flórez, Julia; Román, Elena; Arlet, Guillaume; Torres, Carmen; Martínez-Martínez, Luis

    2012-02-01

    Two closely related Enterobacter aerogenes isolates presented a new identical aac(6')-Ib-cr genetic environment, including IS26. One isolate showed lower MICs of ciprofloxacin, norfloxacin, tobramycin, and amikacin and decreased expression of aac(6')-Ib-cr, which might be related to a 12-bp deletion causing a displacement of the -10 box upstream of the aac(6')-Ib-cr gene.

  7. Control of a mechanical aeration process via topological sensitivity analysis

    NASA Astrophysics Data System (ADS)

    Abdelwahed, M.; Hassine, M.; Masmoudi, M.

    2009-06-01

    The topological sensitivity analysis method gives the variation of a criterion with respect to the creation of a small hole in the domain. In this paper, we use this method to control the mechanical aeration process in eutrophic lakes. A simplified model based on incompressible Navier-Stokes equations is used, only considering the liquid phase, which is the dominant one. The injected air is taken into account through local boundary conditions for the velocity, on the injector holes. A 3D numerical simulation of the aeration effects is proposed using a mixed finite element method. In order to generate the best motion in the fluid for aeration purposes, the optimization of the injector location is considered. The main idea is to carry out topological sensitivity analysis with respect to the insertion of an injector. Finally, a topological optimization algorithm is proposed and some numerical results, showing the efficiency of our approach, are presented.

  8. Aspects concerning the quality of aeration for environmental friendly turbines

    NASA Astrophysics Data System (ADS)

    Bunea, F.; Houde, S.; Ciocan, G. D.; Oprina, G.; Baran, G.; Pincovschi, I.

    2010-08-01

    The hydro renewable energy provides a reliable power source; it does not pollute the air or land but affects the aquatic habitat due to low dissolved oxygen (DO) level in the water discharged from turbines. Hydro-turbines intake generally withdraws water from the bottom layer of the reservoirs with low DO level. In the different methods used for improving DO downstream the hydropower plants the volume of air is considered to be the main parameter of the injection. The energetic consumption is affected, in terms of loss of turbine efficiency due to air injection. The authors propose a study to show the importance of the quality of air injection, meaning bubble size, pressure loss on the aeration device etc. Different types of fine bubble aeration systems have been tested and compared. The capacity to predict the aeration by numerical simulation is analysed.

  9. The role of PaAAC1 encoding a mitochondrial ADP/ATP carrier in the biosynthesis of extracellular glycolipids, mannosylerythritol lipids, in the basidiomycetous yeast Pseudozyma antarctica.

    PubMed

    Morita, Tomotake; Ito, Emi; Fukuoka, Tokuma; Imura, Tomohiro; Kitamoto, Dai

    2010-07-01

    Pseudozyma antarctica produces large amounts of the glycolipid biosurfactants known as mannosylerythritol lipids (MEL), which show not only excellent surface-active properties but also versatile biochemical actions. A gene homologous with a mitochondrial ADP/ATP carrier was dominantly expressed in P. antarctica under MEL-producing conditions on the basis of previous gene expression analysis. The gene encoding the mitochondrial ADP/ATP carrier of P. antarctica (PaAAC1) contained a putative open reading frame of 954 bp and encodes a polypeptide of 317 amino acids. The deduced translation product shared high identity of 66%, 70%, 69%, 74%, 75% and 52% with the mitochondrial ADP/ATP carrier of Saccharomyces cerevisiae (AAC1), S. cerevisiae (AAC2), S. cerevisiae (AAC3), Kluyveromyces lactis (KlAAC), Neurospora crassa (NcAAC) and human (ANT1), respectively, and conserved the consensus sequences of all ADP/ATP carrier proteins. The gene expression by introducing a plasmid pUXV1-PaAAC1 into the yeast cells increased the MEL production. In addition, the expression of PaAAC1 in which the conserved arginine and leucine required for ATP transport activity were replaced with isoleucine and serine, respectively, failed to increase MEL production. Accordingly, these results suggest that PaAAC1 encoding a mitochondrial ADP/ATP carrier should be involved in MEL biosynthesis in the yeast. PMID:20146402

  10. Aeration for plant root respiration in a tidal marsh

    NASA Astrophysics Data System (ADS)

    Li, Hailong; Li, Ling; Lockington, David

    2005-06-01

    This paper investigates the tidal effects on aeration conditions for plant root respiration in a tidal marsh. We extend the work of Ursino et al. (2004) by using a two-phase model for air and water flows in the marsh. Simulations have been conducted to examine directly the link between the airflow dynamics and the aeration condition in the marsh soil. The results show that the effects of entrapped air on water movement in the vadose zone are significant in certain circumstances. Single-phase models based on Richards' equation, which neglect such effects, may not be adequate for quantifying the aeration condition in tidal marsh. The optimal aeration condition, represented by the maximum of the integral magnitude of tidally advected air mass (TAAM) flux, is found to occur near the tidal creek for the four soil textures simulated. This may explain the observation that some salt marsh plant species grow better near tidal creeks than in the inner marsh areas. Our analyses, based on the two-phase model and predicted TAAM flux magnitude, provide further insight into the "positive feedback" mechanism proposed by Ursino et al. (2004). That is, pioneer plants may grow successfully near the creek where the root aeration condition is optimal. The roots of the pioneer plants can soften and loosen the rhizosphere soil, which increases the evapotranspiration rate, the soil porosity, and absolute permeability and weakens the capillary effects. These, in turn, improve further the root aeration conditions and may lead to colonization by plants less resistant to anaerobic conditions.

  11. Aeration for plant root respiration in a tidal marsh

    NASA Astrophysics Data System (ADS)

    Li, Hailong; Li, Ling; Lockington, David

    2005-06-01

    This paper investigates the tidal effects on aeration conditions for plant root respiration in a tidal marsh. We extend the work of Ursino et al. (2004) by using a two-phase model for air and water flows in the marsh. Simulations have been conducted to examine directly the link between the airflow dynamics and the aeration condition in the marsh soil. The results show that the effects of entrapped air on water movement in the vadose zone are significant in certain circumstances. Single-phase models based on Richards' equation, which neglect such effects, may not be adequate for quantifying the aeration condition in tidal marsh. The optimal aeration condition, represented by the maximum of the integral magnitude of tidally advected air mass (TAAM) flux, is found to occur near the tidal creek for the four soil textures simulated. This may explain the observation that some salt marsh plant species grow better near tidal creeks than in the inner marsh areas. Our analyses, based on the two-phase model and predicted TAAM flux magnitude, provide further insight into the ``positive feedback'' mechanism proposed by Ursino et al. (2004). That is, pioneer plants may grow successfully near the creek where the root aeration condition is optimal. The roots of the pioneer plants can soften and loosen the rhizosphere soil, which increases the evapotranspiration rate, the soil porosity, and absolute permeability and weakens the capillary effects. These, in turn, improve further the root aeration conditions and may lead to colonization by plants less resistant to anaerobic conditions.

  12. Organization of the 16th Advanced Accelerator Concepts (AAC) Workshop by Stanford University

    SciTech Connect

    Huang, Zhirong; Hogan, Mark

    2015-09-30

    Essentially all we know today and will learn in the future about the fundamental nature of matter is derived from probing it with directed beams of particles such as electrons, protons, neutrons, heavy ions, and photons. The resulting ability to “see” the building blocks of matter has had an immense impact on society and our standard of living. Over the last century, particle accelerators have changed the way we look at nature and the universe we live in and have become an integral part of the Nation’s technical infrastructure. Today, particle accelerators are essential tools of modern science and technology. The cost and capabilities of accelerators would be greatly enhanced by breakthroughs in acceleration methods and technology. For the last 32 years, the Advanced Accelerator Concepts (AAC) Workshop has acted as the focal point for discussion and development of the most promising acceleration physics and technology. It is a particularly effective forum where the discussion is leveraged and promoted by the unique and demanding feature of the AAC Workshop: the working group structure, in which participants are asked to consider their contributions in terms of even larger problems to be solved. The 16th Advanced Accelerator Concepts (AAC2014) Workshop was organized by Stanford University from July 13 - 18, 2014 at the Dolce Hays Mansion in San Jose, California. The conference had a record 282 attendees including 62 students. Attendees came from 11 countries representing 66 different institutions. The workshop format consisted of plenary sessions in the morning with topical leaders from around the world presenting the latest breakthroughs to the entire workshop. In the late morning and afternoons attendees broke out into eight different working groups for more detailed presentations and discussions that were summarized on the final day of the workshop. In addition, there were student tutorial presentations on two afternoons to provide in depth education and

  13. Copper-catalysed azide-alkyne cycloadditions (CuAAC): an update.

    PubMed

    Haldón, Estela; Nicasio, M Carmen; Pérez, Pedro J

    2015-10-01

    The reactions of organic azides and alkynes catalysed by copper species represent the prototypical examples of click chemistry. The so-called CuAAC reaction (copper-catalysed azide-alkyne cycloaddition), discovered in 2002, has been expanded since then to become an excellent tool in organic synthesis. In this contribution the recent results described in the literature since 2010 are reviewed, classified according to the nature of the catalyst precursor: copper(I) or copper(II) salts or complexes, metallic or nano-particulated copper and several solid-supported copper systems.

  14. Copper-catalysed azide-alkyne cycloadditions (CuAAC): an update.

    PubMed

    Haldón, Estela; Nicasio, M Carmen; Pérez, Pedro J

    2015-10-01

    The reactions of organic azides and alkynes catalysed by copper species represent the prototypical examples of click chemistry. The so-called CuAAC reaction (copper-catalysed azide-alkyne cycloaddition), discovered in 2002, has been expanded since then to become an excellent tool in organic synthesis. In this contribution the recent results described in the literature since 2010 are reviewed, classified according to the nature of the catalyst precursor: copper(I) or copper(II) salts or complexes, metallic or nano-particulated copper and several solid-supported copper systems. PMID:26284434

  15. ASME N510 test results for Savannah River Site AACS filter compartments

    SciTech Connect

    Paul, J.D.; Punch, T.M.

    1995-02-01

    The K-Reactor at the Savannah River Site recently implemented design improvements for the Airborne Activity Confinement System (AACS) by procuring, installing, and testing new Air Cleaning Units, or filter compartments, to ASME AG-11, N509, and N510 requirements. Specifically, these new units provide documentable seismic resistance to a Design Basis Accident earthquake, provide 2 inch adsorber beds with 0.25 second residence time, and meet all AG-1, N509, and N510 requirements for testability and maintainability. This paper presents the results of the Site acceptance testing and discusses an issue associated with sample manifold qualification testing.

  16. Analytical Results from the Area G Nitrate Salt Samples Submitted to C-AAC

    SciTech Connect

    Drake, Lawrence Randall

    2014-09-03

    Table 1 is a summary of the analysis results on sample 4174-1-6/7 and 4174-2-6/7. The results in Table 2 are the major and trace metals analysis values. Samples 4174-1-6 and 4174-2-7 were introduced into a radiological glovebox in CMR for partitioning and analysis. Samples 4174-1-7 and 4174-2-6 were assayed by gamma spectrometry and then sent to TA 48 (C-NR) for further analysis. The validated analytical procedures used by C-AAC are cited at the end of this document. The results have not been approved by formal QA release.

  17. Fault detection and isolation of sensors in aeration control systems.

    PubMed

    Carlsson, Bengt; Zambrano, Jesús

    2016-01-01

    In this paper, we consider the problem of fault detection (FD) and isolation in the aeration system of an activated sludge process. For this study, the dissolved oxygen in each aerated zone is assumed to be controlled automatically. As the basis for an FD method we use the ratio of air flow rates into different zones. The method is evaluated in two scenarios: using the Benchmark Simulation Model no. 1 (BSM1) by Monte Carlo simulations and using data from a wastewater treatment plant. The FD method shows good results for a correct and early FD and isolation.

  18. Retrofitting activated sludge systems to intermittent aeration for nitrogen removal.

    PubMed

    Hanhan, O; Artan, N; Orhon, D

    2002-01-01

    The paper provides the basis and the conceptual approach of applying process kinetics and modelling to the design of alternating activated sludge systems for retrofitting existing activated sludge plants to intermittent aeration for nitrogen removal. It shows the significant role of the two specific parameters, namely, the aerated fraction and the cycle time ratio on process performance through model simulations and proposes a way to incorporate them into a design procedure using process stoichiometry and mass balance. It illustrates the effect of these parameters, together with the sludge age, in establishing the balance between the denitrification potential and the available nitrogen created in the anoxic/aerobic sequences of system operation.

  19. Retrofitting activated sludge systems to intermittent aeration for nitrogen removal.

    PubMed

    Hanhan, O; Artan, N; Orhon, D

    2002-01-01

    The paper provides the basis and the conceptual approach of applying process kinetics and modelling to the design of alternating activated sludge systems for retrofitting existing activated sludge plants to intermittent aeration for nitrogen removal. It shows the significant role of the two specific parameters, namely, the aerated fraction and the cycle time ratio on process performance through model simulations and proposes a way to incorporate them into a design procedure using process stoichiometry and mass balance. It illustrates the effect of these parameters, together with the sludge age, in establishing the balance between the denitrification potential and the available nitrogen created in the anoxic/aerobic sequences of system operation. PMID:12420968

  20. Lunar concrete for construction

    NASA Technical Reports Server (NTRS)

    Cullingford, Hatice S.; Keller, M. Dean

    1992-01-01

    Feasibility of using concrete for lunar base construction was discussed recently without relevant data for the effects of vacuum on concrete. Our experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the Moon are provided in this paper, along with specific conclusions from the existing database.

  1. Lunar concrete for construction

    NASA Technical Reports Server (NTRS)

    Cullingford, Hatice S.; Keller, M. Dean

    1988-01-01

    Feasibility of using concrete for lunar-base construction has been discussed recently without relevant data for the effects of vacuum on concrete. Experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the moon are provided in this paper along with specific conclusions from the existing data base.

  2. Concrete radiation shielding

    SciTech Connect

    Kaplan, M.F.

    1989-01-01

    This book presents an introduction to the aspects of nuclear physics relevant to concrete technology. It covers a variety of materials that may be used to produce concrete for radiation shielding. Details of the physical, mechanical, and nuclear properties of these concretes are provided, and their applications in nuclear waste storage, shelter design, and reactor shielding are described. Radiation shield design considerations are addressed.

  3. Effect of cyclic aeration on fouling in submerged membrane bioreactor for wastewater treatment.

    PubMed

    Wu, Jun; He, Chengda

    2012-07-01

    Due to the inefficiency of aeration measures in preventing fouling by soluble and colloidal particles. The effect of alternating high/low cyclic aeration mode on the membrane fouling in the submerged membrane bioreactor was studied by comparing to fouling in a constant aeration mode. Results indicated a higher overall fouling rate in the cyclic aeration mode than in the constant aeration. However, a higher percentage of reversible fouling was observed for the cyclic aeration mode. The membrane permeability can be more easily recovered from physical cleaning such as backwashing in the cyclic aeration mode. The activated sludge floc size distribution analysis revealed a floc destruction and re-flocculation processes caused by the alternating high/low aeration. The short high aeration period could prevent the destruction of strong strength bonds within activated sludge flocs. Therefore, less soluble and colloidal material was observed in the supernatant due to the preservation of the strong strength bonds. The weak strength bonds damaged in the high aeration period could be recovered in the re-flocculation process in the low aeration period. The floc destruction and re-flocculation processes were suggested to be the main reason for the low irreversible fouling in the cyclic aeration mode.

  4. Intermittent aeration to improve wastewater treatment efficiency in pilot-scale constructed wetland.

    PubMed

    Uggetti, Enrica; Hughes-Riley, Theodore; Morris, Robert H; Newton, Michael I; Trabi, Christophe L; Hawes, Patrick; Puigagut, Jaume; García, Joan

    2016-07-15

    Forced aeration of horizontal subsurface flow constructed wetlands (HSSF CWs) is nowadays a recognized method to improve treatment efficiency, mainly in terms of ammonium removal. While numerous investigations have been reported testing constant aeration, scarce information can be found about the efficiency of intermittent aeration. This study aims at comparing continuous and intermittent aeration, establishing if there is an optimal regime that will increase treatment efficiency of HSSF CWs whilst minimizing the energy requirement. Full and intermittent aeration were tested in a pilot plant of three HSSF CWs (2.64m(2) each) fed with primary treated wastewater. One unit was fully aerated; one intermittently aerated (i.e. by setting a limit of 0.5mg/L dissolved oxygen within the bed) with the remaining unit not aerated as a control. Results indicated that intermittent aeration was the most successful operating method. Indeed, the coexistence of aerobic and anoxic conditions promoted by the intermittent aeration resulted in the highest COD (66%), ammonium (99%) and total nitrogen (79%) removals. On the other hand, continuous aeration promotes ammonium removal (99%), but resulted in nitrate concentrations in the effluent of up to 27mg/L. This study demonstrates the high potential of the intermittent aeration to increase wastewater treatment efficiency of CWs providing an extreme benefit in terms of the energy consumption.

  5. Dissolved Oxygen management in catfish ponds using electric paddlewheel aerators: new approaches with old technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The electric paddlewheel aerator has been the main aerator used in the U.S. catfish industry for the post forty years. While it has its limitations, it is perhaps the most efficient shallow-water aerator yet to be developed. Its shortcomings result not so much from poor design, as from poor usage. U...

  6. Poly(AAc-co-MBA) hydrogel films: adhesive and mechanical properties in aqueous medium.

    PubMed

    Arunbabu, Dhamodaran; Shahsavan, Hamed; Zhang, Wei; Zhao, Boxin

    2013-01-10

    Poly(acrylic acid-co-N,N'-methylenebisacrylamide) hydrogel films were synthesized by copolymerizing acrylic acid (AAc) with N,N'-methylenebisacrylamide (MBA) as a cross-linker via photo polymerization in the spacing confined between two glass plates. NMR spectroscopy was utilized to determine the cross-linking density. We found that the cross-linking density determined by NMR is higher than that expected from the feed concentrations of cross-linkers, suggesting that MBA is more reactive than AAc and the heterogeneous nature of the cross-linking. In addition to the swelling tests, indentation tests were performed on the hydrogel films under water to investigate effects of the cross-linking density on the adhesion and mechanical properties of the hydrogel films in terms of adhesive pull-off force and Hertz-type elastic modulus. As the cross-linker concentration increased, the effective elastic modulus of the hydrogel films increased dramatically at low cross-linking densities and reached a high steady-state value at higher cross-linking densities. The pull-off force decreased with increasing cross-linker concentration and reached a lower force plateau at high cross-linking densities. An optimal "trade-off" cross-linking density was determined to be 0.02 mol fraction of MBA in the hydrogel, where balanced elastic modulus and adhesive pull-off force can be obtained.

  7. Predicting language outcomes for children learning AAC: Child and environmental factors

    PubMed Central

    Brady, Nancy C.; Thiemann-Bourque, Kathy; Fleming, Kandace; Matthews, Kris

    2014-01-01

    Purpose To investigate a model of language development for nonverbal preschool age children learning to communicate with AAC. Method Ninety-three preschool children with intellectual disabilities were assessed at Time 1, and 82 of these children were assessed one year later at Time 2. The outcome variable was the number of different words the children produced (with speech, sign or SGD). Children’s intrinsic predictor for language was modeled as a latent variable consisting of cognitive development, comprehension, play, and nonverbal communication complexity. Adult input at school and home, and amount of AAC instruction were proposed mediators of vocabulary acquisition. Results A confirmatory factor analysis revealed that measures converged as a coherent construct and an SEM model indicated that the intrinsic child predictor construct predicted different words children produced. The amount of input received at home but not at school was a significant mediator. Conclusions Our hypothesized model accurately reflected a latent construct of Intrinsic Symbolic Factor (ISF). Children who evidenced higher initial levels of ISF and more adult input at home produced more words one year later. Findings support the need to assess multiple child variables, and suggest interventions directed to the indicators of ISF and input. PMID:23785187

  8. Forensic watermarking and bit-rate conversion of partially encrypted AAC bitstreams

    NASA Astrophysics Data System (ADS)

    Lemma, Aweke; Katzenbeisser, Stefan; Celik, Mehmet U.; Kirbiz, S.

    2008-02-01

    Electronic Music Distribution (EMD) is undergoing two fundamental shifts. The delivery over wired broadband networks to personal computers is being replaced by delivery over heterogeneous wired and wireless networks, e.g. 3G and Wi-Fi, to a range of devices such as mobile phones, game consoles and in-car players. Moreover, restrictive DRM models bound to a limited set of devices are being replaced by flexible standards-based DRM schemes and increasingly forensic tracking technologies based on watermarking. Success of these EMD services will partially depend on scalable, low-complexity and bandwidth eficient content protection systems. In this context, we propose a new partial encryption scheme for Advanced Audio Coding (AAC) compressed audio which is particularly suitable for emerging EMD applications. The scheme encrypts only the scale-factor information in the AAC bitstream with an additive one-time-pad. This allows intermediate network nodes to transcode the bitstream to lower data rates without accessing the decryption keys, by increasing the scale-factor values and re-quantizing the corresponding spectral coeficients. Furthermore, the decryption key for each user is customized such that the decryption process imprints the audio with a unique forensic tracking watermark. This constitutes a secure, low-complexity watermark embedding process at the destination node, i.e. the player. As opposed to server-side embedding methods, the proposed scheme lowers the computational burden on servers and allows for network level bandwidth saving measures such as multi-casting and caching.

  9. Children's ideas for the design of AAC assistive technologies for young children with complex communication needs.

    PubMed

    Light, Janice; Page, Rebecca; Curran, Jennifer; Pitkin, Laura

    2007-01-01

    This study examined children's preferences and priorities for the design of assistive technologies to enhance communication for children with complex communication needs. Six children without disabilities were provided with drawing and craft materials and were asked to develop low-tech prototypes of inventions to support the communication of a young child who had significant speech and motor impairments. The design process and the inventions were analyzed using qualitative methods. Results showed that the children's inventions differed significantly from the designs of current AAC technologies. Their inventions were not simply speech prostheses; rather, they integrated multiple functions (e.g., communication, social interaction, companionship, play, artistic expression, telecommunications) and provided dynamic contexts to support social interactions with others, especially peers. The children characterized the systems as companions and utilized innovative names, bright colors, lights, transformable shapes, popular themes, humor, and amazing accomplishments to capture interest, enhance appeal, build self-esteem, and establish a positive social image. The systems were easily personalized to reflect the user's age, personality, attitude, interests, and preferences. Re-designing AAC technologies to incorporate these types of functions and features may increase their appeal and make them easier for young children to learn and use. Results are discussed with reference to implications for future research and development. PMID:17852057

  10. 5. AERATOR VIEW FROM DOWNSTREAM. FLUSH VALVE AT RIGHT OPENS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. AERATOR VIEW FROM DOWNSTREAM. FLUSH VALVE AT RIGHT OPENS TO CLEAR THE SYSTEM ABOVE THE SILT AND DEBRIS AND TO STOP THE FLOW OF WATER INTO THE SYSTEM DOWN LINE. BOX FLUME CONTINUES DOWN LINE TO SEDIMENTATION CHAMBER. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

  11. Renewable energy for the aeration of wastewater ponds.

    PubMed

    Hobus, I; Hegemann, W

    2003-01-01

    The application of a decentralised renewable energy supply for the aeration of wastewater ponds, and the influence of an unsteady oxygen supply on the specific conversion rate and biocoenose was investigated. With the discontinuous aeration the specific conversion rate is increased as compared to facultative ponds. The estimation of the microorganisms consortia was done with in situ hybridisation techniques. A significant shift in the bacteria population with the chosen specific probes for anaerobic, sulphate reducing and nitrifying bacteria could not be detected. Wastewater ponds have sufficient buffer volume to compensate for the fluctuating energy supply. But the efficiency of the energy supply of a photovoltaic plant decreases in shallow lakes (d < 1.5 m) corresponding to a high oxygen production of algae. For the layout of the individual components: photovoltaic and wind power plant, energy management, aeration system and wastewater pond, a simulation model was developed and tested. The application of renewable energy for the aeration of wastewater ponds is a useful alternative for the redevelopment of overloaded ponds as well as the construction of new wastewater ponds, especially in areas with an inadequate central electricity grid and a high availability of wind and solar energy.

  12. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ethylene oxide gas aerator cabinet. 880.6100 Section 880.6100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... with a ventilation system designed to circulate and exchange the air in the cabinet to shorten the...

  13. Aerated Lagoons. Instructor's Guide. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Andersen, Lorri

    This unit (which consists of a single lesson) describes the structural and operationally unique features of aerated lagoons. In addition, special troubleshooting and maintenance problems are discussed. The instructor's guide for the unit includes: (1) an overview of the lesson; (2) lesson plan; (3) lecture outline (keyed to a set of slides used…

  14. 4. AERATOR AT 525, CONSTRUCTED 19371938, VIEW FROM UPSTREAM (TRASH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. AERATOR AT 525, CONSTRUCTED 1937-1938, VIEW FROM UPSTREAM (TRASH SCREEN REMOVED FOR CLARITY), WATER FROM INTAKE FLOWS THROUGH FLUME, THEN DAMS, AND SPILLS OVER STEPS TO MIX WITH OXYGEN, THUS REDUCING ACIDITY LEVELS. ACID INDUCES FASTER CORROSION OF PIPES AND SPOILS TASTE. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

  15. Landfill aeration for emission control before and during landfill mining.

    PubMed

    Raga, Roberto; Cossu, Raffaello; Heerenklage, Joern; Pivato, Alberto; Ritzkowski, Marco

    2015-12-01

    The landfill of Modena, in northern Italy, is now crossed by the new high velocity railway line connecting Milan and Bologna. Waste was completely removed from a part of the landfill and a trench for the train line was built. With the aim of facilitating excavation and further disposal of the material extracted, suitable measures were defined. In order to prevent undesired emissions into the excavation area, the aerobic in situ stabilisation by means of the Airflow technology took place before and during the Landfill Mining. Specific project features involved the pneumatic leachate extraction from the aeration wells (to keep the leachate table low inside the landfill and increase the volume of waste available for air migration) and the controlled moisture addition into a limited zone, for a preliminary evaluation of the effects on process enhancement. Waste and leachate were periodically sampled in the landfill during the aeration before the excavation, for quality assessment over time; the evolution of biogas composition in the landfill body and in the extraction system for different plant set-ups during the project was monitored, with specific focus on uncontrolled migration into the excavation area. Waste biological stability significantly increased during the aeration (waste respiration index dropped to 33% of the initial value after six months). Leachate head decreased from 4 to 1.5m; leachate recirculation tests proved the beneficial effects of moisture addition on temperature control, without hampering waste aerobization. Proper management of the aeration plant enabled the minimization of uncontrolled biogas emissions into the excavation area.

  16. 6. AERATOR VIEWED UPSTREAM. DETAIL OF FLUSH VALVE AND VIEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. AERATOR VIEWED UPSTREAM. DETAIL OF FLUSH VALVE AND VIEW INTO BOX FLUME. NOTE WRENCH TO OPEN VALVE AND REMAINS OF OLD SHOVEL USED FOR MAINTENANCE. TRASH SCREEN MESH IS SEEN AT BOTTOM LEFT. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

  17. The potential for aeration of MSW landfills to accelerate completion

    SciTech Connect

    Rich, Charlotte; Gronow, Jan; Voulvoulis, Nikolaos

    2008-07-01

    Landfilling is a popular waste disposal method, but, as it is practised currently, it is fundamentally unsustainable. The low short-term financial costs belie the potential long-term environmental costs, and traditional landfill sites require long-term management in order to mitigate any possible environmental damage. Old landfill sites might require aftercare for decades or even centuries, and in some cases remediation may be necessary. Biological stabilisation of a landfill is the key issue; completion criteria provide a yardstick by which the success of any new technology may be measured. In order for a site to achieve completion it must pose no risk to human health or the environment, meaning that attenuation of any emissions from the site must occur within the local environment without causing harm. Remediation of old landfill sites by aerating the waste has been undertaken in Germany, the United States, Italy and The Netherlands, with considerable success. At a pilot scale, aeration has also been used in newly emplaced waste to accelerate stabilisation. This paper reviews the use of aerobic landfill worldwide, and assesses the ways in which the use of aerobic landfill techniques can decrease the risks associated with current landfill practices, making landfill a more sustainable waste disposal option. It focuses on assessing ways to utilise aeration to enhance stabilisation. The results demonstrated that aeration of old landfill sites may be an efficient and cost-effective method of remediation and allow the date of completion to be brought forward by decades. Similarly, aeration of newly emplaced waste can be effective in enhancing degradation, assisting with completion and reducing environmental risks. However, further research is required to establish what procedure for adding air to a landfill would be most suitable for the UK and to investigate new risks that may arise, such as the possible emission of non-methane organic compounds.

  18. Numerical simulation of aeration bubble growth in a plug-flow aeration tank used in wastewater treatment

    NASA Astrophysics Data System (ADS)

    Wang, H. R.; Li, Y. P.

    2010-03-01

    The micro-scale hydrodynamics of bubbles growth by aeration is related to the oxygen transfer efficiency and the overall performance of the activated sludge wastewater treatment process. To gain a deeper insight on the micro-scale phenomena of dispersed bubble in this process, a three-dimensional direct simulation method is developed to study the effects of the liquid cross-flow on micro-scale behavior of bubble growth in a plug-flow aeration tank. The numerical simulations are performed using the level set method coupling with the governing equations of a single fluid with variable properties. The governing equations are solved using the finite-volume projection technique. The simulation results are compared with the experimental observations and theoretical relations. The simulated results show that water cross-flow in plug-flow type aeration tank has a strong impact on the bubble growth process. Compared to that generated under quiescent water conditions used in mixing type aeration tank, the bubble under water cross-flow conditions grows downstream along the tilted axis, and the bubble generation time tends to decrease noticeably and the bubble at detachment has significantly smaller size. The dynamic characteristics of the bubble growth through two orifices are also numerically studied. The effect of water cross-flow on the bubbling synchronicity is finally discussed.

  19. Effect of spray aeration on organics and nitrogen removal in vertical subsurface flow constructed wetland.

    PubMed

    Ding, Yi; Wang, Wei; Song, Xin-Shan; Wang, Gang; Wang, Yu-Hui

    2014-12-01

    The objective of present study was to assess the simultaneous removal of organics and nitrogen by four lab-scale vertical subsurface flow constructed wetlands (V-SFCWs). The emergent plants employed were Canna indica. Five-month experiments showed that the planted and aerated system largely reduced the COD by 95%, NH4 by 88% and total inorganic nitrogen (TIN) by 83%. It outperformed the unplanted or simple aerated system and was much better than non-aerated system. The study provided a strong evidence to support widespread research and application of spray aeration as a low-cost and energy-efficient aeration technology in V-SFCWs. PMID:25259785

  20. Effect of spray aeration on organics and nitrogen removal in vertical subsurface flow constructed wetland.

    PubMed

    Ding, Yi; Wang, Wei; Song, Xin-Shan; Wang, Gang; Wang, Yu-Hui

    2014-12-01

    The objective of present study was to assess the simultaneous removal of organics and nitrogen by four lab-scale vertical subsurface flow constructed wetlands (V-SFCWs). The emergent plants employed were Canna indica. Five-month experiments showed that the planted and aerated system largely reduced the COD by 95%, NH4 by 88% and total inorganic nitrogen (TIN) by 83%. It outperformed the unplanted or simple aerated system and was much better than non-aerated system. The study provided a strong evidence to support widespread research and application of spray aeration as a low-cost and energy-efficient aeration technology in V-SFCWs.

  1. A meta-synthesis of team members' voices: what we need and what we do to support students who use AAC.

    PubMed

    Chung, Yun-Ching; Stoner, Julia B

    2016-09-01

    The ultimate goal of AAC provision is to promote students' active participation across settings through interactions involving a variety of partners and functions. To achieve such outcomes, educational teams must collaborate and consider the characteristics of students, their families, and relevant environments during AAC assessment and intervention. To date, AAC team collaboration has rarely been evaluated collectively outside intervention or case study research. In this investigation, a meta-synthesis was conducted to review qualitative studies of perspectives of team members on supporting students who used AAC, ranging in age from kindergarten to post-secondary, in public schools in the United States. Analyses yielded three primary themes necessary for effective AAC services; inputs, activities, and outcomes. Implications and recommendations for service providers and future researchers are described. PMID:27615203

  2. Redox potential driven aeration during very-high-gravity ethanol fermentation by using flocculating yeast

    PubMed Central

    Liu, Chen-Guang; Hao, Xue-Mi; Lin, Yen-Han; Bai, Feng-Wu

    2016-01-01

    Ethanol fermentation requires oxygen to maintain high biomass and cell viability, especially under very-high-gravity (VHG) condition. In this work, fermentation redox potential (ORP) was applied to drive the aeration process at low dissolved oxygen (DO) levels, which is infeasible to be regulated by a DO sensor. The performance and characteristics of flocculating yeast grown under 300 and 260 g glucose/L conditions were subjected to various aeration strategies including: no aeration; controlled aeration at −150, −100 and −50 mV levels; and constant aeration at 0.05 and 0.2 vvm. The results showed that anaerobic fermentation produced the least ethanol and had the highest residual glucose after 72 h of fermentation. Controlled aerations, depending on the real-time oxygen demand, led to higher cell viability than the no-aeration counterpart. Constant aeration triggered a quick biomass formation, and fast glucose utilization. However, over aeration at 0.2 vvm caused a reduction of final ethanol concentration. The controlled aeration driven by ORP under VHG conditions resulted in the best fermentation performance. Moreover, the controlled aeration could enhance yeast flocculating activity, promote an increase of flocs size, and accelerate yeast separation near the end of fermentation. PMID:27161047

  3. Redox potential driven aeration during very-high-gravity ethanol fermentation by using flocculating yeast.

    PubMed

    Liu, Chen-Guang; Hao, Xue-Mi; Lin, Yen-Han; Bai, Feng-Wu

    2016-05-10

    Ethanol fermentation requires oxygen to maintain high biomass and cell viability, especially under very-high-gravity (VHG) condition. In this work, fermentation redox potential (ORP) was applied to drive the aeration process at low dissolved oxygen (DO) levels, which is infeasible to be regulated by a DO sensor. The performance and characteristics of flocculating yeast grown under 300 and 260 g glucose/L conditions were subjected to various aeration strategies including: no aeration; controlled aeration at -150, -100 and -50 mV levels; and constant aeration at 0.05 and 0.2 vvm. The results showed that anaerobic fermentation produced the least ethanol and had the highest residual glucose after 72 h of fermentation. Controlled aerations, depending on the real-time oxygen demand, led to higher cell viability than the no-aeration counterpart. Constant aeration triggered a quick biomass formation, and fast glucose utilization. However, over aeration at 0.2 vvm caused a reduction of final ethanol concentration. The controlled aeration driven by ORP under VHG conditions resulted in the best fermentation performance. Moreover, the controlled aeration could enhance yeast flocculating activity, promote an increase of flocs size, and accelerate yeast separation near the end of fermentation.

  4. Redox potential driven aeration during very-high-gravity ethanol fermentation by using flocculating yeast.

    PubMed

    Liu, Chen-Guang; Hao, Xue-Mi; Lin, Yen-Han; Bai, Feng-Wu

    2016-01-01

    Ethanol fermentation requires oxygen to maintain high biomass and cell viability, especially under very-high-gravity (VHG) condition. In this work, fermentation redox potential (ORP) was applied to drive the aeration process at low dissolved oxygen (DO) levels, which is infeasible to be regulated by a DO sensor. The performance and characteristics of flocculating yeast grown under 300 and 260 g glucose/L conditions were subjected to various aeration strategies including: no aeration; controlled aeration at -150, -100 and -50 mV levels; and constant aeration at 0.05 and 0.2 vvm. The results showed that anaerobic fermentation produced the least ethanol and had the highest residual glucose after 72 h of fermentation. Controlled aerations, depending on the real-time oxygen demand, led to higher cell viability than the no-aeration counterpart. Constant aeration triggered a quick biomass formation, and fast glucose utilization. However, over aeration at 0.2 vvm caused a reduction of final ethanol concentration. The controlled aeration driven by ORP under VHG conditions resulted in the best fermentation performance. Moreover, the controlled aeration could enhance yeast flocculating activity, promote an increase of flocs size, and accelerate yeast separation near the end of fermentation. PMID:27161047

  5. Lunar concrete: Prospects and challenges

    NASA Astrophysics Data System (ADS)

    Khitab, Anwar; Anwar, Waqas; Mehmood, Imran; Kazmi, Syed Minhaj Saleem; Munir, Muhammad Junaid

    2016-02-01

    The possibility of using concrete as a construction material at the Moon surface is considered. Dissimilarities between the Earth and the Moon and their possible effects on concrete are also emphasized. Availability of constituent materials for concrete at lunar surface is addressed. An emphasis is given to two types of materials, namely, hydraulic concrete and sulfur concrete. Hydraulic concrete necessitates the use of water and sulfur concrete makes use of molten sulfur in lieu of cement and water.

  6. Effective pine bark composting with the Dome Aeration Technology

    SciTech Connect

    Trois, Cristina . E-mail: troisc@ukzn.ac.za; Polster, Andreas

    2007-07-01

    In South Africa garden refuse is primarily disposed of in domestic landfills. Due to the large quantities generated, any form of treatment would be beneficial for volume reduction, waste stabilization and resource recovery. Dome Aeration Technology (DAT) is an advanced process for aerobic biological degradation of garden refuse and general waste [Paar, S., Brummack, J., Gemende, B., 1999a. Advantages of dome aeration in mechanical-biological waste treatment. In: Proceedings of the 7th International Waste Management and Landfill Symposium, Cagliari, 4-8 October 1999; Paar, S., Brummack, J., Gemende, B., 1999b. Mechanical-biological waste stabilization by the dome aeration method. Environment Protection Engineering 25 (3/99). Mollekopf, N., Brummack, J., Paar, S., Vorster, K., 2002. Use of the Dome Aeration Technology for biochemical stabilization of waste prior to landfilling. In: Proceedings of the Wastecon 2002, Waste Congress and Exhibition, Durban, South Africa.]. It is a non-reactor open windrow composting process, with the main advantage being that the input material needs no periodic turning. A rotting time of only 3-4 months indicates the high efficiency. Additionally, the low capital/operational costs, low energy inputs and limited plant requirements provide potential for use in aerobic refuse stabilization. The innovation in the DAT process is the passive aeration achieved by thermally driven advection through open windrows caused by temperature differences between the degrading material and the outside environment. This paper investigates the application of Dome Aeration Technology to pine bark composting as part of an integrated waste management strategy. A full-scale field experiment was performed at the Bisasar Road Landfill Site in Durban to assess the influence of climate, waste composition and operational conditions on the process. A test windrow was constructed and measurements of temperature and airflow through the material were taken. The process

  7. BIOVENTING - Groundwater Aeration by Discontinuous Oxygen Gas Pulse Injections

    NASA Astrophysics Data System (ADS)

    Schirmer, M.

    2003-12-01

    Groundwater aeration by discontinuous oxygen gas pulse injections appears to be a promising concept for enhanced natural attenuation of dissolved contaminants that are susceptible for oxygenase enzyme attacks. Oxygen amendments facilitate indigenous microbiota to catabolize groundwater pollutants, such as aromatics, that are considered to be recalcitrant in absence of dissolved oxygen. As a rule, natural attenuation of many pollutants under aerobic conditions is considerably faster than under anaerobic conditions. Thus, enhancing the dissolved oxygen level appears to be worthwhile. In situ aeration of groundwater has been accomplished by air sparging, H2O2-supply, or by utilization of oxygen release compounds. However, continuous aeration of previously anaerobic groundwater is not desirable for several reasons: (a) economic efforts too high, (b) pollutant dislocation towards surface (desired only in air sparging), (c) risk of aquifer clogging (gas clogging, oxidation of ferrous iron, formation of bioslimes). In contrast, discontinuous oxygen gas sparging provides only for periodical groundwater aeration which is followed by microaerobic and suboxic conditions. Microaerobic conditions can prevail spatially (e.g., at plume fringes or within biofilms) or temporarily (e.g., at discontinuous bioventing). They still allow adapted bacteria to transform environmental pollutants to less toxic compounds, e.g., aromatic ring cleavage after dioxygenasis attack. Ring cleavage products, on the other hand, may be degraded more easily by anaerobic consortia than the initial aromatic compounds, making oxygen depletion periods highly intriguing in regard to an initiation of natural attenuation processes at plume fringes. In our work we outline the effect of oxygen depletion conditions on biodegradation of monchlorobenzene (MCB) as they occur subsequently to temporary aeration periods. For microaerobic conditions, relative to the oxygen supply, a stoichiometric transformation of MCB

  8. Increasing the Literacy Skills of Students Who Require AAC through Modified Direct Instruction and Specific Instructional Feedback

    ERIC Educational Resources Information Center

    Westover, Jennifer M.

    2010-01-01

    Literacy skills are fundamental for all learners. For students who require augmentative and alternative communication (AAC), strong literacy skills provide a gateway to generative communication, genuine social networking, improved access to academic opportunities, access to information technology and future employment opportunities. However, many…

  9. Assessing Preferences for AAC Options in Communication Interventions for Individuals with Developmental Disabilities: A Review of the Literature

    ERIC Educational Resources Information Center

    van der Meer, Larah; Sigafoos, Jeff; O'Reilly, Mark F.; Lancioni, Giulio E.

    2011-01-01

    We synthesized studies that assessed preference for using different augmentative and alternative communication (AAC) options. Studies were identified via systematic searches of electronic databases, journals, and reference lists. Studies were evaluated in terms of: (a) participants, (b) setting, (c) communication options assessed, (d) design, (e)…

  10. Talking to Teenagers: Using Anthropological Methods to Explore Identity and the Lifeworlds of Young People Who Use AAC

    ERIC Educational Resources Information Center

    Wickenden, Mary

    2011-01-01

    The article outlines the methodology used in an ethnographic study of identity with teenagers who use augmentative and alternative communication (AAC). It is unusual to investigate this population in naturalistic contexts using qualitative methods. Nine individuals are studied, in a range of contexts using ethnography as the main method. The…

  11. Operational Demands of AAC Mobile Technology Applications on Programming Vocabulary and Engagement During Professional and Child Interactions.

    PubMed

    Caron, Jessica; Light, Janice; Drager, Kathryn

    2016-01-01

    Typically, the vocabulary in augmentative and alternative communication (AAC) technologies is pre-programmed by manufacturers or by parents and professionals outside of daily interactions. Because vocabulary needs are difficult to predict, young children who use aided AAC often do not have access to vocabulary concepts as the need and interest arises in their daily interactions, limiting their vocabulary acquisition and use. Ideally, parents and professionals would be able to add vocabulary to AAC technologies "just-in-time" as required during daily interactions. This study compared the effects of two AAC applications for mobile technologies: GoTalk Now (which required more programming steps) and EasyVSD (which required fewer programming steps) on the number of visual scene displays (VSDs) and hotspots created in 10-min interactions between eight professionals and preschool-aged children with typical development. The results indicated that, although all of the professionals were able to create VSDs and add vocabulary during interactions with the children, they created more VSDs and hotspots with the app with fewer programming steps than with the one with more steps, and child engagement and programming participation levels were high with both apps, but higher levels for both variables were observed with the app with fewer programming steps than with the one with more steps. These results suggest that apps with fewer programming steps may reduce operational demands and better support professionals to (a) respond to the child's input, (b) use just-in-time programming during interactions,

  12. Communication Input Matters: Lessons From Prelinguistic Children Learning to Use AAC in Preschool Environments.

    PubMed

    Brady, Nancy C; Herynk, James W; Fleming, Kandace

    2010-09-01

    This study reports on the communication produced by 30 children learning to communicate with AAC in their preschool classrooms, as well as the communication input provided by educators. All of the children were communicating with less than 20 different words, symbols, or signs at the time of observation. Characteristics of participants' preschool classrooms were also measured with the ECERS-R. Relationships between ECERS-R scores, communication input to children, and child communication rate were explored through correlation analyses. Results indicated that child communication rates in their classrooms were low and that the majority of child communication was in response to educators' initiations. Only the amount of adult input to children was significantly related to child communication rates. ECERS-R scores were not related to any observed communication variables. Results provide a base of comparison for future studies as well as demonstrating need to provide more communication input within preschool classrooms. PMID:21442020

  13. Communication Input Matters: Lessons From Prelinguistic Children Learning to Use AAC in Preschool Environments

    PubMed Central

    Brady, Nancy C.; Herynk, James W.; Fleming, Kandace

    2011-01-01

    This study reports on the communication produced by 30 children learning to communicate with AAC in their preschool classrooms, as well as the communication input provided by educators. All of the children were communicating with less than 20 different words, symbols, or signs at the time of observation. Characteristics of participants’ preschool classrooms were also measured with the ECERS-R. Relationships between ECERS-R scores, communication input to children, and child communication rate were explored through correlation analyses. Results indicated that child communication rates in their classrooms were low and that the majority of child communication was in response to educators’ initiations. Only the amount of adult input to children was significantly related to child communication rates. ECERS-R scores were not related to any observed communication variables. Results provide a base of comparison for future studies as well as demonstrating need to provide more communication input within preschool classrooms. PMID:21442020

  14. The substrate specificity of the human ADP/ATP carrier AAC1.

    PubMed

    Mifsud, John; Ravaud, Stéphanie; Krammer, Eva-Maria; Chipot, Chris; Kunji, Edmund R S; Pebay-Peyroula, Eva; Dehez, Francois

    2013-03-01

    The mitochondrial ADP/ATP carrier imports ADP from the cytosol into the mitochondrial matrix for its conversion to ATP by ATP synthase and exports ATP out of the mitochondrion to replenish the eukaryotic cell with chemical energy. Here the substrate specificity of the human mitochondrial ADP/ATP carrier AAC1 was determined by two different approaches. In the first the protein was functionally expressed in Escherichia coli membranes as a fusion protein with maltose binding protein and the effect of excess of unlabeled compounds on the uptake of [(32)P]-ATP was measured. In the second approach the protein was expressed in the cytoplasmic membrane of Lactococcus lactis. The uptake of [(14)C]-ADP in whole cells was measured in the presence of excess of unlabeled compounds and in fused membrane vesicles loaded with unlabeled compounds to demonstrate their transport. A large number of nucleotides were tested, but only ADP and ATP are suitable substrates for human AAC1, demonstrating a very narrow specificity. Next we tried to understand the molecular basis of this specificity by carrying out molecular-dynamics simulations with selected nucleotides, which were placed at the entrance of the central cavity. The binding of the phosphate groups of guanine and adenine nucleotides is similar, yet there is a low probability for the base moiety to be bound, likely to be rooted in the greater polarity of guanine compared to adenine. AMP is unlikely to engage fully with all contact points of the substrate binding site, suggesting that it cannot trigger translocation.

  15. Precise Orbital and Geodetic Parameter Estimation using SLR Observations for ILRS AAC

    NASA Astrophysics Data System (ADS)

    Kim, Young-Rok; Park, Eunseo; Oh, Hyungjik Jay; Park, Sang-Young; Lim, Hyung-Chul; Park, Chandeok

    2013-12-01

    In this study, we present results of precise orbital geodetic parameter estimation using satellite laser ranging (SLR) observations for the International Laser Ranging Service (ILRS) associate analysis center (AAC). Using normal point observations of LAGEOS-1, LAGEOS-2, ETALON-1, and ETALON-2 in SLR consolidated laser ranging data format, the NASA/ GSFC GEODYN II and SOLVE software programs were utilized for precise orbit determination (POD) and finding solutions of a terrestrial reference frame (TRF) and Earth orientation parameters (EOPs). For POD, a weekly-based orbit determination strategy was employed to process SLR observations taken from 20 weeks in 2013. For solutions of TRF and EOPs, loosely constrained scheme was used to integrate POD results of four geodetic SLR satellites. The coordinates of 11 ILRS core sites were determined and daily polar motion and polar motion rates were estimated. The root mean square (RMS) value of post-fit residuals was used for orbit quality assessment, and both the stability of TRF and the precision of EOPs by external comparison were analyzed for verification of our solutions. Results of post-fit residuals show that the RMS of the orbits of LAGEOS-1 and LAGEOS-2 are 1.20 and 1.12 cm, and those of ETALON-1 and ETALON-2 are 1.02 and 1.11 cm, respectively. The stability analysis of TRF shows that the mean value of 3D stability of the coordinates of 11 ILRS core sites is 7.0 mm. An external comparison, with respect to International Earth rotation and Reference systems Service (IERS) 08 C04 results, shows that standard deviations of polar motion XP and YP are 0.754 milliarcseconds (mas) and 0.576 mas, respectively. Our results of precise orbital and geodetic parameter estimation are reasonable and help advance research at ILRS AAC.

  16. Fly ash sulfur concrete

    SciTech Connect

    Head, W.J.; Liao, M.

    1981-05-01

    Two waste products, flyash and elemental sulfur, can be combined with a modifying agent to produce a potentially useful construction material, flyash sulfur concrete. Manufacturing processes and characteristics of this concrete are described. Compared with a conventional crushed stone aggregate, flyash sulfur concrete is a viable highway pavement base course material. The material's strength characteristics are analyzed. (1 diagram, 4 graphs, 2 photos, 9 references, 5 tables)

  17. Landfill aeration for emission control before and during landfill mining.

    PubMed

    Raga, Roberto; Cossu, Raffaello; Heerenklage, Joern; Pivato, Alberto; Ritzkowski, Marco

    2015-12-01

    The landfill of Modena, in northern Italy, is now crossed by the new high velocity railway line connecting Milan and Bologna. Waste was completely removed from a part of the landfill and a trench for the train line was built. With the aim of facilitating excavation and further disposal of the material extracted, suitable measures were defined. In order to prevent undesired emissions into the excavation area, the aerobic in situ stabilisation by means of the Airflow technology took place before and during the Landfill Mining. Specific project features involved the pneumatic leachate extraction from the aeration wells (to keep the leachate table low inside the landfill and increase the volume of waste available for air migration) and the controlled moisture addition into a limited zone, for a preliminary evaluation of the effects on process enhancement. Waste and leachate were periodically sampled in the landfill during the aeration before the excavation, for quality assessment over time; the evolution of biogas composition in the landfill body and in the extraction system for different plant set-ups during the project was monitored, with specific focus on uncontrolled migration into the excavation area. Waste biological stability significantly increased during the aeration (waste respiration index dropped to 33% of the initial value after six months). Leachate head decreased from 4 to 1.5m; leachate recirculation tests proved the beneficial effects of moisture addition on temperature control, without hampering waste aerobization. Proper management of the aeration plant enabled the minimization of uncontrolled biogas emissions into the excavation area. PMID:26445364

  18. Soil aeration status in a lowland wet grassland

    NASA Astrophysics Data System (ADS)

    Barber, K. R.; Leeds-Harrison, P. B.; Lawson, C. S.; Gowing, D. J. G.

    2004-02-01

    The maintenance or development of plant community diversity in species-rich wet grasslands has been a focus of water management considerations in the UK for the past 20 years. Much attention has been given to the control of water levels in the ditch systems within these wet grassland systems. In this paper we report measurements of aeration status and water-table fluctuation made on a peat soil site at Tadham Moor in Somerset, UK, where water management has focused on the maintenance of wet conditions that often result in flooding in winter and wet soil conditions in the spring and summer. Measurement and modelling of the water-table fluctuation indicates the possibility of variability in the aeration of the root environment and anoxic conditions for much of the winter period and for part of the spring and summer. We have used water content and redox potential measurements to characterize the aeration status of the peat soil. We find that air-filled porosity is related to water-table depth in these situations. Redox potentials in the spring were generally found to be low, implying a reducing condition for nitrate and iron. A significant relationship (p < 0.01) between redox potential and water-table depth exists for data measured at 0.1 m depth, but no relationship could be found for data from 0.4 m depth.

  19. Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits.

    PubMed

    Ozkan, Fahri; Tuna, M Cihat; Baylar, Ahmet; Ozturk, Mualla

    2014-01-01

    Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number. PMID:25225935

  20. Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits.

    PubMed

    Ozkan, Fahri; Tuna, M Cihat; Baylar, Ahmet; Ozturk, Mualla

    2014-01-01

    Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number.

  1. In situ nitrogen removal from leachate by bioreactor landfill with limited aeration

    SciTech Connect

    Shao Liming; He Pinjing Li Guojian

    2008-07-01

    The feasibility of simultaneous nitrification and denitrification in a bioreactor landfill with limited aeration was assessed. Three column reactors, simulating bioreactor landfill operations under anaerobic condition (as reference), intermittent forced aeration and enhanced natural aeration were hence established, where aerated columns passed through two phases, i.e., fresh landfill and well-decomposed landfill. The experimental results show that limited aeration decreased nitrogen loadings of leachate distinctly in the fresh landfill. In the well-decomposed landfill, the NH{sub 4}{sup +}-N of the input leachate could be nitrified completely in the aerated landfill columns. The nitrifying loadings of the column cross section reached 7.9 g N/m{sup 2} d and 16.9 g N/m{sup 2} d in the simulated landfill columns of intermittent forced aeration and enhanced natural aeration, respectively. The denitrification was influenced by oxygen distribution in the landfill column. Intermittent existence of oxygen in the landfill with the intermittent forced aeration was favorable to denitrify the NO{sub 2}{sup -}-N and NO{sub 3}{sup -}-N, indicated by the high denitrification efficiency (>99%) under the condition of BOD{sub 5}/TN of more than 5.4 in leachate; locally persistent existence of oxygen in the landfill with enhanced natural aeration could limit the denitrification, indicated by relatively low denitrification efficiency of about 75% even when the BOD{sub 5}/TN in leachate had an average of 7.1.

  2. Pleiotropic effects of the yeast Sal1 and Aac2 carriers on mitochondrial function via an activity distinct from adenine nucleotide transport

    PubMed Central

    Kucejova, Blanka; Li, Li; Wang, Xiaowen; Giannattasio, Sergio; Chen, Xin Jie

    2009-01-01

    In Saccharomyces cerevisiae, SAL1 encodes a Ca2+-binding mitochondrial carrier. Disruption of SAL1 is synthetically lethal with the loss of a specific function associated with the Aac2 isoform of the ATP/ADP translocase. This novel activity of Aac2 is defined as the V function (for Viability of aac2 sal1 double mutant), which is independent of the ATP/ADP exchange activity required for respiratory growth (the R function). We found that co-inactivation of SAL1 and AAC2 leads to defects in mitochondrial translation and mitochondrial DNA (mtDNA) maintenance. Additionally, sal1Δ exacerbates the respiratory deficiency and mtDNA instability of ggc1Δ, shy1Δ and mtg1Δ mutants, which are known to reduce mitochondrial protein synthesis or protein complex assembly. The V function is complemented by the human Short Ca2+-binding Mitochondrial Carrier (SCaMC) protein, SCaMC-2, a putative ATP-Mg/Pi exchangers on the inner membrane. However, mitochondria lacking both Sal1p and Aac2p are not depleted of adenine nucleotides. The Aac2R252I and Aac2R253I variants mutated at the R252-254 triplet critical for nucleotide transport retain the V function. Likewise, Sal1p remains functionally active when the R479I and R481I mutations were introduced into the structurally equivalent R479-T480-R481 motif. Finally, we found that the naturally occurring V-R+ Aac1 isoform of adenine nucleotide translocase partially gains the V function at the expense of the R function by introducing the mutations P89L and A96V. Thus, our data support the view that the V function is independent of adenine nucleotide transport associated with Sal1p and Aac2p and this evolutionarily conserved activity affects multiple processes in mitochondria. PMID:18431598

  3. A User and Their Family's Perspective of The Use of a Low-Tech Vs A High-Tech AAC System.

    PubMed

    Borg, S; Agius, M; Agius, L

    2015-01-01

    This qualitative case study describes a 9-year-old child, diagnosed with homonymous hemianopia, left side weakness and seizures that has been followed by Access to Communication and Technology Unit in Malta for 5 years. The child previously used a communication book and now uses an iPad as a speech generating device. A semi-structured interview was utilised with the parent to explore preference for each AAC system and the reasons for it. The impact of each AAC system on the family and on the child's communication skills, and perceived barriers in the implementation of the AACs were also explored. The child's own experience using the AAC systems was also investigated using a structured interview format. Talking Mats was used to support the child's understanding of the questions and to explore her perspectives on the two AAC systems using Yes-No responses. The parent interview was analysed thematically and represented visually using a thematic network. This was compared with child responses. Four organising themes emerged including barriers, benefits, facilitators, and expectations. Specific barriers included self-funding in order to provide the child with the best fit high-tech AAC. Perceived benefits for both AAC systems were that it increased her communicative intent. The child's mother perceived access to increased vocabulary and capacity for sentence building, operational autonomy as well as voice output as a benefit of the SGD. The child's results indicated a preference for the high-tech AAC because she found it easier to navigate than the low-tech AAC. PMID:26294568

  4. Antifouling marine concrete

    NASA Astrophysics Data System (ADS)

    Mathews, C. W.

    1980-03-01

    Various toxic agents were investigated for their ability to prevent the attachment and growth of marine fouling organisms on concrete. Three methods of incorporating antifoulants into concrete were also studied. Porous aggregate was impregnated with creosote and bis-(tri-n-butyltin) oxide (TBTO) and then used in making the concrete. Cuprous oxide, triphenyltin hydroxide (TPTH), and 2-2-bis-(p-methoxyphenyl)-1,1,1-trichloroethane (methoxychlor) were used as dry additives. Two proprietary formulations were applied as coatings on untreated concrete. Test specimens were exposed at Port Hueneme, Calif. and Key Biscayne, Fla. Efficacy of toxicants was determined by periodically weighing the specimens and the fouling organisms that became attached. Concrete prepared with an aggregate impregnated with a TBTO/creosote mixture demonstrated the best antifouling performance of those specimens exposed for more than 1 year. The two proprietary coatings and the concrete containing methoxychlor, TPTH, and cuprous oxide as dry additives have exhibited good antifouling properties but have been exposed for a shorter time. Also, the strength of concrete prepared using the toxicants was acceptable and the corrosion rate of reinforcing rods did not increase. The concentration of organotin compounds was essentially unchanged in a concrete specimen exposed 6-1/2 years in seawater.

  5. The effects of agitation and aeration on the production of gluconic acid by Aspergillus niger

    SciTech Connect

    Dronawat, S.N.; Svihla, C.K.; Hanley, T.R.

    1995-12-31

    The effects of agitation and aeration in the production of gluconic acid by Aspergillus niger from a glucose medium were investigated. Experiments were conducted at aeration rates of 5.0 and 10.0 L/min. Four different agitation speeds were investigated for each aeration rate. Gluconic acid concentration and biomass concentration were analyzed, and the rate of consumption of substrate by A. niger was noted. The main purpose of this work was to find the optimal conditions of agitation and aeration for the growth of A. niger and production of gluconic acid in submerged culture in a batch fermentor at a bench-top scale. The oxygen-transfer rates at different agitation and aeration rates were calculated. The gluconic acid concentration and rate of growth of A. niger increased with increase in the agitation and aeration rates.

  6. Stratification structure of polysaccharides and proteins in activated sludge with different aeration in membrane bioreactor.

    PubMed

    Zhang, Haifeng; Yu, Haihuan; Zhang, Lanhe; Song, Lianfa

    2015-09-01

    The effect of distribution pattern of polysaccharides (PS) and proteins (PN) in activated sludge (AS) stratification with different aeration rates on membrane fouling and rejection efficiency were investigated. During high aeration, PN and PS concentrations increased in supernatant, the dominant fraction (84% of PN and 73% of PS) was small molecules (<1 kDa). Less slime and loose bound extracellular polymeric substances (LB-EPS), more tight bound EPS (TB-EPS) were observed compared with low aeration. The decrease in PN/PS ratio and Ca(2+) concentration within EPS deteriorated AS flocculation ability. At slow trans-membrane pressure (TMP) rise stage, fouling rate under high aeration was 41% lower than low aeration due to lower PN within EPS outer. Low PS rejection rate (about 23%) leaded to higher PS in effluent at this stage. High PS rejection rate (about 94%) at rapid TMP rise stage resulted in about 2.2-time higher fouling rate than that low aeration.

  7. Effect of Aeration and Circulation Treatment of Effluent on Wastewater Purification Functions of a Planted Canal

    NASA Astrophysics Data System (ADS)

    Tsuji, Morio; Yamada, Kazuhiro; Hiratsuka, Akira

    Water purification characteristic evaluation was done for adding aeration and circulation to a canal planted with Carex dispalata, which is a Japanese native species whose height does not obstruct the view. Circulation improved the BOD removal efficiency, irrespective of the use of aeration. Aeration improved the BOD removal efficiency in the condition of circulation ON. The BOD removal rate without any circulation was 15g·m-2·d-1, which was the maximum, suggesting that it can be raised higher than 20g·m-2·d-1 through the use of aeration and circulation. The D-BOD removal effect is high. Therefore, removal of the organic pollution load by bacteria increased. The nitrogen removal efficiency did not increase because nitrification by aeration did not advance. Instead of energy-intensive aeration, it is necessary to consider the oxidative capacity of nitrification.

  8. Effects of aeration position on organics, nitrogen and phosphorus removal in combined oxidation pond-constructed wetland systems.

    PubMed

    Wang, Xiaoou; Tian, Yimei; Zhao, Xinhua; Peng, Sen; Wu, Qing; Yan, Lijian

    2015-12-01

    Given that few studies investigated the effects of aeration position (AP) on the performance of aerated constructed wetlands, the aim of this study was to evaluate the effects of AP on organics, nitrogen and phosphorus removal in lab-scale combined oxidation pond-constructed wetland (OP-CW) systems. Results showed that middle aeration allowed the CW to possess more uniform oxygen distribution and to achieve greater removals of COD and NH3-N, while the CW under bottom aeration and surface aeration demonstrated more distinct stratification of oxygen distribution and surface aeration brought about better TN removal capacity for the OP-CW system. However, no significant influence of artificial aeration or AP on TP removal was observed. Overall, AP could significantly affect the spatial distribution of dissolved oxygen by influencing the oxygen diffusion paths in aerated CWs, thereby influencing the removal of pollutants, especially organics and nitrogen, which offers a reference for the design of aerated CWs.

  9. Aeration-Induced Changes in Temperature and Nitrogen Dynamics in a Dimictic Lake.

    PubMed

    Holmroos, Heidi; Horppila, Jukka; Laakso, Sanna; Niemistö, Juha; Hietanen, Susanna

    2016-07-01

    Low levels of oxygen (O) in the hypolimnion layer of lakes are harmful to benthic animals and fish; they may also adversely affect nutrient cycles. Artificial aeration is often used in lake management to counteract these problems, but the effects of aeration on nitrogen (N) cycling are not known. We studied the effects of hypolimnetic aeration on N dynamics and temperature in a eutrophic lake by comparing continuous and pulsed aeration with a nonaerated station. Aeration decreased the accumulation of NH-N deep in the lake (20-33 m) by supplying O for nitrification, which in turn provided substrate for denitrification and promoted N removal. Aeration also increased the temperature in the hypolimnion. Denitrification rate was highest in the nonaerated deep areas (average, 7.62 mg N m d) due to very high rates during spring turnover of the water column, demonstrating that natural turnover provides O for nitrification. During stratification, denitrification was highest at the continuously aerated station (4.06 mg N m d) and lowest at the nonaerated station (3.02 mg N m d). At the periodically aerated station, aeration pauses did not restrict the increase in temperature but resulted in accumulation of NH-N and decreased the contribution of denitrification as a nitrate reduction process. Our findings demonstrate that hypolimnetic aeration can substantially affect N cycling in lakes and that the effect depends on the aeration strategy. Because N is one of the main nutrients controlling eutrophication, the effects of aeration methods on N removal should be considered as part of strategies to manage water quality in lakes.

  10. Aeration-Induced Changes in Temperature and Nitrogen Dynamics in a Dimictic Lake.

    PubMed

    Holmroos, Heidi; Horppila, Jukka; Laakso, Sanna; Niemistö, Juha; Hietanen, Susanna

    2016-07-01

    Low levels of oxygen (O) in the hypolimnion layer of lakes are harmful to benthic animals and fish; they may also adversely affect nutrient cycles. Artificial aeration is often used in lake management to counteract these problems, but the effects of aeration on nitrogen (N) cycling are not known. We studied the effects of hypolimnetic aeration on N dynamics and temperature in a eutrophic lake by comparing continuous and pulsed aeration with a nonaerated station. Aeration decreased the accumulation of NH-N deep in the lake (20-33 m) by supplying O for nitrification, which in turn provided substrate for denitrification and promoted N removal. Aeration also increased the temperature in the hypolimnion. Denitrification rate was highest in the nonaerated deep areas (average, 7.62 mg N m d) due to very high rates during spring turnover of the water column, demonstrating that natural turnover provides O for nitrification. During stratification, denitrification was highest at the continuously aerated station (4.06 mg N m d) and lowest at the nonaerated station (3.02 mg N m d). At the periodically aerated station, aeration pauses did not restrict the increase in temperature but resulted in accumulation of NH-N and decreased the contribution of denitrification as a nitrate reduction process. Our findings demonstrate that hypolimnetic aeration can substantially affect N cycling in lakes and that the effect depends on the aeration strategy. Because N is one of the main nutrients controlling eutrophication, the effects of aeration methods on N removal should be considered as part of strategies to manage water quality in lakes. PMID:27380085

  11. CFD study to determine the optimal configuration of aerators in a full-scale waste stabilization pond.

    PubMed

    Alvarado, Andres; Vesvikar, Mehul; Cisneros, Juan F; Maere, Thomas; Goethals, Peter; Nopens, Ingmar

    2013-09-01

    Aerated lagoons (ALs) are important variants of the pond wastewater treatment technology that have not received much attention in the literature. The hydraulic behaviour of ALs and especially the Facultative aerated lagoons (FALs) is very complex since the aeration in these systems is designed for oxygen transfer but not necessarily to create complete mixing. In this work, the energy expenditure of the aerators was studied by means of a scenario analysis. 3D CFD models (one phase and multiphase) of a 3 ha FAL in a waste stabilization pond system in Cuenca (Ecuador) were built for different configurations of aerators. The thrust produced by the aerators was modelled by an external momentum source applied as velocity vectors into the pond fluid. The predictions of a single phase model were in satisfactory agreement with experimental results. Subsequently, a scenario analysis assessing several aeration schemes with different numbers of aerators in operation were tested with respect to velocity profiles and residence time distribution (RTD) curves. This analysis showed that the aeration scheme with all 10 aerators switched on produces a similar hydraulic behaviour compared to using only 6 or 8 aerators. The current operational schemes comprise of switching off some aerators during the peak hours of the day and operating all 10 aerators during night. This current practice could be economically replaced by continuously operating 4 or 6 aerators without significantly affecting the overall mixing. Furthermore, a continuous mixing regime minimises the sediment oxygen demand enhancing the oxygen levels in the pond. PMID:23764602

  12. Bioreactor tests preliminary to landfill in situ aeration: A case study

    SciTech Connect

    Raga, Roberto; Cossu, Raffaello

    2013-04-15

    Highlights: ► Carbon and nitrogen mass balances in aerated landfill simulation reactors. ► Waste stabilization in aerated landfill simulation reactors. ► Effect of temperature on biodegradation processes in aerated landfills. - Abstract: Lab scale tests in bioreactor were carried out in the framework of the characterization studies of a landfill where in situ aeration (possibly followed by landfill mining) had been proposed as part of the novel waste management strategy in a region in northern Italy. The tests were run to monitor the effects produced by aerobic conditions at different temperatures on waste sampled at different depths in the landfill, with focus on the carbon and nitrogen conversion during aeration. Temperatures ranging from 35 to 45 °C were chosen, in order to evaluate possible inhibition of biodegradation processes (namely nitrification) at 45 °C in the landfill. The results obtained showed positive effects of the aeration on leachate quality and a significant reduction of waste biodegradability. Although a delay of biodegradation processes was observed in the reactor run at 45 °C, biodegradation rates increased after 2 months of aeration, providing very low values of the relevant parameters (as in the other aerated reactors) by the end of the study. Mass balances were carried out for TOC and N-NH{sub 4}{sup +}; the findings obtained were encouraging and provided evidence of the effectiveness of carbon and nitrogen conversion processes in the aerated landfill simulation reactors.

  13. Water quality and bacteriology in an aquaculture facility equipped with a new aeration system.

    PubMed

    Fernandes, Sheryl O; Kulkarni, Shantanu S; Shirodkar, Resha R; Karekar, Sheetal V; Kumar, R Praveen; Sreepada, R A; Vogelsang, Christian; Loka Bharathi, P A

    2010-05-01

    The HOBAS aeration system was tested to compare changes in environmental and bacteriological parameters in ponds growing Penaeus monodon during a single production cycle. The stocking density in the aerated pond was doubled to 12 post-larvae (PL) m(-2) in contrast to the non-aerated pond with 6 (PL) m(-2). Microbial abundance in the ponds ranged between 10(5-6) cells ml(-1). Among the physiological groups of bacteria enumerated, the heterotrophs dominated with an abundance of 10(4) CFU ml(-1). Of the nitrogen and sulfur cycle bacteria, the nitrifiers flourished in the aerated pond and could maintain ammonia-N concentration within permissible levels. Bacterial activity also maintained sulfide concentrations at < 0.03 mg l(-1). Non-aerated conditions promoted denitrification maintaining nitrate concentration between 0.32 and 0.98 microM NO(3)(-)-N l(-1). However, a marked increase in ammonium content was observed in the non-aerated pond at the end of the culture period. Thus in high-density ponds, the aerators served to stimulate bacterial growth and activity which consequently maintained the quality of the water to match that of low-density ponds. Accordingly, these aerators could be effectively used to sustain higher yields. The effluent from the aerated pond is less likely to alter the redox balance of the receiving waters.

  14. Landfill aeration in the framework of a reclamation project in Northern Italy.

    PubMed

    Raga, Roberto; Cossu, Raffaello

    2014-03-01

    In situ aeration by means of the Airflow technology was proposed for landfill conditioning before landfill mining in the framework of a reclamation project in Northern Italy. A 1-year aeration project was carried out on part of the landfill with the objective of evaluating the effectiveness of the Airflow technology for landfill aerobization, the evolution of waste biological stability during aeration and the effects on leachate and biogas quality and emissions. The main outcomes of the 1-year aeration project are presented in the paper. The beneficial effect of the aeration on waste biological stability was clear (63% reduction of the respiration index); however, the effectiveness of aeration on the lower part of the landfill is questionable, due to the limited potential for air migration into the leachate saturated layers. During the 1-year in situ aeration project approx. 275 MgC were discharged from the landfill body with the extracted gas, corresponding to 4.6 gC/kgDM. However, due to the presence of anaerobic niches in the aerated landfill, approx. 46% of this amount was extracted as CH4, which is higher than reported in other aeration projects. The O2 conversion quota was lower than reported in other similar projects, mainly due to the higher air flow rates applied. The results obtained enabled valuable recommendations to be made for the subsequent application of the Airflow technology to the whole landfill.

  15. [Effect of aeration intensity on the nitrogen and phosphorus removal performance of AOA membrane bioreactors].

    PubMed

    Chen, Xiao-Yang; Xue, Zhi-Yong; Xiao, Jing-Ni; Zhang, Han-Min; Yang, Feng-Lin; Wang, Wei-Ping; Hong, Chun-Lai; Zhu, Feng-Xiang

    2011-10-01

    The ability of simultaneous phosphorus and nitrogen removal of sequencing batch membrane bioreactor run in anaerobic/oxic/ anoxic mode (AOA MBR) was examined under three aeration intensities [2.5, 3.75 and 5.0 m3 x (m2 x h)(-10]. The results showed that the averaged removals of COD were over 90% at different aeration intensities. And the higher aeration intensity was, the more ammonia nitrogen removal rate achieved. The removal rates of NH4(+) under the three aeration intensities were 84.7%, 90.6% and 93.8%, respectively. Total nitrogen removal rate increased with the increasing aeration intensity. But excessive aeration intensity reduced TN removal. The removal rates of TN under the three aeration intensities were 83.4%, 87.4% and 80.6%, respectively. Aeration intensity affected the denitrifying phosphorus ability of the AOA MBR. The ratio of denitrification phosphorus removal under the three aeration intensities were 20%, 30.2% and 26.7%, respectively.

  16. Effect of influent aeration on removal of organic matter from coffee processing wastewater in constructed wetlands.

    PubMed

    Rossmann, Maike; Matos, Antonio Teixeira; Abreu, Edgar Carneiro; Silva, Fabyano Fonseca; Borges, Alisson Carraro

    2013-10-15

    The aim of the present study was to evaluate the influence of aeration and vegetation on the removal of organic matter in coffee processing wastewater (CPW) treated in 4 constructed wetlands (CWs), characterized as follows: (i) ryegrass (Lolium multiflorum) cultivated system operating with an aerated influent; (ii) non-cultivated system operating with an aerated influent, (iii) ryegrass cultivated system operating with a non-aerated influent; and (iv) non-cultivated system operating with a non-aerated influent. The lowest average chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) removal efficiencies of 87, 84 and 73%, respectively, were obtained in the ryegrass cultivated system operating with a non-aerated influent. However, ryegrass cultivation did not influence the removal efficiency of organic matter. Artificial aeration of the CPW, prior to its injection in the CW, did not improve the removal efficiencies of organic matter. On other hand it did contribute to increase the instantaneous rate at which the maximum COD removal efficiency was reached. Although aeration did not result in greater organic matter removal efficiencies, it is important to consider the benefits of aeration on the removal of the other compounds.

  17. Partial nitritation ANAMMOX in submerged attached growth bioreactors with smart aeration at 20 °C.

    PubMed

    Shannon, James M; Hauser, Lee W; Liu, Xikun; Parkin, Gene F; Mattes, Timothy E; Just, Craig L

    2015-01-01

    Submerged attached growth bioreactors (SAGBs) were operated at 20 °C for 30 weeks in smart-aerated, partial nitritation ANAMMOX mode and in a timer-controlled, cyclic aeration mode. The smart-aerated SAGBs removed 48-53% of total nitrogen (TN) compared to 45% for SAGBs with timed aeration. Low dissolved oxygen concentrations and cyclic pH patterns in the smart-aerated SAGBs suggested conditions favorable to partial nitritation ANAMMOX and stoichiometrically-derived and numerically modeled estimations attributed 63-68% and 14-44% of TN removal to partial nitritation ANAMMOX in these bioreactors, respectively. Ammonia removals of 36-67% in the smart-aerated SAGBs, with measured oxygen and organic carbon limitations, further suggest partial nitritation ANAMMOX. The smart-aerated SAGBs required substantially less aeration to achieve TN removals similar to SAGBs with timer-controlled aeration. Genomic DNA testing confirmed that the dominant ANAMMOX seed bacteria, received from a treatment plant utilizing the DEMON® sidestream deammonification process, was a Candidatus Brocadia sp. (of the Planctomycetales order). The DNA from these bacteria was also present in the SAGBs at the conclusion of the study providing evidence for attached growth and limited biomass washout.

  18. Method and apparatus for energy efficient self-aeration in chemical, biochemical, and wastewater treatment processes

    DOEpatents

    Gao, Johnway [Richland, WA; Skeen, Rodney S [Pendleton, OR

    2002-05-28

    The present invention is a pulse spilling self-aerator (PSSA) that has the potential to greatly lower the installation, operation, and maintenance cost associated with aerating and mixing aqueous solutions. Currently, large quantities of low-pressure air are required in aeration systems to support many biochemical production processes and wastewater treatment plants. Oxygen is traditionally supplied and mixed by a compressor or blower and a mechanical agitator. These systems have high-energy requirements and high installation and maintenance costs. The PSSA provides a mixing and aeration capability that can increase operational efficiency and reduce overall cost.

  19. Nitrogen-removal performance and community structure of nitrifying bacteria under different aeration modes in an oxidation ditch.

    PubMed

    Guo, Chang-Zi; Fu, Wei; Chen, Xue-Mei; Peng, Dang-Cong; Jin, Peng-Kang

    2013-07-01

    Oxidation-ditch operation modes were simulated using sequencing batch reactors (SBRs) with alternate stirring and aerating. The nitrogen-removal efficiencies and nitrifying characteristics of two aeration modes, point aeration and step aeration, were investigated. Under the same air-supply capacity, oxygen dissolved more efficiently in the system with point aeration, forming a larger aerobic zone. The nitrifying effects were similar in point aeration and step aeration, where the average removal efficiencies of NH4(+) N were 98% and 96%, respectively. When the proportion of anoxic and oxic zones was 1, the average removal efficiencies of total nitrogen (TN) were 45% and 66% under point aeration and step aeration, respectively. Step aeration was more beneficial to both anoxic denitrification and simultaneous nitrification and denitrification (SND). The maximum specific ammonia-uptake rates (AUR) of point aeration and step aeration were 4.7 and 4.9 mg NH4(+)/(gMLVSS h), respectively, while the maximum specific nitrite-uptake rates (NUR) of the two systems were 7.4 and 5.3 mg NO2(-)-N/(gMLVSS h), respectively. The proportions of ammonia-oxidizing bacteria (AOB) to all bacteria were 5.1% under point aeration and 7.0% under step aeration, and the proportions of nitrite-oxidizing bacteria (NOB) reached 6.5% and 9.0% under point and step aeration, respectively. The dominant genera of AOB and NOB were Nitrosococcus and Nitrospira, which accounted for 90% and 91%, respectively, under point aeration, and the diversity of nitrifying bacteria was lower than under step aeration. Point aeration was selective of nitrifying bacteria. The abundance of NOB was greater than that of AOB in both of the operation modes, and complete transformation of NH4(+) N to NO3(-)-N was observed without NO2(-)-N accumulation.

  20. Concrete sample point: 304 Concretion Facility

    SciTech Connect

    Rollison, M.D.

    1995-03-10

    This report contains information concerning the analysis of concretes for volatile organic compounds. Included are the raw data for these analysis and the quality control data, the standards data, and all of the accompanying chains-of-custody records and requests for special analysis.

  1. Inhibitors of the aminoglycoside 6'-N-acetyltransferase type Ib [AAC(6')-Ib] identified by in silico molecular docking.

    PubMed

    Lin, David L; Tran, Tung; Adams, Christina; Alam, Jamal Y; Herron, Steven R; Tolmasky, Marcelo E

    2013-10-15

    AAC(6')-Ib is an important aminoglycoside resistance enzyme to target with enzymatic inhibitors. An in silico screening approach was used to identify potential inhibitors from the ChemBridge library. Several compounds were identified, of which two of them, 4-[(2-{[1-(3-methylphenyl)-4,6-dioxo-2-thioxotetrahydro-5(2H)-pyrimidinylidene]methyl}phenoxy)methyl]benzoic acid and 2-{5-[(4,6-dioxo-1,3-diphenyl-2-thioxotetrahydro-5(2H)-pyrimidinylidene)methyl]-2-furyl}benzoic acid, showed micromolar activity in inhibiting acetylation of kanamycin A. These compounds are predicted to bind the aminoglycoside binding site of AAC(6')-Ib and exhibited competitive inhibition against kanamycin A.

  2. So you want to work? What employers say about job skills, recruitment and hiring employees who rely on AAC.

    PubMed

    Bryen, Diane Nelson; Potts, Blyden B; Carey, Allison C

    2007-06-01

    In order to better understand employer perspectives with respect to hiring and working with people who use AAC and the kinds of employment barriers they believe exist for these individuals, a study into the job requirements, recruitment processes, and hiring processes of 27 employers in the United States was conducted. Interviews with the 27 employers focused on 48 jobs in 25 unique categories, many of which had previously been identified as desirable by 38 adults who used AAC (some of whom were employed and some of whom were seeking employment). Findings suggest that, while level of education is still important to employers, skills such as time management, problem solving, communication, use of an understandable and standard voice, and basic technology may be even more so. The study also found that having an effective job-related network is important, as is the ability to provide credible references and do well during in-person interviews with potential employers.

  3. Au-iClick mirrors the mechanism of copper catalyzed azide–alkyne cycloaddition (CuAAC)

    SciTech Connect

    Powers, Andrew R.; Ghiviriga, Ion; Abboud, Khalil A.; Veige, Adam S.

    2015-07-20

    This report outlines the investigation of the iClick mechanism between gold(I)-azides and gold(I)-acetylides to yield digold triazolates. Isolation of digold triazolate complexes offer compelling support for the role of two copper(I) ions in CuAAC. In addition, a kinetic investigation reveals the reaction is first order in both Au(I)-N3 and Au(I)-C≡C-R equivalent to C-R, thus second order overall. A Hammett plot with a ρ = 1.02(5) signifies electron-withdrawing groups accelerate the cycloaddition by facilitating the coordination of the second gold ion in a π-complex. Rate inhibition by the addition of free triphenylphosphine to the reaction indicates that ligand dissociation is a prerequisite for the reaction. The mechanistic conclusions mirror those proposed for the CuAAC reaction.

  4. Au-iClick mirrors the mechanism of copper catalyzed azide–alkyne cycloaddition (CuAAC)

    DOE PAGES

    Powers, Andrew R.; Ghiviriga, Ion; Abboud, Khalil A.; Veige, Adam S.

    2015-07-20

    This report outlines the investigation of the iClick mechanism between gold(I)-azides and gold(I)-acetylides to yield digold triazolates. Isolation of digold triazolate complexes offer compelling support for the role of two copper(I) ions in CuAAC. In addition, a kinetic investigation reveals the reaction is first order in both Au(I)-N3 and Au(I)-C≡C-R equivalent to C-R, thus second order overall. A Hammett plot with a ρ = 1.02(5) signifies electron-withdrawing groups accelerate the cycloaddition by facilitating the coordination of the second gold ion in a π-complex. Rate inhibition by the addition of free triphenylphosphine to the reaction indicates that ligand dissociation is amore » prerequisite for the reaction. The mechanistic conclusions mirror those proposed for the CuAAC reaction.« less

  5. Flight Testing of the Space Launch System (SLS) Adaptive Augmenting Control (AAC) Algorithm on an F/A-18

    NASA Technical Reports Server (NTRS)

    Dennehy, Cornelius J.; VanZwieten, Tannen S.; Hanson, Curtis E.; Wall, John H.; Miller, Chris J.; Gilligan, Eric T.; Orr, Jeb S.

    2014-01-01

    The Marshall Space Flight Center (MSFC) Flight Mechanics and Analysis Division developed an adaptive augmenting control (AAC) algorithm for launch vehicles that improves robustness and performance on an as-needed basis by adapting a classical control algorithm to unexpected environments or variations in vehicle dynamics. This was baselined as part of the Space Launch System (SLS) flight control system. The NASA Engineering and Safety Center (NESC) was asked to partner with the SLS Program and the Space Technology Mission Directorate (STMD) Game Changing Development Program (GCDP) to flight test the AAC algorithm on a manned aircraft that can achieve a high level of dynamic similarity to a launch vehicle and raise the technology readiness of the algorithm early in the program. This document reports the outcome of the NESC assessment.

  6. Electrokinetic decontamination of concrete

    SciTech Connect

    Lomasney, H.L.; SenGupta, A.K.; Yachmenev, V.

    1996-12-31

    ELECTROSORB Electrokinetic Extraction Technology, developed by ISOTRON Corp., offers a cost-effective approach to treating contaminated concrete. Heavy metals/radionuclides trapped in concrete can be extracted using this process if they are chemically solubilized; solubilizers used are citric acid alone and a mixture of citric and nitric acids. A DC electric field is applied across the contaminated concrete to electrokinetically transport the solubilized contaminants from the concrete pores to a collector on the concrete surface. The collector is an extraction pad laid on the surface. The pad provides confinement for a planar electrode and solubilizer solution; it is operated under a vacuum to hold the pad against the concrete surface. Operation requires little attendance, reducing the workers` health hazards. The process incorporates a mechanism for recycling the solubilizer solution. A field demonstration of the process took place in Building 21 of DOE`s Mound facility in Miamisburg, OH, over 12 days in June 1996. The thorium species present in this building`s concrete floors included ThO{sub 2} and thorium oxalate. The nitric acid was found to facilitate Th extraction.

  7. Performance of Waterless Concrete

    NASA Technical Reports Server (NTRS)

    Toutanji, Houssam; Evans, Steve; Grugel, Richard N.

    2010-01-01

    The development of permanent lunar bases is constrained by performance of construction materials and availability of in-situ resources. Concrete seems a suitable construction material for the lunar environment, but water, one of its major components, is an extremely scarce resource on the Moon. This study explores an alternative to hydraulic concrete by replacing the binding mix of concrete (cement and water) with sulfur. Sulfur is a volatile element on the lunar surface that can be extracted from lunar soils by heating. Sulfur concrete mixes were prepared to investigate the effect of extreme environmental conditions on the properties of sulfur concrete. A hypervelocity impact test was conducted, having as its target a 5-cm cubic sample of sulfur concrete. This item consisted of JSC-1 lunar regolith simulant (65%) and sulfur (35%). The sample was placed in the MSFC Impact Test Facility s Micro Light Gas Gun target chamber, and was struck by a 1-mm diameter (1.4e-03 g) aluminum projectile at 5.85 km/s. In addition, HZTERN code, provided by NASA was used to study the effectiveness of sulfur concrete when subjected to space radiation.

  8. Antifouling marine concrete

    SciTech Connect

    Vind, H P; Mathews, C W

    1980-07-01

    Various toxic agents were evaluated as the their capability to prevent or inhibit the attachment of marine fouling organisms to concrete. Creosote and bis-(tri-n-butyltin) oxide (TBTO) were impregnated into porous aggregate which was used in making concrete. Cuprous oxide, triphenyltin hydroxide (TPTH), and 2-2-bis-(p-methoxyphenyl)-1,1,1-trichloroethane (methoxychlor) were used as dry additives. Two proprietary formulations were applied as coatings on untreated concrete. Test specimens were exposed at Port Hueneme, CA, and Key Biscayne, FL. The efficacy of toxicants was determined by periodically weighing the adhering fouling organisms. Concrete prepared with an aggregate impregnated with a TBTO/creosote mixture has demonstrated the best antifouling performance of those specimens exposed for more than one year. The two proprietary coatings and the concrete containing methoxychlor, TPTH, and cuprous oxide as dry additives have exhibited good antifouling properties, but they have been exposed for a shorter time. The strength of concrete containing the toxicants was acceptable, and the toxicants did not increase the corrosion rate of reinforcing rods. Organotin compounds were essentially unchanged in concrete specimens exposed 6 1/2 years in seawater.

  9. Antifouling marine concrete

    SciTech Connect

    Vind, H P; Mathews, C W

    1980-07-01

    Various toxic agents were evaluated as to their capability to prevent or inhibit the attachment of marine fouling organisms to concrete for OTEC plants. Creosote and bis-(tri-n-butyltin) oxide (TBTO) were impregnated into porous aggregate which was used in making concrete. Cuprous oxide, triphenyltin hydroxide (TPTH), and 2-2-bis-(p-methoxyphenyl)-1,1,1-trichloroethane (methoxychlor) were used as dry additives. Two proprietary formulations were applied as coatings on untreated concrete. Test specimens were exposed at Port Hueneme, CA, and Key Biscayne, FL. The efficacy of toxicants was determined by periodically weighing the adhering fouling organisms. Concrete prepared with an aggregate impregnated with a TBTO/creosote mixture has demonstrated the best antifouling performance of those specimens exposed for more than one year. The two proprietary coatings and the concrete containing methoxychlor, TPTH, and cuprous oxide as dry additives have exhibited good antifouling properties, but they have been exposed for a shorter time. The strength of concrete containing the toxicants was acceptable, and the toxicants did not increase the corrosion rate of reinforcing rods. Organotin compounds were essentially unchanged in concrete specimens exposed 6-1/2 years in seawater.

  10. Kinetics of bulk photo-initiated copper(i)-catalyzed azide–alkyne cycloaddition (CuAAC) polymerizations†

    PubMed Central

    Song, Han Byul; Baranek, Austin; Bowman, Christopher N.

    2016-01-01

    Photoinitiation of polymerizations based on the copper(i)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction enables spatio-temporal control and the formation of mechanically robust, highly glassy photopolymers. Here, we investigated several critical factors influencing photo-CuAAC polymerization kinetics via systematic variation of reaction conditions such as the physicochemical nature of the monomers; the copper salt and photoinitiator types and concentrations; light intensity; exposure time and solvent content. Real time Fourier transform infrared spectroscopy (FTIR) was used to monitor the polymerization kinetics in situ. Six different di-functional azide monomers and four different tri-functional alkyne monomers containing either aliphatic, aromatic, ether and/or carbamate substituents were synthesized and polymerized. Replacing carbamate structures with ether moieties in the monomers enabled an increase in conversion from 65% to 90% under similar irradiation conditions. The carbamate results in stiffer monomers and higher viscosity mixtures indicating that chain mobility and diffusion are key factors that determine the CuAAC network formation kinetics. Photoinitiation rates were manipulated by altering various aspects of the photo-reduction step; ultimately, a loading above 3 mol% per functional group for both the copper catalyst and the photoinitiator showed little or no rate dependence on concentration while a loading below 3 mol% exhibited 1st order rate dependence. Furthermore, a photoinitiating system consisting of camphorquinone resulted in 60% conversion in the dark after only 1 minute of 75 mW cm−2 light exposure at 400–500 nm, highlighting a unique characteristic of the CuAAC photopolymerization enabled by the combination of the copper(i)’s catalytic lifetime and the nature of the step-growth polymerization. PMID:27429650

  11. N,N'-Dialkylaminoalkylcarbonyl (DAAC) prodrugs and aminoalkylcarbonyl (AAC) prodrugs of 4-hydroxyacetanilide and naltrexone with improved skin permeation properties.

    PubMed

    Devarajan-Ketha, H; Sloan, K B

    2011-07-01

    N,N'-Dialkylaminoalkylcarbonyl (DAAC) and aminoalkylcarbonyl (AAC) prodrugs of phenolic drugs acetaminophen (APAP) and naltrexone (NTX) are reported. The effects of incorporation of a basic amine group into the promoiety of an acyl prodrug of a phenolic drug on its skin permeation properties are also presented. DAAC-APAP prodrugs were synthesized via a three-step procedure starting with haloalkylcarbonyl esters which were reacted with five different amines: dimethylamine, diethylamine, dipropylamine, morpholine, and piperidine. The spacing between the amino group and the carbonyl group of the acyl group was 1-3 CH(2). After the hydrolysis of the ester, the carboxylic acid product was subsequently coupled with the parent drug via a dicyclohexyl carbodiimide (DCC) mediated coupling to yield the DAAC-APAP-HCl prodrugs in excellent yields. The AAC prodrugs were synthesized using commercially available Boc-protected amino acids using DCC or EDCI as coupling agents. The yields of the prodrugs synthesized using these two different methods have been compared. Half-lives (t(1/2)) of a few members of the DAAC and AAC series were measured in buffer (pH 6.0, 20mM). The members evaluated in hydrolysis experiments exhibit a t(1/2) range of 15-113min. Among AAC-APAP prodrugs, the isopropyl group in valinate-APAP-HCl exerted a steric effect that increased the t(1/2) value for this prodrug compared to alaninate-APAP-HCl or prolinate-APAP-HCl. The 2-morpholinylacetate-APAP prodrug was able to achieve twice the flux of APAP in in vitro diffusion cell experiments through hairless mouse skin. PMID:21616664

  12. Recent Advances in Recoverable Systems for the Copper-Catalyzed Azide-Alkyne Cycloaddition Reaction (CuAAC).

    PubMed

    Mandoli, Alessandro

    2016-01-01

    The explosively-growing applications of the Cu-catalyzed Huisgen 1,3-dipolar cycloaddition reaction between organic azides and alkynes (CuAAC) have stimulated an impressive number of reports, in the last years, focusing on recoverable variants of the homogeneous or quasi-homogeneous catalysts. Recent advances in the field are reviewed, with particular emphasis on systems immobilized onto polymeric organic or inorganic supports. PMID:27607998

  13. Biodecontamination of concrete

    SciTech Connect

    Hamilton, M.A.; Rogers, R.D.; Benson, J.

    1996-12-31

    A novel technology for biologically decontaminating concrete is being jointly developed by scientists at the Idaho National Engineering Laboratory (INEL) and British Nuclear Fuels plc (BNFL). The technology exploits a naturally occurring phenomenon referred to as microbially influenced degradation (MID) in which bacteria produce acids that dissolve the cement matrix of concrete. Most radionuclide contamination of concrete is fixed in the outer few mm of the concrete surface. By capturing and controlling this natural process, a biological method of removing the surface of concrete to depths up to several mm is being developed. Three types of bacteria are known to be important in MID of concrete: nitrifying bacteria that produce nitric acid, sulfur oxidizing bacteria that produce sulfuric acid, and certain heterotrophic bacteria that produce organic acids. An investigation of natural environments demonstrated with scanning electron microscopy the presence of bacteria on concrete surfaces of a variety of structures, such as bridges and dams, where corrosion is evident. Enumeration of sulfur oxidizing and nitrifying bacteria revealed their presence and activity on structures to varying degrees in different environments. Under ideal conditions, Thiobacillus thiooxidans, a sulfur oxidizing bacteria, attached to and colonized the surface of concrete specimens. Over 1mm depth of material from a 10 cm x 10 cm square surface was removed in 68 days in the Thiobacillus treated specimen compared to a sterile control. Laboratory and field demonstrations are currently being conducted using experimental chambers designed to be mounted directly to concrete surfaces where radionuclide contamination exists. Data is being obtained in order to determine actual rates of surface removal and limitations to the system. This information will be used to develop a full scale decontamination technology.

  14. Biologically induced concrete deterioration in a wastewater treatment plant assessed by combining microstructural analysis with thermodynamic modeling

    SciTech Connect

    Leemann, A.; Lothenbach, B.; Hoffmann, C.

    2010-08-15

    In the nitrification basins of wastewater treatment plants, deterioration of the concrete surface can occur due to acid attack caused by a nitrifying biofilm covering the concrete. To identify the mechanism of deterioration, concrete cubes of different composition were suspended in an aerated nitrification basin of a wastewater treatment plant for two years and analyzed afterwards. The microstructural investigation reveals that not only dissolution of hydrates takes place, but that calcite precipitation close to the surface occurs leading to the formation of a dense layer. The degree of deterioration of the different cubes correlates with the CaO content of the different cements used. Cements which contain a high fraction of CaO form more calcite offering a better protection against the acid attack. The presence of slag, which lowers the amount CaO in the cement, leads to a faster deterioration of the concrete than observed for samples produced with pure OPC.

  15. Pseudomonads Rule Degradation of Polyaromatic Hydrocarbons in Aerated Sediment

    PubMed Central

    Wald, Jiri; Hroudova, Miluse; Jansa, Jan; Vrchotova, Blanka; Macek, Tomas; Uhlik, Ondrej

    2015-01-01

    Given that the degradation of aromatic pollutants in anaerobic environments such as sediment is generally very slow, aeration could be an efficient bioremediation option. Using stable isotope probing (SIP) coupled with pyrosequencing analysis of 16S rRNA genes, we identified naphthalene-utilizing populations in aerated polyaromatic hydrocarbon (PAH)-polluted sediment. The results showed that naphthalene was metabolized at both 10 and 20°C following oxygen delivery, with increased degradation at 20°C as compared to 10°C—a temperature more similar to that found in situ. Naphthalene-derived 13C was primarily assimilated by pseudomonads. Additionally, Stenotrophomonas, Acidovorax, Comamonas, and other minor taxa were determined to incorporate 13C throughout the measured time course. The majority of SIP-detected bacteria were also isolated in pure cultures, which facilitated more reliable identification of naphthalene-utilizing populations as well as proper differentiation between primary consumers and cross-feeders. The pseudomonads acquiring the majority of carbon were identified as Pseudomonas veronii and Pseudomonas gessardii. Stenotrophomonads and Acidovorax defluvii, however, were identified as cross-feeders unable to directly utilize naphthalene as a growth substrate. PAH degradation assays with the isolated bacteria revealed that all pseudomonads as well as Comamonas testosteroni degraded acenaphthene, fluorene, and phenanthrene in addition to naphthalene. Furthermore, P. veronii and C. testosteroni were capable of transforming anthracene, fluoranthene, and pyrene. Screening of isolates for naphthalene dioxygenase genes using a set of in-house designed primers for Gram-negative bacteria revealed the presence of such genes in pseudomonads and C. testosteroni. Overall, our results indicated an apparent dominance of pseudomonads in the sequestration of carbon from naphthalene and potential degradation of other PAHs upon aeration of the sediment at both 20 and

  16. [Biological phosphorus removal in intermittent aerated biological filter].

    PubMed

    Zeng, Long-Yun; Yang, Chun-Ping; Guo, Jun-Yuan; Luo, Sheng-Lian

    2012-01-01

    Under intermittent aerated and continuous fed operation where the biofilm system was subjected to alternated anaerobic/aerobic condition, the effect of influent volatile fatty acids (VFAs) concentrations, operation cycle and backwash on the biological phosphorus removal performance of the biofilter was studied. In the experiment, synthetic domestic wastewater was used, and the influent velocity was 5 L x h(-1) with gas versus liquid ratio of 8:1 and hydraulic retention time (HRT) of 1.3 h, resulting in average COD, ammonium and phosphorus load of 4.7, 0.41 and 0.095 g x (L x d) (-1) respectively. Results show that, (1) effective release and uptake of phosphorus was achieved in a operation cycle; (2) when influent VFAs was 100 mg x L(-1) (calculated by COD value) and operation cycle was 6 h the filter performed best in phosphorus removal, the phosphorus loading removal rate can be as much as 0.059 g x (L x d)(-1) at the aerated phase with those of COD and ammonium being 3.8 g x (L x d)(-1) and 0.28 g x (L x d)(-1) respectively, and with average effluent phosphorus, COD and ammonium concentrations being 1.8, 43.6 and 8.7 mg x L(-1), which shows nitrogen loss also happened; (3) the pause of backwash decreased the phosphorus removal performance rapidly with the removal efficiency lower than 40% in two days, but the consequent daily backwash operation gave a short improvement on the phosphorus removal, which disappeared in another two days. Thus, it is shown that biological phosphorus removal achieved with better phosphorus loading removal performance in the biofilter under intermittent aerated and continuous fed operation, and that sufficient and stable influent VFAs concentration, proper operation cycle, and more frequent backwash favored the performance.

  17. Advancements in text-to-speech technology and implications for AAC applications

    NASA Astrophysics Data System (ADS)

    Syrdal, Ann K.

    2003-10-01

    Intelligibility was the initial focus in text-to-speech (TTS) research, since it is clearly a necessary condition for the application of the technology. Sufficiently high intelligibility (approximating human speech) has been achieved in the last decade by the better formant-based and concatenative TTS systems. This led to commercially available TTS systems for highly motivated users, particularly the blind and vocally impaired. Some unnatural qualities of TTS were exploited by these users, such as very fast speaking rates and altered pitch ranges for flagging relevant information. Recently, the focus in TTS research has turned to improving naturalness, so that synthetic speech sounds more human and less robotic. Unit selection approaches to concatenative synthesis have dramatically improved TTS quality, although at the cost of larger and more complex systems. This advancement in naturalness has made TTS technology more acceptable to the general public. The vocally impaired appreciate a more natural voice with which to represent themselves when communicating with others. Unit selection TTS does not achieve such high speaking rates as the earlier TTS systems, however, which is a disadvantage to some AAC device users. An important new research emphasis is to improve and increase the range of emotional expressiveness of TTS.

  18. Eyetracked optical see-through head-mounted display as an AAC device

    NASA Astrophysics Data System (ADS)

    Hua, Hong; Hu, Xinda; Gao, Chunyu; Qin, Xiao

    2014-06-01

    An eye-tracked head-mounted display (ET-HMD) system is able to display virtual images as a classical headmounted display (HMD) does, while additionally tracking the gaze direction of the user. An HMD with fullyintegrated eyetracking capability offers multi-fold benefits, not only to fundamental scientific research but also to emerging applications of such technology. A key limitation of the state-of-the-art ET-HMD technology is the lack of compactness and portability. In this paper, we present an innovative design of a high resolution optical see-through ET-HMD system based on freeform optical technology. A prototype system is demonstrated, which offers a goggle-like compact form factor, non-obstructive see-through field of view, true high-definition image resolution for the virtual display, and better than 0.5 arc minute of angular resolution for the see-through view. We will demonstrate the application of the technology as an assistive and augmentative communication (AAC) device.

  19. Synthesis and characterization of multi-responsive poly (NIPAm-co-AAc) microgels

    NASA Astrophysics Data System (ADS)

    Haider, Irfan; Siddiq, Mohammad; Mujtaba Shah, Syed; Rehman, Saif ur

    2014-06-01

    Two samples of multi-responsive copolymer microgels, poly(N-isopropylacrylamide-co-acrylic acid) [P(NIPAm-co-AAc)], were synthesized by emulsion polymerization using different amounts of emulsifier. The unreacted monomers and surfactant were removed from the microgels by dialysis. Dynamic Laser Light Scattering (DLS) was used to determine the diffusion coefficient and hydrodynamic radius (Rh) of the microgels at different pH values and temperatures. At pH 7 the microgel showed rapid response to temperature and underwent volume phase transition (VPT) as the temperature was raised. At lower temperature the microgels were in the hydrated or swollen state but beyond 38oC, the size was abruptly decreased. Under different conditions of pH and NaCl concentrations, variations in VPTT values were noticed. By increasing pH the VPTT was increased but the addition of salt had an inverse effect. The weight average molar mass (Mw) and radius of gyration (Rg) were measured by Static Laser Light Scattering (SLS). FTIR spectroscopy was used to confirm the chemical structures of microgels

  20. Pulverizing aeration as a method of lakes restoration

    NASA Astrophysics Data System (ADS)

    Kaczorowska, E.; Podsiadłowski, S.

    2012-04-01

    The principal threat to lakes of the temperate zone is posed by factors accelerating their eutrophication and causing marked deoxygenation of the deeper layers of water, mainly the hypo- and metalimnion. Among their effects are frequent phytoplankton blooms, including those of blue-green algae, and general deterioration of water quality also affecting the abundance and health status of fish. The chief concern is a disturbed proportion between the amount of complex chemical compounds, especially organic, and the oxygen content of lake waters. Natural processes of water oxygenation are not too intensive, because they are practically limited to the epilimnion layer, connected as they are with the activity of aquatic plants of the littoral and sublittoral zone (which tends to disappear in contaminated lakes) and wind energy (the effect of waving). In summer conditions, with a relatively great chemical activity of bottom deposits, the intensity of those processes is usually inadequate. Hence, in 1995 a research was launched in the Institute of Agricultural Engineering of the Agricultural University in Poznań on an integrated lake restoration technology whose core was a self-powered aerator capable of oxygenating also the bottom layers of water (the hypolimnion) of deep lakes. The aerator uses energy obtained from a Savonius rotor mainly to diffuse gases: to release hydrogen sulphide, which usually saturates the hypolimnion water completely, and then to saturate this water with oxygen. Even early studies showed the constructed device to be highly efficient in improving oxygen conditions in the bottom zone. They also made it clear that it should be equipped with an autonomous system designed to inactivate phosphorus, one of the principal factors determining the rate of lake degradation. In 2003 the first wind-driven pulverising aerator equipped with such a system was installed in Town Lake in Chodzież. The aim of this work is to present the principles of operation of a

  1. What We Write about When We Write About AAC: The Past 30 Years of Research and Future Directions.

    PubMed

    McNaughton, David; Light, Janice

    2015-01-01

    For the past 30 years, the Augmentative and Alternative Communication (AAC) journal has both documented and instigated change in the field of AAC. We reviewed the papers published in the AAC journal from 1985-2014 in order to identify trends in research and publication activities. Intervention research made up the largest proportion of the four types of research (i.e., intervention, descriptive, experimental, and instrument and measurement development) reported in the journal. Intervention research has most commonly focused on the individual with complex communication needs, and most frequently on younger individuals (aged 17 and younger) with developmental disabilities. While much has been learned in the past 30 years, there continues to be a need for high quality research in a large number of areas. There is a special need for reports of interventions with older individuals with complex communication needs as a result of acquired disabilities, and for information on effective interventions for the communication partners of persons with complex communication needs. PMID:26490318

  2. The Potential Influence of “Stimulus Overselectivity” in AAC: Information from Eye-tracking and Behavioral Studies of Attention

    PubMed Central

    Dube, William V.; Wilkinson, Krista M.

    2014-01-01

    This paper examines the phenomenon of “stimulus overselectivity” or “overselective attention” as it may impact AAC training and use in individuals with intellectual disabilities. Stimulus overselectivity is defined as an atypical limitation in the number of stimuli or stimulus features within an image that are attended to and subsequently learned. Within AAC, the term “stimulus” could refer to symbols or line drawings on speech generating devices, drawings or pictures on low-technology systems, and/or the elements within visual scene displays. In this context, overselective attention may result in unusual or uneven error patterns such as confusion between two symbols that share a single feature or difficulties with transitioning between different types of hardware. We review some of the ways that overselective attention has been studied behaviorally. We then examine how eye tracking technology allows a glimpse into some of the behavioral characteristics of overselective attention. We describe an intervention approach, differential observing responses, that may reduce or eliminate overselectivity, and we consider this type of intervention as it relates to issues of relevance for AAC. PMID:24773053

  3. Electrokenitic Corrosion Treatment of Concrete

    NASA Technical Reports Server (NTRS)

    Cardenas, Henry E (Inventor)

    2015-01-01

    A method and apparatus for strengthening cementitious concrete by placing a nanoparticle carrier liquid in contact with a first surface of a concrete section and inducing a current across the concrete section at sufficient magnitude and for sufficient time that nanoparticles in the nanoparticle carrier liquid migrate through a significant depth of the concrete section.

  4. Corrosion-resistant sulfur concretes

    NASA Astrophysics Data System (ADS)

    McBee, W. C.; Sullivan, T. A.; Jong, B. W.

    1983-04-01

    Sulfur concretes have been developed by the Bureau of Mines as construction materials with physical and mechanical properties that suit them for use in acid and salt corrosive environments where conventional concretes fail. Mixture design methods were established for preparing sulfur concretes using different types of aggregates and recently developed mixed-modified sulfur cements. Bench-scale testing of the sulfur concretes has shown their potential value. Corrosion resistance, strength, and durability of sulfur concrete are superior to those of conventional materials. Field in situ evaluation tests of the sulfur concretes as replacement for conventional concrete materials are in progress in corrosive areas of 24 commercial chemical, fertilizer, and metallurgical plants.

  5. Precast concrete pavements

    NASA Astrophysics Data System (ADS)

    Rollings, R. S.; Chou, Y. T.

    1981-11-01

    This report reviewed published literature on precast concrete pavements and found that precast concrete pavements have had some limited application in airfields, roads, and storage areas. This review of past experience and an analytical study of precast slabs concluded that existing design and construction techniques can be adapted for use with precast concrete pavements, but more work is needed to develop effective and easily constructed load transfer designs for slab joints. Precast concrete does not offer any advantage for conventional pavements due to its high cost and surface roughness, but it may find applications for special problems such as construction in adverse weather, subgrade settlement, temporary pavements that need to be relocated, and military operations.

  6. Strengthening lightweight concrete

    NASA Technical Reports Server (NTRS)

    Auskern, A.

    1972-01-01

    Polymer absorption by lightweight concretes to improve bonding between cement and aggregate and to increase strength of cement is discussed. Compressive strength of treated cement is compared with strength of untreated product. Process for producing polymers is described.

  7. Shear Resistance between Concrete-Concrete Surfaces

    NASA Astrophysics Data System (ADS)

    Kovačovic, Marek

    2013-12-01

    The application of precast beams and cast-in-situ structural members cast at different times has been typical of bridges and buildings for many years. A load-bearing frame consists of a set of prestressed precast beams supported by columns and diaphragms joined with an additionally cast slab deck. This article is focused on the theoretical and experimental analyses of the shear resistance at an interface. The first part of the paper deals with the state-of-art knowledge of the composite behaviour of concrete-concrete structures and a comparison of the numerical methods introduced in the relevant standards. In the experimental part, a set of specimens with different interface treatments was tested until failure in order to predict the composite behaviour of coupled beams. The experimental part was compared to the numerical analysis performed by means of FEM basis nonlinear software.

  8. Final Report: Retrofit Aeration System (RAS) for Francis Turbine

    SciTech Connect

    Alan Sullivan; DOE Project Officer Keith Bennett

    2006-08-01

    Osage Plant and Bagnell Dam impounds the Osage River forming the Lake of the Ozarks in Missouri. Since it is nearly 100 feet deep, the lake stratifies during the summer months causing low DO water to be discharged into the Osage river below the dam. To supplement DO, the turbines are vented during the low DO season. AmerenUE is continually researching new methods of DO enhancement. New turbines, manufactured by American Hydro Corporation, were installed in Units 3 & 5 during the spring of 2002. Additional vent capacity and new nosecones were included in the new turbine design. The retrofit aeration system is an attempt to further enhance the DO in the tailrace by installation of additional venting capability on Unit 6 (not upgraded with new turbine) and refining design on special nosecones which will be mounted on both Unit 3 (upgraded turbine) and Unit 6. Baseline DO testing for Units 3 & 6 was conducted mid August, 2002. This data wascompared to further tests planned for the summer of 2003 and 2004 after installation of the retrofit aeration system.

  9. Feasibility of biological aerated filters (BAFs) for treating landfill leachate.

    PubMed

    Stephenson, T; Pollard, S J T; Cartmell, E

    2004-03-01

    Ammonia can be removed from landfill leachate using aerobic biological treatment processes. The biological aerated filter (BAF) combines biological treatment and subsequent biomass separation in one reactor providing a small footprint alternative to conventional systems. Leachate from an operational landfill was found to be aerobically treatable using the OECD recommended Modified Zahn-Wellens test. This leachate was used as feed to a pilot-scale BAF at influent chemical oxygen demand (COD) and ammoniacal-nitrogen concentrations of 765 mg l(-1) and 568 mg l(-1) respectively. During an initial period of stable operation without pH control, 33 %w/w of influent ammonia was removed. The reactor pH was 9.2 with little conversion to total oxidized nitrogen (< 45 mg l(-1)), this removal was accounted for primarily by air stripping. In a second period of stable operation, the reactor pH was reduced to pH 7.2 and ammonia removal increased to 97 %w/w with a concomitant increase in effluent nitrite concentration to an average of 524 mg l(-1). Biological aerated filters (BAFs) can be used to nitrify landfill leachates though onward denitrification of nitrite-nitrogen and COD polishing is required to reach typical discharge consent standards.

  10. Galvanic corrosion of nitinol under deaerated and aerated conditions.

    PubMed

    Pound, Bruce G

    2016-10-01

    Various studies have examined the corrosion rate of nitinol generally under deaerated conditions. Likewise, galvanic corrosion studies have typically involved deaerated solutions. This work addressed the effect of galvanic coupling on the corrosion current of electropolished nitinol in phosphate buffered saline and 0.9% sodium chloride under dearated and aerated conditions for times up to 24 h. Tests were performed on nitinol alone and coupled with MP35N in both the mechanically polished and passivated conditions. Aeration and galvanic coupling were found to have relatively little effect, indicating that the corrosion current is controlled by the anodic reaction. The current can be attributed entirely to Ni(2+) dissolution, which appears to be governed by solid-state mass transport of Ni(2+) through the passive oxide film. Because corrosion of EP nitinol is controlled by the anodic reaction, contact between EP nitinol and MP35N or other biomedical Co-Cr alloys is unlikely to result in significant galvanic effects in vivo. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1322-1327, 2016.

  11. The use of bottle caps as submerged aerated filter medium.

    PubMed

    Damasceno de Oliveira, Laurence; Motlagh, Amir Mohaghegh; Goel, Ramesh; de Souza Missagia, Beatriz; Alves de Abreu Filho, Benício; Lautenschlager, Sandro Rogério

    2014-01-01

    In this study, a submerged aerated filter (SAF) using bottle caps as a support medium was evaluated. The system was fed with effluent from an upflow anaerobic sludge blanket system at ETE 2-South wastewater treatment plant, under different volumetric organic load rates (VOLRs). The population of a particular nitrifying microbial community was assessed by fluorescent in situ hybridization with specific oligonucleotide probes. The system showed an average removal of chemical oxygen demand (COD) equal to 76% for VOLRs between 2.6 and 13.6 kg COD m(-3)_media.day(-1). The process of nitrification in conjunction with the removal of organic matter was observed from applying VOLRs lower than 5.5 kg COD m(-3)_media.day(-1) resulting in 78% conversion of NH4(+)-N. As the applied organic load was reduced, an increase in the nitrifying bacteria population was observed compared with total 4'-6-diamidino-2-phenylindole (DAPI) stained cells. Generally, SAF using bottle caps as a biological aerated filter medium treating wastewater from an anaerobic system showed promising removal of chemical oxygen demand (COD) and conversion of NH4(+)-N. PMID:24718345

  12. Performance of "Waterless Concrete"

    NASA Technical Reports Server (NTRS)

    Toutanji, H. A.; Grugel, R. N.

    2009-01-01

    Waterless concrete consists of molten elementary sulfur and aggregate. The aggregates in a lunar environment will be lunar rocks and soil. Sulfur is present on the Moon in Troilite soil (FeS) and, by oxidation of the soil, iron and sulfur can be produced. Sulfur concrete specimens were cycled between liquid nitrogen (approx.]91 C) and room temperature (^21 C) to simulate exposure to a lunar environment. Cycled and control specimens were subsequently tested in compression at room temperatures (^21 C) and ^-101 C. Test results showed that due to temperature cycling, the compressive strength of cycled specimens was 20% of those non-cycled. This reduction in strength can be attributed to the large differences in thermal coefficients of expansion of the materials constituting the concrete which promoted cracking. Similar sulfur concrete mixtures were strengthened with short and long glass fibres. The lunar regolith simulant was melted in a 25 cc Pt- Rh crucible in a Sybron Thermoline high temperature MoSi2 furnace at melting temperatures of 1450 to 1600 C for times of 30 min to i hour. Glass fibres and small rods were pulled from the melt. The glass fibres were used to reinforce sulfur concrete plated to improve the flexural strength of the sulfur concrete. Beams strengthened with glass fibres showed to exhibit an increase in the flexural strength by as much as 45%.

  13. Aerated Shewanella oneidensis in Continuously-fed Bioelectrochemical Systems for Power and Hydrogen Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We studied the effects of aeration of Shewanella oneidensis on potentiostatic current production, iron(III) reduction, hydrogen production in a microbial electrolysis cell, and electric power generation in a microbial fuel cell. The potentiostatic performance of aerated S. oneidensis was considerab...

  14. Bench scale studies of the soil aeration process for bioremediation of petroleum hydrocarbons

    SciTech Connect

    Hinchee, R.E.; Arthur, M.

    1991-12-31

    An alternative to traditional hydrocarbon bioremediation is to pump air through unsaturated soils to create aerobic conditions and induce biodegradation. This study examines the effects of moisture and nutrient augmentation on biodegradation of petroleum hydrocarbons in aerated soils. Findings indicate that forced aeration, coupled with additions of nutrients and moisture, stimulate hydrocarbon-degrading microorganisms and present a feasible approach to bioremediation management.

  15. Surfactant effects on alpha factors in full-scale wastewater aeration systems.

    PubMed

    Rosso, D; Larson, L E; Stenstrom, M K

    2006-01-01

    Aeration is an essential process in the majority of wastewater treatment processes, and accounts for the largest fraction of plant energy costs. Aeration systems can achieve wastewater oxygenation by shearing the surface (surface aerators) or releasing bubbles at the bottom of the tank (coarse- or fine-bubble aerators). Surfactants accumulate on gas-liquid interfaces and reduce mass transfer rates. This reduction in general is larger for fine-bubble aerators. This study was conducted to evaluate mass transfer effects on the characterization and specification of aeration systems in clean and process water conditions. Tests at different interfacial turbulence regimes were analysed, showing higher gas transfer depression for lower turbulence regimes. Higher turbulence regimes can offset contamination effects, at the expense of operating efficiency. This phenomenon is characteristic of surface aerators and coarse bubble diffusers and is here discussed. The results explain the variability of alpha factors measured at small scale, due to uncontrolled energy density. Results are also reported in dimensionless empirical correlations that describe mass transfer as a function of physiochemical and geometrical characteristics of the aeration process. PMID:17165457

  16. Hydraulic characterization and optimization of total nitrogen removal in an aerated vertical subsurface flow treatment wetland.

    PubMed

    Boog, Johannes; Nivala, Jaime; Aubron, Thomas; Wallace, Scott; van Afferden, Manfred; Müller, Roland Arno

    2014-06-01

    In this study, a side-by-side comparison of two pilot-scale vertical subsurface flow constructed wetlands (6.2 m(2)×0.85 m, q(i)=95 L/m(2) d, τ(n)=3.5 d) handling primary treated domestic sewage was conducted. One system (VA-i) was set to intermittent aeration while the other was aerated continuously (VAp-c). Intermittent aeration was provided to VA-i in an 8 h on/4 h off pattern. The intermittently aerated wetland, VA-i, was observed to have 70% less nitrate nitrogen mass outflow than the continuously aerated wetland, VAp-c. Intermittent aeration was shown to increase treatment performance for TN while saving 33% of running energy cost for aeration. Parallel tracer experiments in the two wetlands showed hydraulic characteristics similar to one Continuously Stirred Tank Reactor (CSTR). Intermittent aeration did not significantly affect the hydraulic functioning of the system. Hydraulic efficiencies were 78% for VAp-c and 76% for VA-i.

  17. Experimental investigations of aeration efficiency in high-head gated circular conduits.

    PubMed

    Cihat Tuna, M; Ozkan, Fahri; Baylar, Ahmet

    2014-01-01

    The primary purpose of water aeration is to increase the oxygen saturation of the water. This can be achieved by using hydraulic structures because of substantial air bubble entrainment at these structures. Closed conduit aeration is a particular instance of this. While there has been a great deal of research on air-demand ratio within closed conduit, very little research has specifically addressed aeration efficiency of closed conduit. In the present work an experimental study was conducted to investigate the aeration efficiency of high-head gated circular conduits. Results showed that high-head gated circular conduits were effective for oxygen transfer. The effects of Froude number and ratio of the water cross-sectional flow area to the conduit cross-sectional area on aeration efficiency were particularly significant, whereas the effect of conduit length was only moderate. Further, a design formula for the aeration efficiency was presented relating the aeration efficiency to ratio of water cross-sectional flow area to conduit cross-sectional area and Froude number. The obtained results will be useful in future modeling processes and aid the practicing engineer in predicting aeration efficiency for design purposes.

  18. [Impacts of different aeration modes on nutrients conservation during swine manure composting with magnesium salt addition].

    PubMed

    Yang, Yu; Wei, Yuan-Song; Liu, Jun-Xin

    2009-04-15

    Experiments were carried out to investigate the effect of two aeration modes on nutrients conservation in the thermophilic stage of swine manure composting with adding magnesium chloride. These results indicated that in the end of thermophilic stage of composting, the ammonia nitrogen losses of the piles with the intermittent aeration and with continuous aeration, were 23.56 g and 56.98 g, respectively, which means the loss of ammonia nitrogen of swine composting by the intermittent aeration was just 41.35% of that by the continuous aeration. Such loss of ammonia nitrogen resulted in 9.8% higher of the total kjeldahl nitrogen (TKN) concentration in the pile with the intermittent aeration than that with the continuous aeration. No significant difference occurred between two piles in orthophosphate, sequential extraction phosphorus and the total phosphorus (TP). However, in the pile with intermittent aeration, the percentage of the easily dissolved phosphorous forms such as H2O-P and NaHCO3-P was increased from 27.6% of TP to 66.5%, and the other pile from 27.6% to 64.9%. The TP concentrations in both piles were 17.2 g/kg in the end of thermophilic composting stage. The mixed crystals containing magnesium and phosphorus were formed in both piles of swine composting.

  19. Evaluation of re-aeration equations for river Ghataprabha, Karnataka, India and development of refined equation.

    PubMed

    Kalburgi, P B; Jha, R; Ojha, C S P; Deshannavar, U B

    2015-01-01

    Stream re-aeration is an extremely important component to enhance the self-purification capacity of streams. To estimate the dissolved oxygen (DO) present in the river, estimation of re-aeration coefficient is mandatory. Normally, the re-aeration coefficient is expressed as a function of several stream variables, such as mean stream velocity, shear stress velocity, bed slope, flow depth and Froude number. Many empirical equations have been developed in the last years. In this work, 13 most popular empirical re-aeration equations, used for re-aeration prediction, have been tested for their applicability in Ghataprabha River system, Karnataka, India, at various locations. Extensive field data were collected during the period March 2008 to February 2009 from seven different sites located in the river to observe re-aeration coefficient using mass balance approach. The performance of re-aeration equations have been evaluated using various error estimations, namely, the standard error (SE), mean multiplicative error (MME), normalized mean error (NME) and correlation statistics. The results show that the predictive equation developed by Jha et al. (Refinement of predictive re-aeration equations for a typical Indian river. Hydrological Process. 2001;15(6):1047-1060), for a typical Indian river, yielded the best agreement with the values of SE, MME, NME and correlation coefficient r. Furthermore, a refined predictive equation has been developed for river Ghataprabha using least-squares algorithm that minimizes the error estimates.

  20. Effects of intermittent aeration on pollutants removal in subsurface wastewater infiltration system.

    PubMed

    Pan, Jing; Fei, Hexin; Song, Siyu; Yuan, Fang; Yu, Long

    2015-09-01

    In this study, the pollutant removal performances in two pilot-scale subsurface wastewater infiltration systems (SWISs) with and without intermittent aeration were investigated. Matrix oxidation reduction potential (ORP) results showed that intermittent aeration well developed aerobic conditions in upper matrix and anoxic or anaerobic conditions in the subsequent sections, which resulted in high NH4(+)-N and TN removal. Moreover, intermittent aeration increased removal rates of COD and TP. Microbial populations and enzyme activities analysis proved that intermittent aeration not only obviously boosted the growth and reproduction of bacteria, fungus, actinomyces, nitrifying bacteria and denitrifying bacteria, but also successfully increased nitrate reductase (NR) and nitrite reductase (NIR) in the depth of 80 and 110 cm. The results suggest that the intermittent aeration could be a widespread research and application strategy for achieving the high removal performance in SWISs.

  1. Computational study on microscale behavior of bubble generated by aeration in a plug-flow aeration tank.

    PubMed

    Wang, Huanran; Li, Yanpeng; Zhao, Zhixin

    2009-01-01

    The microscale hydrodynamics of bubbles generated by aeration is directly related to the oxygen transfer efficiency and the overall performance of the activated sludge wastewater treatment process. To gain a deeper insight on the microscale phenomena of dispersed bubble occurring in this process, a three-dimensional direct simulation method is developed to study the effects of the liquid cross-flow on microscale behavior of bubble generation in a plug-flow aeration tank. The numerical simulations are performed using the level set method coupling with the governing equations of a single fluid with variable properties. The governing equations are solved using the finite-volume technique. The simulation results are validated through comparison with experimental observations. The study indicates that the liquid cross-flow has a strong impact on the bubble generation. Compared to that generated under quiescent liquid conditions, the bubble under liquid cross-flow conditions grows downstream along the tilted axis. The bubble generation time tends to decrease noticeably and the bubble at detachment has significantly smaller size. The bubble size and generation time also increase with the increase of gas velocity. The relation of such results to the oxygen transfer efficiency of the wastewater treatment process is also discussed.

  2. Reduction in organic effluent static acute toxicity to fathead minnows by various aeration techniques.

    PubMed

    Belanger, S E; Farris, J L; Cherry, D S

    1988-01-01

    This study compared results of no aeration, intermittent aeration, and constant aeration strategies in determining the static acute (48-h) toxicity of phenolic-based effluents to adult fathead minnows (Pimephales promelas). Toxicity was greatest in no aeration tests followed by intermittent aeration and constant aeration. Two factors were considered responsible for the observed patterns of toxicity. First, in side-by-side tests of no versus intermittent aeration and intermittent versus constant aeration, toxicity reductions were directly attributed to maintenance of dissolved oxygen above 5.0 mg litre(-1) in aerated containers. Secondly, toxicity was reduced when treatment system temperatures were warmest, probably due to increased microbial activity and volatilisation during late spring to early autumn (temperatures > 16 degrees C). Effluent was slightly more toxic on- than off-site, presumably due to degradation of phenolic compounds during transport and set-up at the off-site laboratory (approximately 4.5 h). Gill tissue ultrastructure and histopathology were used to determine the extent of effluent-induced damage and the recovery of minnows to short (6-h) effluent exposures. After a 48-h exposure to the approximate LC(50) level, gill tissue lamellae were characteristically desquamated with epithelium lifting from the basement membrane. Gill tissue was similarly damaged after a 6-h exposure to 100% effluent and had recovered to pre-exposure conditions after 42 h in clean water. Aeration strategies in these studies demonstrated potential air-stripping of volatile compounds, although stress to test organisms from low dissolved oxygen was relieved.

  3. [Optimization and comparison of nitrogen and phosphorus removal by different aeration modes in oxidation ditch].

    PubMed

    Guo, Chang-Zi; Peng, Dang-Cong; Cheng, Xue-Mei; Wang, Dan

    2012-03-01

    The oxidation ditch operation mode was simulated by sequencing batch reactor (SBR) system with alternate stirring and aeration. The nitrogen and phosphorus removal efficiencies were investigated in two different aeration modes: point aeration and step aeration. Experimental results show that oxygen is dissolved more efficiently in point aeration mode with a longer aerobic region in the same air supply capacity, but dissolved oxygen (DO) utilization efficiency for nitrogen and phosphorus removal is high in step aeration mode. Nitrification abilities of the two modes are equal with ammonia-nitrogen (NH4(+) -N) removal efficiency of 96.68% and 97.03%, respectively. Nitrifier activities are 4.65 and 4.66 mg x (g x h)(-1) respectively. When the ratio of anoxic zones and the aerobic zones were 1, the total nitrogen (TN) removal efficiency of point aeration mode in 2, 4 or 7 partitions was respectively 60.14%, 47.93% and 33.7%. The total phosphorus (TP) removal efficiency was respectively 28.96%, 23.75% and 24.31%. The less the partitions, the higher the nitrogen and phosphorus removal efficiencies, but it is in more favor of TN removal. As for step aeration mode with only one partitioning zone, the TN and TP removal efficiencies are respectively 64.21% and 49.09%, which is better than in point aeration mode, but more conducive to the improvement of TP removal efficiency. Under the condition of sufficient nitrification in step aeration mode, the nitrogen and phosphorus removal is better with the increase of anoxic zone. The removal efficiencies of TN and TP respectively rose to 73.94% and 54.18% when the ratio of anoxic zones and the aerobic zones was increased from 1 : 1 to 1. 8 : 1. As the proportion of anoxic zones was enlarged further, nitrification and operation stability were weakened so as to affect the nitrogen and phosphorus removal efficiencies.

  4. 26. Evening view of concrete mixing plant, concrete placement tower, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. Evening view of concrete mixing plant, concrete placement tower, cableway tower, power line and derrick. Photographer unknown, 1927. Source: MWD. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  5. 10. CONCRETE BRIDGE, REINFORCED BEAM TYPE ON CONCRETE, SOUTH CAROLINA ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. CONCRETE BRIDGE, REINFORCED BEAM TYPE ON CONCRETE, SOUTH CAROLINA STATE HIGHWAY DEPARTMENT, COLUMBIA, SOUTH CAROLINA (photocopy of drawing) - Salkehatchie Bridge, State Route No. 64 spanning Salkehatchie River, Barnwell, Barnwell County, SC

  6. Litter aeration and spread of Salmonella in broilers.

    PubMed

    Bodí, Sara González; Garcia, Arantxa Villagra; García, Santiago Vega; Orenga, Clara Marín

    2013-08-01

    Litter quality in the poultry sector is one of the main parameters of health, productivity, and animal welfare. Therefore, innovative management methods have been developed to improve the quality of litter. One of them is litter aeration (LA) by tumbling. However, there is little information related to the effect of this technique on the spreading of pathogens of public health importance such as Salmonella. In this context, the objective of this study was to determine the epidemiology of Salmonella in poultry farms, when serial LA were implemented during the rearing cycle of broilers. For this purpose, an experimental broiler farm with 3 identical rooms was used in the study. Two rooms were assigned to the LA treatment, and the other one served as the control room. Environmental samples were taken in poultry houses after LA in 4 consecutive weeks at the end of the cycle. All samples collected were analyzed according to the standards of the International Organization for Standardization (ISO 6579:2002, Annex D). The results of this study showed that in the control and treated rooms, the percentage of positive samples for Salmonella decreased in the first 3 LA sessions (LA 1, LA 2, and LA 3). However, in the last LA session of rearing (LA 4), the percentage of positive samples increased from 8.2 to 33.2% in the control room instead the treated rooms where the positive samples decreased (P = 0.017). Thus, the aeration of the litter as litter management technique in poultry broiler production does not increase the shedding or the spread of Salmonella throughout broiler houses. In addition, it could be an effective technique to reduce the infective pressure of this bacterium in several areas of the farm or in certain moments of the rearing period with more risk of multiplication and spreading of Salmonella. PMID:23873547

  7. [Effects of substrate-aeration cultivation pattern on tomato growth].

    PubMed

    Zhao, Xu; Li, Tian-Lai; Sun, Zhou-Ping

    2010-01-01

    Aeroponics can increase the fruit yield of tomato plant, but its cost is very high. In this paper, tomato seedlings were planted with three cultures, i. e., whole perlite culture (CK), perlite-aeration culture (T1), and aeroponics (T2), and a comparative study was made on the seedlings growth. Compared with CK, T1 improved the gas environment in root zone significantly, with the CO2 and O2 concentrations in root zone being 0.2 and 1.17 times higher, and increased the plant height and stem diameter after 60 days of transplanting by 5.1% and 8.4%, respectively. The plant net photosynthetic rate of T1 was significantly higher than that of CK, with the maximum value after transplanting 45 days increased by 13%. T1 also increased the root activity and ion absorbing ability significantly, with the root activity after transplanting 45 days being 1.23 times of CK, and the root K, Ca, and Mg contents after transplanting 60 days increased by 31%, 37%, and 27%, respectively. The fruit yield of T1 was 1.16 times of CK. No significant differences in these indices were observed between T1 and T2, and less difference in the fruit soluble sugar and organic acid contents as well as the sugar-acid ratio was found among CK, T1, and T2. It was suggested that perlite-aeration cultivation pattern was an easy and feasible way to markedly improve the fruit yield of tomato plant. PMID:20387426

  8. Litter aeration and spread of Salmonella in broilers.

    PubMed

    Bodí, Sara González; Garcia, Arantxa Villagra; García, Santiago Vega; Orenga, Clara Marín

    2013-08-01

    Litter quality in the poultry sector is one of the main parameters of health, productivity, and animal welfare. Therefore, innovative management methods have been developed to improve the quality of litter. One of them is litter aeration (LA) by tumbling. However, there is little information related to the effect of this technique on the spreading of pathogens of public health importance such as Salmonella. In this context, the objective of this study was to determine the epidemiology of Salmonella in poultry farms, when serial LA were implemented during the rearing cycle of broilers. For this purpose, an experimental broiler farm with 3 identical rooms was used in the study. Two rooms were assigned to the LA treatment, and the other one served as the control room. Environmental samples were taken in poultry houses after LA in 4 consecutive weeks at the end of the cycle. All samples collected were analyzed according to the standards of the International Organization for Standardization (ISO 6579:2002, Annex D). The results of this study showed that in the control and treated rooms, the percentage of positive samples for Salmonella decreased in the first 3 LA sessions (LA 1, LA 2, and LA 3). However, in the last LA session of rearing (LA 4), the percentage of positive samples increased from 8.2 to 33.2% in the control room instead the treated rooms where the positive samples decreased (P = 0.017). Thus, the aeration of the litter as litter management technique in poultry broiler production does not increase the shedding or the spread of Salmonella throughout broiler houses. In addition, it could be an effective technique to reduce the infective pressure of this bacterium in several areas of the farm or in certain moments of the rearing period with more risk of multiplication and spreading of Salmonella.

  9. [Effects of substrate-aeration cultivation pattern on tomato growth].

    PubMed

    Zhao, Xu; Li, Tian-Lai; Sun, Zhou-Ping

    2010-01-01

    Aeroponics can increase the fruit yield of tomato plant, but its cost is very high. In this paper, tomato seedlings were planted with three cultures, i. e., whole perlite culture (CK), perlite-aeration culture (T1), and aeroponics (T2), and a comparative study was made on the seedlings growth. Compared with CK, T1 improved the gas environment in root zone significantly, with the CO2 and O2 concentrations in root zone being 0.2 and 1.17 times higher, and increased the plant height and stem diameter after 60 days of transplanting by 5.1% and 8.4%, respectively. The plant net photosynthetic rate of T1 was significantly higher than that of CK, with the maximum value after transplanting 45 days increased by 13%. T1 also increased the root activity and ion absorbing ability significantly, with the root activity after transplanting 45 days being 1.23 times of CK, and the root K, Ca, and Mg contents after transplanting 60 days increased by 31%, 37%, and 27%, respectively. The fruit yield of T1 was 1.16 times of CK. No significant differences in these indices were observed between T1 and T2, and less difference in the fruit soluble sugar and organic acid contents as well as the sugar-acid ratio was found among CK, T1, and T2. It was suggested that perlite-aeration cultivation pattern was an easy and feasible way to markedly improve the fruit yield of tomato plant.

  10. TH-E-17A-06: Anatomical-Adaptive Compressed Sensing (AACS) Reconstruction for Thoracic 4-Dimensional Cone-Beam CT

    SciTech Connect

    Shieh, C; Kipritidis, J; OBrien, R; Cooper, B; Kuncic, Z; Keall, P

    2014-06-15

    Purpose: The Feldkamp-Davis-Kress (FDK) algorithm currently used for clinical thoracic 4-dimensional (4D) cone-beam CT (CBCT) reconstruction suffers from noise and streaking artifacts due to projection under-sampling. Compressed sensing theory enables reconstruction of under-sampled datasets via total-variation (TV) minimization, but TV-minimization algorithms such as adaptive-steepest-descent-projection-onto-convex-sets (ASD-POCS) often converge slowly and are prone to over-smoothing anatomical details. These disadvantages can be overcome by incorporating general anatomical knowledge via anatomy segmentation. Based on this concept, we have developed an anatomical-adaptive compressed sensing (AACS) algorithm for thoracic 4D-CBCT reconstruction. Methods: AACS is based on the ASD-POCS framework, where each iteration consists of a TV-minimization step and a data fidelity constraint step. Prior to every AACS iteration, four major thoracic anatomical structures - soft tissue, lungs, bony anatomy, and pulmonary details - were segmented from the updated solution image. Based on the segmentation, an anatomical-adaptive weighting was applied to the TV-minimization step, so that TV-minimization was enhanced at noisy/streaky regions and suppressed at anatomical structures of interest. The image quality and convergence speed of AACS was compared to conventional ASD-POCS using an XCAT digital phantom and a patient scan. Results: For the XCAT phantom, the AACS image represented the ground truth better than the ASD-POCS image, giving a higher structural similarity index (0.93 vs. 0.84) and lower absolute difference (1.1*10{sup 4} vs. 1.4*10{sup 4}). For the patient case, while both algorithms resulted in much less noise and streaking than FDK, the AACS image showed considerably better contrast and sharpness of the vessels, tumor, and fiducial marker than the ASD-POCS image. In addition, AACS converged over 50% faster than ASD-POCS in both cases. Conclusions: The proposed AACS

  11. Effects of loading rate and aeration on nitrogen removal and N2O emissions in intermittently aerated sequencing batch reactors treating slaughterhouse wastewater at 11 °C.

    PubMed

    Pan, Min; Hu, Zhenhu; Liu, Rui; Zhan, Xinmin

    2015-04-01

    This study aimed to find optimal operation conditions for nitrogen removal from high strength slaughterhouse wastewater at 11 °C using the intermittently aerated sequencing batch reactors (IASBRs) so as to provide an engineering control strategy for the IASBR technology. Two operational parameters were examined: (1) loading rates and (2) aeration rates. Both the two parameters affected variation of DO concentrations in the IASBR operation cycles. It was found that to achieve efficient nitrogen removal via partial nitrification-denitrification (PND), "DO elbow" point must appear at the end of the last aeration period. There was a correlation between the ammonium oxidizing bacteria (AOB)/nitrite oxidizing bacteria (NOB) ratio and the average DO concentrations in the last aeration periods; when the average DO concentrations in the last aeration periods were lower than 4.86 mg/L, AOB became the dominant nitrifier population, which benefited nitrogen removal via PND. Both the nitrogen loading rate and the aeration rate influenced the population sizes of AOB and NOB. To accomplish efficient nitrogen removal via PND, the optimum aeration rate (A, L air/min) applied can be predicted according to the average organic loading rates based on mathematical equations developed in this study. The research shows that the amount of N2O generation in the aeration period was reduced with increasing the aeration rate; however, the highest N2O generation in the non-aeration period was observed at the optimum aeration rates.

  12. Ammonia-based feedforward and feedback aeration control in activated sludge processes.

    PubMed

    Rieger, Leiv; Jones, Richard M; Dold, Peter L; Bott, Charles B

    2014-01-01

    Aeration control at wastewater treatment plants based on ammonia as the controlled variable is applied for one of two reasons: (1) to reduce aeration costs, or (2) to reduce peaks in effluent ammonia. Aeration limitation has proven to result in significant energy savings, may reduce external carbon addition, and can improve denitrification and biological phosphorus (bio-P) performance. Ammonia control for limiting aeration has been based mainly on feedback control to constrain complete nitrification by maintaining approximately one to two milligrams of nitrogen per liter of ammonia in the effluent. Increased attention has been given to feedforward ammonia control, where aeration control is based on monitoring influent ammonia load. Typically, the intent is to anticipate the impact of sudden load changes, and thereby reduce effluent ammonia peaks. This paper evaluates the fundamentals of ammonia control with a primary focus on feedforward control concepts. A case study discussion is presented that reviews different ammonia-based control approaches. In most instances, feedback control meets the objectives for both aeration limitation and containment of effluent ammonia peaks. Feedforward control, applied specifically for switching aeration on or off in swing zones, can be beneficial when the plant encounters particularly unusual influent disturbances.

  13. Influence of aeration intensity on mature aerobic granules in sequencing batch reactor.

    PubMed

    Gao, Da-Wen; Liu, Lin; Liang, Hong

    2013-05-01

    Aeration intensity is well known as an important factor in the formation of aerobic granules. In this research, two identical lab-scale sequencing batch reactors with aeration intensity of 0.8 (R1) and 0.2 m(3)/h (R2) were operated to investigate the characteristics and kinetics of matured aerobic granules. Results showed that both aeration intensity conditions induced granulation, but they showed different effects on the characteristics of aerobic granules. Compared with the low aeration intensity (R2), the aerobic granules under the higher aeration intensity (R1) had better physical characteristics and settling ability. However, the observed biomass yield (Y obs) in R1 [0.673 kg mixed liquor volatile suspended solids (MLVSS)/kg chemical oxygen demand (COD)] was lower than R2 (0.749 kg MLVSS/kg COD). In addition, the maximum specific COD removal rates (q max) and apparent half rate constant (K) of mature aerobic granular sludge under the two aeration intensities were at a similar level. Therefore, the matured aerobic granule system does not require to be operated in a higher aeration intensity, which will reduce the energy consumption.

  14. Demonstration of membrane aeration panels: City of Geneva Wastewater Treatment Plant. Final report

    SciTech Connect

    1995-01-01

    This report describes the design, construction, and testing of membrane aeration panels at the Marsh Creek wastewater treatment plant (WWTP) in Geneva, NY. The operators at the Geneva plant have undertaken a long-term program to upgrade wastewater treatment processes and lower operating costs. The aging mechanical surface aerators at the Marsh Creek treatment plant were replaced by a state-of-the-art membrane panel system. This fine-bubble diffused air system offers higher oxygen transfer efficiency than surface aerators or other types of fine-bubble diffused-air systems. The project had four objectives: to decrease the amount of electricity used at the plant for aeration; to enable the plant`s existing aeration basins to accommodate higher organic loads and/or nitrify the wastewater should the need arise; to provide an even distribution of dissolved oxygen within the aeration basins to enhance biological wastewater treatment activity; and to provide technical data to assess the performance of the membrane panel system versus other forms of wastewater aeration.

  15. Electrokinetic decontamination of concrete

    SciTech Connect

    Lomasney, H.

    1995-10-01

    The U.S. Department of Energy has assigned a priority to the advancement of technology for decontaminating concrete surfaces which have become contaminated with radionuclides, heavy metals, and toxic organics. This agency is responsible for decontamination and decommissioning of thousands of buildings. Electrokinetic extraction is one of the several innovative technologies which emerged in response to this initiative. This technique utilizes an electropotential gradient and the subsequent electrical transport mechanism to cause the controlled movement of ionics species, whereby the contaminants exit the recesses deep within the concrete. This report discusses the technology and use at the Oak Ridge k-25 plant.

  16. External Guide Sequences Targeting the aac(6′)-Ib mRNA Induce Inhibition of Amikacin Resistance▿

    PubMed Central

    Bistué, Alfonso J. C. Soler; Ha, Hongphuc; Sarno, Renee; Don, Michelle; Zorreguieta, Angeles; Tolmasky, Marcelo E.

    2007-01-01

    The dissemination of AAC(6′)-I-type acetyltransferases have rendered amikacin and other aminoglycosides all but useless in some parts of the world. Antisense technologies could be an alternative to extend the life of these antibiotics. External guide sequences are short antisense oligoribonucleotides that induce RNase P-mediated cleavage of a target RNA by forming a precursor tRNA-like complex. Thirteen-nucleotide external guide sequences complementary to locations within five regions accessible for interaction with antisense oligonucleotides in the mRNA that encodes AAC(6′)-Ib were analyzed. While small variations in the location targeted by different external guide sequences resulted in big changes in efficiency of binding to native aac(6′)-Ib mRNA, most of them induced high levels of RNase P-mediated cleavage in vitro. Recombinant plasmids coding for selected external guide sequences were introduced into Escherichia coli harboring aac(6′)-Ib, and the transformant strains were tested to determine their resistance to amikacin. The two external guide sequences that showed the strongest binding efficiency to the mRNA in vitro, EGSC3 and EGSA2, interfered with expression of the resistance phenotype at different degrees. Growth curve experiments showed that E. coli cells harboring a plasmid coding for EGSC3, the external guide sequence with the highest mRNA binding affinity in vitro, did not grow for at least 300 min in the presence of 15 μg of amikacin/ml. EGSA2, which had a lower mRNA-binding affinity in vitro than EGSC3, inhibited the expression of amikacin resistance at a lesser level; growth of E. coli harboring a plasmid coding for EGSA2, in the presence of 15 μg of amikacin/ml was undetectable for 200 min but reached an optical density at 600 nm of 0.5 after 5 h of incubation. Our results indicate that the use of external guide sequences could be a viable strategy to preserve the efficacy of amikacin. PMID:17387154

  17. The oral core vocabulary of typically developing English-speaking school-aged children: implications for AAC practice.

    PubMed

    Boenisch, Jens; Soto, Gloria

    2015-03-01

    This study analyzes the core vocabulary used by typically developing school-aged English-speaking children in the United States while participating in a variety of school activities. The language of typically developing children, some of whom spoke English as a second language was recorded, transcribed and analyzed to identify the most frequently used words across samples. An inventory of oral core vocabulary of typically developing school-aged children resulted from this analysis. This inventory can be used as a source list for vocabulary selection for school-aged children with AAC needs. Implications for vocabulary selection are discussed.

  18. Neural Activity Associated with Visual Search for Line Drawings on AAC Displays: An Exploration of the Use of fMRI.

    PubMed

    Wilkinson, Krista M; Dennis, Nancy A; Webb, Christina E; Therrien, Mari; Stradtman, Megan; Farmer, Jacquelyn; Leach, Raevynn; Warrenfeltz, Megan; Zeuner, Courtney

    2015-01-01

    Visual aided augmentative and alternative communication (AAC) consists of books or technologies that contain visual symbols to supplement spoken language. A common observation concerning some forms of aided AAC is that message preparation can be frustratingly slow. We explored the uses of fMRI to examine the neural correlates of visual search for line drawings on AAC displays in 18 college students under two experimental conditions. Under one condition, the location of the icons remained stable and participants were able to learn the spatial layout of the display. Under the other condition, constant shuffling of the locations of the icons prevented participants from learning the layout, impeding rapid search. Brain activation was contrasted under these conditions. Rapid search in the stable display was associated with greater activation of cortical and subcortical regions associated with memory, motor learning, and dorsal visual pathways compared to the search in the unpredictable display. Rapid search for line drawings on stable AAC displays involves not just the conceptual knowledge of the symbol meaning but also the integration of motor, memory, and visual-spatial knowledge about the display layout. Further research must study individuals who use AAC, as well as the functional effect of interventions that promote knowledge about array layout.

  19. Aeration of the teuftal landfill: Field scale concept and lab scale simulation.

    PubMed

    Ritzkowski, Marco; Walker, Beat; Kuchta, Kerstin; Raga, Roberto; Stegmann, Rainer

    2016-09-01

    Long lasting post-closure care (PCC) is often the major financial burden for operators of municipal solid waste (MSW) landfills. Beside costs for the installation and maintenance of technical equipment and barriers, in particular long term treatment of leachate and landfill gas has to be paid from capital surplus. Estimations based on laboratory experiments project time periods of many decades until leachate quality allows for direct discharge (i.e. no need for further purification). Projections based on leachate samples derived from the last 37years for 35 German landfills confirm these assumption. Moreover, the data illustrate that in particular ammonium nitrogen concentrations are likely to fall below limit values only after a period of 300years. In order to avoid long lasting PCC the operator of Teuftal landfill, located in the Swiss canton Bern, decided to biologically stabilize the landfill by means of a combined in situ aeration and moisturization approach. In December 2014 the aeration started at a landfill section containing approximately 30% of the total landfill volume. From summer 2016 onwards the remaining part of the landfill will be aerated. Landfill aeration through horizontal gas and leachate drains is carried out for the first time in field scale in Europe. The technical concept is described in the paper. Parallel to field scale aeration, investigations for the carbon and nitrogen turnover are carried out by means of both simulated aerated landfills and simulated anaerobic landfills. The results presented in this paper demonstrate that aeration is capable to enhance, both carbon mobilization and discharge via the gas phase. This effect comes along with a significant increase in bio-stabilization of the waste organic fraction, which positively affects the landfill emission behavior in the long run. In terms of leachate pollution reduction it could be demonstrated that the organic load decrease fast and widely independent of the adjusted aeration

  20. Aeration of the teuftal landfill: Field scale concept and lab scale simulation.

    PubMed

    Ritzkowski, Marco; Walker, Beat; Kuchta, Kerstin; Raga, Roberto; Stegmann, Rainer

    2016-09-01

    Long lasting post-closure care (PCC) is often the major financial burden for operators of municipal solid waste (MSW) landfills. Beside costs for the installation and maintenance of technical equipment and barriers, in particular long term treatment of leachate and landfill gas has to be paid from capital surplus. Estimations based on laboratory experiments project time periods of many decades until leachate quality allows for direct discharge (i.e. no need for further purification). Projections based on leachate samples derived from the last 37years for 35 German landfills confirm these assumption. Moreover, the data illustrate that in particular ammonium nitrogen concentrations are likely to fall below limit values only after a period of 300years. In order to avoid long lasting PCC the operator of Teuftal landfill, located in the Swiss canton Bern, decided to biologically stabilize the landfill by means of a combined in situ aeration and moisturization approach. In December 2014 the aeration started at a landfill section containing approximately 30% of the total landfill volume. From summer 2016 onwards the remaining part of the landfill will be aerated. Landfill aeration through horizontal gas and leachate drains is carried out for the first time in field scale in Europe. The technical concept is described in the paper. Parallel to field scale aeration, investigations for the carbon and nitrogen turnover are carried out by means of both simulated aerated landfills and simulated anaerobic landfills. The results presented in this paper demonstrate that aeration is capable to enhance, both carbon mobilization and discharge via the gas phase. This effect comes along with a significant increase in bio-stabilization of the waste organic fraction, which positively affects the landfill emission behavior in the long run. In terms of leachate pollution reduction it could be demonstrated that the organic load decrease fast and widely independent of the adjusted aeration

  1. [Removal nitrogen of integrated vertical-flow constructed wetland under aeration condition].

    PubMed

    Tao, Min; He, Feng; Xu, Dong; Zhou, Qiao-Hong; Liang, Wei; Chen, Shui-Ping; Wu, Zhen-Bin

    2011-03-01

    Oxygen is an important limit factor of nitrogen removal in constructed wetlands, so it is the key point for improving nitrogen removal efficiency of constructed wetlands that the optimization of oxygen distribution within wetlands. Therefore, oxygen status, nitrogen removal and purification mechanism of integrated vertical-flow constructed wetland (IVCW) under aeration condition in summer and winter have been studied. The results showed that both oxygen levels and aerobic zones were increased in the wetland substrates. The area of oxic zone I (expressing with depth) extended from 22 cm, 17 cm to 53 cm, 44 cm, in summer and winter, respectively. The electric potential (Eh) profiling demonstrated that artificial aeration maintained the pattern of sequential oxic-anoxic-oxic (O-A-O) redox zones within the aerated IVCW in winter, while only two oxic-anoxic (O-A) zones were present inside the non-aerated IVCW in the cold season. The decomposition of organic matter and nitrification were obviously enhanced by artificial aeration since the removal efficiency of COD, TN and NH4(+) -N were increased by 12.2%, 6.9% and 15.1% in winter, respectively. There was no significant accumulation of NO3(-) -N in the effluent with an aeration cycle of 8 h on and 16 h off in this experiment. Moreover, we found that oxic zone I was the main region of pollutants removal in IVCW system, and artificial aeration mainly acted to enhance the purification capacity of this oxic zone in the aerated IVCW. These results suggest that aeration is important for optimization and application of IVCW system.

  2. Aeration remediation of a polluted waterway increases near-surface coarse and culturable microbial aerosols.

    PubMed

    Dueker, M Elias; O'Mullan, Gregory D

    2014-04-15

    Aeration remediation is currently used in polluted urban waterways to increase oxygen levels in the water column. Recent studies have provided increasing evidence that the bursting of bubbles at water surfaces introduced by aeration, or other surface disturbances, can transfer viable bacteria to the air. In heavily sewage-polluted waterways these water-originated bacterial aerosols may pose as a health risk to recreators in small boats or residents inhabiting the shoreline. Nonetheless, few studies have explored aerosols above active aeration remediation projects in waterways or investigated how bacterial aerosols change with vertical distance from aeration activities. This study, conducted at the Newtown Creek superfund site in Brooklyn, NY, USA, measured coarse aerosol particles and culturable bacteria in near-surface air above waters undergoing aeration remediation. Regardless of aeration operation culturable bacterial fallout was greater near-surface (0.6m above water) than previously-reported measurements made at 2.5m. Molecular analysis of the 16S rRNA gene sequences from isolated bacteria demonstrates that water and air shared a large number of bacterial genera and that the genera present in the near-surface aerosols (0.6m) contained water-associated Vibrio and Caulobacter, which were not present at 2.5m, despite the smaller sequence library size from the near-surface. Also, the near-surface microbial assemblage had significantly greater association with sequences detected previously in aquatic environments compared to the 2.5m library. We found compelling evidence that aeration activity contributed to this vertical gradient in bacterial aerosol concentrations and identity. Similar to results from 2.5m, concentrations of near-surface respirable coarse aerosols (<10 um) increased significantly when aeration was occurring. Culturable bacterial aerosol fallout was also greater near-surface when the aerator was on compared to simultaneous measurements made at 2

  3. Enhanced long-term organics and nitrogen removal and associated microbial community in intermittently aerated subsurface flow constructed wetlands.

    PubMed

    Fan, Jinlin; Zhang, Jian; Guo, Wenshan; Liang, Shuang; Wu, Haiming

    2016-08-01

    The long-term enhanced removal efficiency of organics and nitrogen in subsurface flow constructed wetlands (SSF CWs) with and without intermittent aeration for decentralized domestic wastewater was evaluated, and the function of intermittent aeration on microbial community was also investigated in this study. The high and long-term 95.6% COD, 96.1% NH4(+)-N and 85.8% TN removal efficiencies were achieved in experimental intermittently aerated SSF CW compared with non-aerated SSF CW. Aerated SSF CWs also exhibited the excellent removal performance when comparatively comparing with other strategies and techniques applied in CWs. In addition, fluorescence in situ hybridization (FISH) analysis revealed that associated microbial abundance significantly increased owing to intermittent aeration. These results indicated intermittent aeration CWs might be an effective and sustainable strategy for wastewater treatment in rural areas, but require further full-scale investigation in future.

  4. Improving microalgal growth with reduced diameters of aeration bubbles and enhanced mass transfer of solution in an oscillating flow field.

    PubMed

    Yang, Zongbo; Cheng, Jun; Lin, Richen; Zhou, Junhu; Cen, Kefa

    2016-07-01

    A novel oscillating gas aerator combined with an oscillating baffle was proposed to generate smaller aeration bubbles and enhance solution mass transfer, which can improve microalgal growth in a raceway pond. A high-speed photography system (HSP) was used to measure bubble diameter and generation time, and online precise dissolved oxygen probes and pH probes were used to measure mass-transfer coefficient and mixing time. Bubble diameter and generation time decreased with decreased aeration gas rate, decreased orifice diameter, and increased water velocity in the oscillating gas aerator. The optimized oscillating gas aerator decreased bubble diameter and generation time by 25% and 58%, respectively, compared with a horizontal tubular gas aerator. Using an oscillating gas aerator and an oscillating baffle in a raceway pond increased the solution mass-transfer coefficient by 15% and decreased mixing time by 32%; consequently, microalgal biomass yield increased by 19%. PMID:27035474

  5. Improving microalgal growth with reduced diameters of aeration bubbles and enhanced mass transfer of solution in an oscillating flow field.

    PubMed

    Yang, Zongbo; Cheng, Jun; Lin, Richen; Zhou, Junhu; Cen, Kefa

    2016-07-01

    A novel oscillating gas aerator combined with an oscillating baffle was proposed to generate smaller aeration bubbles and enhance solution mass transfer, which can improve microalgal growth in a raceway pond. A high-speed photography system (HSP) was used to measure bubble diameter and generation time, and online precise dissolved oxygen probes and pH probes were used to measure mass-transfer coefficient and mixing time. Bubble diameter and generation time decreased with decreased aeration gas rate, decreased orifice diameter, and increased water velocity in the oscillating gas aerator. The optimized oscillating gas aerator decreased bubble diameter and generation time by 25% and 58%, respectively, compared with a horizontal tubular gas aerator. Using an oscillating gas aerator and an oscillating baffle in a raceway pond increased the solution mass-transfer coefficient by 15% and decreased mixing time by 32%; consequently, microalgal biomass yield increased by 19%.

  6. Heidrun concrete TLP: Update

    SciTech Connect

    Munkejord, T.

    1995-10-01

    This paper gives a summary of the Heidrun substructure including tethers and foundations. The focus will although be on the concrete substructure. The Heidrun Field is located in 345 m water depth in the northern part of the Haltenbanken area, approximately 100N miles from the west coast of mid-Norway. The field is developed by means of a concrete Tension Leg Platform (TLP) by Conoco Norway Inc. The TLP will be moored by 16 steel tethers, arranged in groups of four per corner, which secure the substructure (hull) to the concrete foundations. A general view of the TLP is shown. The Heidrun TLP will be the northern most located platform in the North Sea when installed at Haltenbanken in 1995. Norwegian Contractors a.s (NC) is undertaking the Engineering, Procurement, Construction and Installation (EPCI) contract for the Heidrun TLP substructure. This comprises the complete delivery of the hull with two module support beams (MSB), including all mechanical outfitting. Furthermore, NC will perform all marine operations related to the substructure. For the concrete foundations NC has performed the detailed engineering work and has been responsible for the two to field and installation of the foundations.

  7. High temperature polymer concrete

    DOEpatents

    Fontana, J.J.; Reams, W.

    1984-05-29

    This invention is concerned with a polymer concrete composition, which is a two-component composition useful with many bases including metal. Component A, the aggregate composition, is broadly composed of silica, silica flour, portland cement, and acrylamide, whereas Component B, which is primarily vinyl and acrylyl reactive monomers, is a liquid system.

  8. Electroosmotic decontamination of concrete

    SciTech Connect

    Bostick, W.D.; Bush, S.A.; Marsh, G.C.; Henson, H.M.; Box, W.D.; Morgan, I.L.

    1993-03-01

    A method is described for the electroosmotic decontamination of concrete surfaces, in which an electrical field is used to induce migration of ionic contaminants from porous concrete into an electrolyte solution that may be disposed of as a low-level liquid radioactive waste (LLRW); alternately, the contaminants from the solution can be sorbed onto anion exchange media in order to prevent contaminant buildup in the solution and to minimize the amount of LLRW generated. We have confirmed the removal of uranium (and infer the removal of {sup 99}Tc) from previously contaminated concrete surfaces. In a typical experimental configuration, a stainless steel mesh is placed in an electrolyte solution contained within a diked cell to serve as the negative electrode (cathode) and contaminant collection medium, respectively, and an existing metal penetration (e.g., piping, conduit, or rebar reinforcement within the concrete surface) serves as the positive electrode (anode) to complete the cell. Typically we have achieved 70 to >90% reductions in surface activity by applying <400 V and <1 A for 1--3 h (energy consumption of 0.4--12 kWh/ft{sup 2}).

  9. Bile acids reduce the apoptosis-inducing effects of sodium butyrate on human colon adenoma (AA/C1) cells: implications for colon carcinogenesis.

    PubMed

    McMillan, L; Butcher, S; Wallis, Y; Neoptolemos, J P; Lord, J M

    2000-06-24

    Butyrate is produced in the colon by fermentation of dietary fibre and induces apoptosis in colon adenoma and cancer cell lines, which may contribute to the protective effect of a high fibre diet against colorectal cancer (CRC). However, butyrate is present in the colon together with unconjugated bile acids, which are tumour promoters in the colon. We show here that bile acids deoxycholate (DCA) and chenodeoxycholate (CDCA), at levels present in the colon, gave a modest increase in cell proliferation and decreased spontaneous apoptosis in AA/C1 adenoma cells. Bile acids significantly inhibited the induction of apoptosis by butyrate in AA/C1 cells. However, the survival-inducing effects of bile acids on AA/C1 cells could be overcome by increasing the concentration of sodium butyrate. These results suggest that dysregulation of apoptosis in colonic epithelial cells by dietary factors is a key factor in the pathophysiology of CRC.

  10. Comparing First Graders' Attitudes and Preferences Toward a Peer Using an iPad(®)-Based Speech-Generating Device and a Non-Electronic AAC System.

    PubMed

    Hyppa-Martin, Jolene; Collins, Dana; Chen, Mo; Amundson, Casey; Timinski, Kelli; Mizuko, Mark

    2016-06-01

    This study compared first graders' attitudes toward a peer who used an iPad(®)-based speech-generating device (SGD) versus a non-electronic AAC system, as well as preferences regarding the systems. In all, 115 first graders were randomly assigned to view a video of a peer using either the SGD or the non-electronic system. Participants then completed the Assessment of Attitudes Toward Augmentative and Alternative Communication (AATAAC) and answered preference questions about the systems. Results showed that attitudes toward the peer did not vary significantly as a function of the type of AAC system the peer used. Girls tended to have more positive attitudes than boys toward the peer who used AAC. A majority of participants preferred the SGD for their peer's and for their own use.

  11. Simultaneous natural speech and AAC interventions for children with childhood apraxia of speech: lessons from a speech-language pathologist focus group.

    PubMed

    Oommen, Elizabeth R; McCarthy, John W

    2015-03-01

    In childhood apraxia of speech (CAS), children exhibit varying levels of speech intelligibility depending on the nature of errors in articulation and prosody. Augmentative and alternative communication (AAC) strategies are beneficial, and commonly adopted with children with CAS. This study focused on the decision-making process and strategies adopted by speech-language pathologists (SLPs) when simultaneously implementing interventions that focused on natural speech and AAC. Eight SLPs, with significant clinical experience in CAS and AAC interventions, participated in an online focus group. Thematic analysis revealed eight themes: key decision-making factors; treatment history and rationale; benefits; challenges; therapy strategies and activities; collaboration with team members; recommendations; and other comments. Results are discussed along with clinical implications and directions for future research.

  12. Human isolates of apramycin-resistant Escherichia coli which contain the genes for the AAC(3)IV enzyme.

    PubMed Central

    Hunter, J. E.; Hart, C. A.; Shelley, J. C.; Walton, J. R.; Bennett, M.

    1993-01-01

    Gentamicin-resistant Escherichia coli isolated at different periods from patients in two hospitals were tested for resistance to the aminoglycoside antibiotic apramycin. Twenty-four of 93 (26%) gentamicin-resistant isolates collected from the Royal Liverpool Hospital between 1981 and 1990 were resistant to apramycin. Thirteen isolates were highly resistant to apramycin (minimal inhibitory concentration (MIC) > or = 1024 micrograms/ml), were also resistant to gentamicin, netilmicin and tobramycin, and hybridized with a DNA probe derived from the aminoglycoside acetyltransferase (3)IV (AAC(3)IV) gene. The proportion of gentamicin-resistant isolates which had high level resistance to apramycin increased from 7% in 1981-5 to 24% in 1986-90. Twelve gentamicin-resistant E. coli from Guy's and St Thomas's Hospital isolated between 1977 and 1980 were also tested for resistance to apramycin. For five of these isolates the MICs of apramycin was 32-256 micrograms/ml. None was shown to have a conjugative plasmid carrying resistance to apramycin and only one hybridized with the DNA probe for the AAC(3)IV enzyme. PMID:8472768

  13. Structure of the bifunctional aminoglycoside-resistance enzyme AAC(6')-Ie-APH(2'')-Ia revealed by crystallographic and small-angle X-ray scattering analysis.

    PubMed

    Smith, Clyde A; Toth, Marta; Weiss, Thomas M; Frase, Hilary; Vakulenko, Sergei B

    2014-10-01

    Broad-spectrum resistance to aminoglycoside antibiotics in clinically important Gram-positive staphylococcal and enterococcal pathogens is primarily conferred by the bifunctional enzyme AAC(6')-Ie-APH(2'')-Ia. This enzyme possesses an N-terminal coenzyme A-dependent acetyltransferase domain [AAC(6')-Ie] and a C-terminal GTP-dependent phosphotransferase domain [APH(2'')-Ia], and together they produce resistance to almost all known aminoglycosides in clinical use. Despite considerable effort over the last two or more decades, structural details of AAC(6')-Ie-APH(2'')-Ia have remained elusive. In a recent breakthrough, the structure of the isolated C-terminal APH(2'')-Ia enzyme was determined as the binary Mg2GDP complex. Here, the high-resolution structure of the N-terminal AAC(6')-Ie enzyme is reported as a ternary kanamycin/coenzyme A abortive complex. The structure of the full-length bifunctional enzyme has subsequently been elucidated based upon small-angle X-ray scattering data using the two crystallographic models. The AAC(6')-Ie enzyme is joined to APH(2'')-Ia by a short, predominantly rigid linker at the N-terminal end of a long α-helix. This α-helix is in turn intrinsically associated with the N-terminus of APH(2'')-Ia. This structural arrangement supports earlier observations that the presence of the intact α-helix is essential to the activity of both functionalities of the full-length AAC(6')-Ie-APH(2'')-Ia enzyme.

  14. Micro-aeration for hydrogen sulfide removal from biogas

    NASA Astrophysics Data System (ADS)

    Duangmanee, Thanapong

    The presence of sulfur compounds (e.g. protein, sulfate, thiosulfate, sulfite, etc.) in the feed stream generates highly corrosive and odorous hydrogen sulfide during anaerobic digestion. The high sulfide level in the biogas stream is not only poisonous to many novel metal catalysts employed in thermo-catalytic processes but also reduces the quality of methane to produce renewable energy. This study used an innovative, low-maintenance, low-cost biological sulfide removal technology to remove sulfides simultaneously from both gas and liquid phase. ORP (Oxidation-Reduction-Potential) was used as the controlling parameter to precisely regulate air injection to the sulfide oxidizing unit (SOU). The microaeration technique provided just enough oxygen to partially oxidize sulfides to elemental sulfur without inhibiting methanogenesis. The SOU was equipped with a diffuser at the bottom for the dispersion of sulfide-laden biogas and injected air throughout the column. The SOU can be operated as a standalone unit or coupled with an anaerobic digester to simultaneously remove sulfide from the biogas and effluent. The integrated system was capable of reducing hydrogen sulfide in biogas from 2,450 to less than 2 ppmV with minimal sulfate production at the highest available sulfide loading rate of 0.24 kg/m3-day. More than 98% of sulfide removed was recovered as elemental sulfur. However, the standalone SOU was able to operate at high hydrogen sulfide loading of 1.46 kg/m 3-day at inlet sulfide concentration of 3000 ppmV and reduce the off-gas hydrogen sulfide concentrations to less than 10 ppmV. The experiment also revealed that the ORP controlled aeration was sensitive enough to prevent oxygen overdosing (dampening effect) during unexpected surges of aeration. Using generalized linear regression, a model predicting output H2S concentration based on input H2S concentrations, SOU medium heights, and biogas flow rates, was derived. With 95% confidence, output H2S concentration

  15. Improving microalgal growth with small bubbles in a raceway pond with swing gas aerators.

    PubMed

    Yang, Zongbo; Cheng, Jun; Liu, Jianzhong; Zhou, Junhu; Cen, Kefa

    2016-09-01

    A novel swing gas aerator was developed to generate small bubbles for improving the mass transfer coefficient and microalgal growth rate in a raceway pond. A high-speed photography system (HSP) was used to measure the bubble diameter and generation time, and online precise dissolved oxygen probes and pH probes were used to measure the mass transfer coefficient and mixing time. Bubble generation time and diameter decreased by 21% and 9%, respectively, when rubber gas aerators were swung in the microalgae solution. When water pump power and gas aeration rate increased in a raceway pond with swing gas aerators and oscillating baffles (SGAOB), bubble generation time and diameter decreased but solution velocity and mass transfer coefficient increased. The mass transfer coefficient increased by 25% and the solution velocity increased by 11% when SGAOB was used, and the microalgal biomass yield increased by 18%.

  16. Survival of Salmonella enterica in Aerated and Nonaerated Wastewaters from Dairy Lagoons

    PubMed Central

    Ravva, Subbarao V.; Sarreal, Chester Z.

    2014-01-01

    Salmonella is the most commonly identified foodborne pathogen in produce, meat and poultry. Cattle are known reservoirs of Salmonella and the pathogen excreted in feces ends up in manure flush lagoons. Salmonella enterica survival was monitored in wastewater from on-site holding lagoons equipped or not with circulating aerators at two dairies. All strains had poor survival rates and none proliferated in waters from aerated or settling lagoons. Populations of all three Salmonella serovars declined rapidly with decimal reduction times (D) of <2 days in aerated microcosms prepared from lagoon equipped with circulators. Populations of Salmonella decreased significantly in aerated microcosms (D = 4.2 d) compared to nonaerated waters (D = 7.4 d) and in summer (D = 3.4 d) compared to winter (D = 9.0 d). We propose holding the wastewater for sufficient decimal reduction cycles in lagoons to yield pathogen-free nutrient-rich water for crop irrigations and fertilization. PMID:25358096

  17. Improved design and optimization of aeration control for WWTPs by dynamic simulation.

    PubMed

    Alex, J; To, T Binh; Hartwig, P

    2002-01-01

    This paper introduces a model library based on the simulation environment MATLAB/SIMULINK which allows the simulation of the aeration system of an wastewater treatment plant (WWTP). The model library presented covers all parts of an aeration system starting with the compressor set over the common air rail, flow resistances through pipes, controllable valves, aeration membranes and ending last not least with the controllers involved. The main objective of the development of the simulation system is the design, test and the support of the installation of more predictable and efficient control concepts for the aeration system in WWTPs. An example is given to demonstrate the application of the simulation system and to promote a control scheme with a flexible reference value for the pressure at the common air rail based on a most open valve (MOV) concept.

  18. Survival of Salmonella enterica in aerated and nonaerated wastewaters from dairy lagoons.

    PubMed

    Ravva, Subbarao V; Sarreal, Chester Z

    2014-11-01

    Salmonella is the most commonly identified foodborne pathogen in produce, meat and poultry. Cattle are known reservoirs of Salmonella and the pathogen excreted in feces ends up in manure flush lagoons. Salmonella enterica survival was monitored in wastewater from on-site holding lagoons equipped or not with circulating aerators at two dairies. All strains had poor survival rates and none proliferated in waters from aerated or settling lagoons. Populations of all three Salmonella serovars declined rapidly with decimal reduction times (D) of <2 days in aerated microcosms prepared from lagoon equipped with circulators. Populations of Salmonella decreased significantly in aerated microcosms (D = 4.2 d) compared to nonaerated waters (D = 7.4 d) and in summer (D = 3.4 d) compared to winter (D = 9.0 d). We propose holding the wastewater for sufficient decimal reduction cycles in lagoons to yield pathogen-free nutrient-rich water for crop irrigations and fertilization. PMID:25358096

  19. Survival of Salmonella enterica in aerated and nonaerated wastewaters from dairy lagoons.

    PubMed

    Ravva, Subbarao V; Sarreal, Chester Z

    2014-10-29

    Salmonella is the most commonly identified foodborne pathogen in produce, meat and poultry. Cattle are known reservoirs of Salmonella and the pathogen excreted in feces ends up in manure flush lagoons. Salmonella enterica survival was monitored in wastewater from on-site holding lagoons equipped or not with circulating aerators at two dairies. All strains had poor survival rates and none proliferated in waters from aerated or settling lagoons. Populations of all three Salmonella serovars declined rapidly with decimal reduction times (D) of <2 days in aerated microcosms prepared from lagoon equipped with circulators. Populations of Salmonella decreased significantly in aerated microcosms (D = 4.2 d) compared to nonaerated waters (D = 7.4 d) and in summer (D = 3.4 d) compared to winter (D = 9.0 d). We propose holding the wastewater for sufficient decimal reduction cycles in lagoons to yield pathogen-free nutrient-rich water for crop irrigations and fertilization.

  20. Improving microalgal growth with small bubbles in a raceway pond with swing gas aerators.

    PubMed

    Yang, Zongbo; Cheng, Jun; Liu, Jianzhong; Zhou, Junhu; Cen, Kefa

    2016-09-01

    A novel swing gas aerator was developed to generate small bubbles for improving the mass transfer coefficient and microalgal growth rate in a raceway pond. A high-speed photography system (HSP) was used to measure the bubble diameter and generation time, and online precise dissolved oxygen probes and pH probes were used to measure the mass transfer coefficient and mixing time. Bubble generation time and diameter decreased by 21% and 9%, respectively, when rubber gas aerators were swung in the microalgae solution. When water pump power and gas aeration rate increased in a raceway pond with swing gas aerators and oscillating baffles (SGAOB), bubble generation time and diameter decreased but solution velocity and mass transfer coefficient increased. The mass transfer coefficient increased by 25% and the solution velocity increased by 11% when SGAOB was used, and the microalgal biomass yield increased by 18%. PMID:27243604

  1. Application of membrane tubing aeration and perfluorocarbon To improve oxygen delivery to hairy root cultures

    PubMed

    Kanokwaree; Doran

    1998-05-01

    Growth and atropine production by Atropa belladonna hairy roots were studied in bioreactor cultures using porous polypropylene membrane tubing as a supplementary aeration device and with FC-43 perfluorocarbon emulsion added to the medium. Both these treatments were applied to improve oxygen transfer to the roots. Membrane tubing aeration allowed direct delivery of oxygen within the root clump, thus overcoming mass transfer resistances associated with poor intraclump penetration of liquid convective currents. Combined air sparging and membrane tubing aeration in a gas-driven bioreactor supported biomass levels 32-65% higher than sparging only of air or oxygen-enriched air at the same total gas flow rate. The optimal air flow rate ratio between the sparger and membrane tubing giving the maximum final biomass concentration was 0.2:0.4 L min-1. Intraclump dissolved oxygen tensions at high biomass densities were generally greater using air delivered by combined sparger-membrane tubing aeration than with sparging only of air or oxygen-enriched air. Specific atropine levels were not significantly affected by membrane tubing aeration. Indicators of anaerobic metabolism, such as lactic acid, ethanol, and ADH activity levels, were not significantly different in sparged and membrane-aerated systems; A. belladonna hairy roots also did not produce aerenchyma in response to oxygen limitations. Addition of perfluorocarbon emulsion to Murashige and Skoog medium in sparged stirred tank bioreactors did not improve growth, even when the emulsion was continuously recycled for re-aeration in an external vessel. Perfluorocarbons are associated with enhancement of gas-liquid oxygen transfer, so their ineffectiveness in this work most likely reflects the dominance of liquid-solid transfer resistances in hairy root cultures. The results of this investigation highlight the importance of developing new approaches for site-directed aeration of hairy root cultures, targeting oxygen delivery

  2. Modelisation of the contribution of sediments in the treatment process case of aerated lagoons.

    PubMed

    Jupsin, H; Vasel, J L

    2007-01-01

    In aerated lagoons and even more in stabilization ponds the specific power (W/m3) is not high enough to maintain all the suspended solids in suspension. Some part of the suspended solids (including biomass) settles directly into the reactor and not in the final settling pond. The gradual accumulation of those sediments on the pond bottom affects performance by reducing the pond volume and shortening the Hydraulic Residence Time. However, the role played by these deposits is not restricted to such a physical effect. Far from being inert sediments they are also an important oxygen sink that must be taken into account when designing aerator power and oxygen supply, for example. On the other hand, under aerobic conditions, the upper layer of sediments may contribute to the treatment as a biofilm compartment in the reactor. In aerated lagoon systems another process contributes to the interaction of deposits and the liquid phase: the operating (often sequencing) of aerators may induce a drastic resuspension of deposits. In a 3,000 m3 aerated lagoon we evaluated that 3 tons of deposits were resuspended when aerators were started. Due to those processes we consider that a mathematical model of an aerated lagoon or of a stabilization pond has to take into account the contribution (positive and negative aspects) of deposits in the process. In this paper we propose a model for sediments including production but also biological processes. Simulations of the aerated lagoon with or without the "sediment compartment" demonstrate the effect and the importance of this compartment on the process. Of course a similar approach could be used for facultative or even maturation ponds. The next step would be to include anaerobic activities in the bottom layer. PMID:17591192

  3. Nitrate-removal activity of a biofilm attached to a perlite carrier under continuous aeration conditions.

    PubMed

    Yamashita, Takahiro; Yokoyama, Hiroshi; Kanafusa, Sumiyo; Ogino, Akifumi; Ishida, Mitsuyoshi; Osada, Takashi; Tanaka, Yasuo

    2011-01-01

    The nitrate-removal activity of a biofilm attached to a perlite carrier from an aerobic bioreactor used for treating dairy farm wastewater was examined by batch experiments under continuous aeration conditions. Despite aeration, the biofilm removed nitrate at a rate of 114.4 mg-N/kg-perlite/h from wastewater containing cow milk and manure. In a clone library analysis of the biofilm, bacteria showing high similarity to the denitrifying bacteria Thauera spp. were detected.

  4. Photosynthetic aeration in biological wastewater treatment using immobilized microalgae-bacteria symbiosis.

    PubMed

    Praveen, Prashant; Loh, Kai-Chee

    2015-12-01

    Chlorella vulgaris encapsulated in alginate beads were added into a bioreactor treating synthetic wastewater using Pseudomonas putida. A symbiotic CO2/O2 gas exchange was established between the two microorganisms for photosynthetic aeration of wastewater. During batch operation, glucose removal efficiency in the bioreactor improved from 50% in 12 h without aeration to 100% in 6 h, when the bioreactor was aerated photosynthetically. During continuous operation, the bioreactor was operated at a low hydraulic retention time of 3.3 h at feed concentrations of 250 and 500 mg/L glucose. The removal efficiency at 500 mg/L increased from 73% without aeration to 100% in the presence of immobilized microalgae. The initial microalgae concentration was critical to achieve adequate aeration, and the removal rate increased with increasing microalgae concentration. The highest removal rate of 142 mg/L-h glucose was achieved at an initial microalgae concentration of 190 mg/L. Quantification of microalgae growth in the alginate beads indicated an exponential growth during symbiosis, indicating that the bioreactor performance was limited by oxygen production rates. Under symbiotic conditions, the chlorophyll content of the immobilized microalgae increased by more than 30%. These results indicate that immobilized microalgae in symbiosis with heterotrophic bacteria are promising in wastewater aeration. PMID:26266755

  5. Ecophysiology of wetland plant roots: A modelling comparison of aeration in relation to species distribution

    USGS Publications Warehouse

    Sorrell, B.K.; Mendelssohn, I.A.; McKee, K.L.; Woods, R.A.

    2000-01-01

    This study examined the potential for inter-specific differences in root aeration to determine wetland plant distribution in nature. We compared aeration in species that differ in the type of sediment and depth of water they colonize. Differences in root anatomy, structure and physiology were applied to aeration models that predicted the maximum possible aerobic lengths and development of anoxic zones in primary adventitious roots. Differences in anatomy and metabolism that provided higher axial fluxes of oxygen allowed deeper root growth in species that favour more reducing sediments and deeper water. Modelling identified factors that affected growth in anoxic soils through their effects on aeration. These included lateral root formation, which occurred at the expense of extension of the primary root because of the additional respiratory demand they imposed, reducing oxygen fluxes to the tip and stele, and the development of stelar anoxia. However, changes in sediment oxygen demand had little detectable effect on aeration in the primary roots due to their low wall permeability and high surface impedance, but appeared to reduce internal oxygen availability by accelerating loss from laterals. The development of pressurized convective gas flow in shoots and rhizomes was also found to be important in assisting root aeration, as it maintained higher basal oxygen concentrations at the rhizome-root junctions in species growing into deep water. (C) 2000 Annals of Botany Company.

  6. Improving hydrolysis acidification by limited aeration in the pretreatment of petrochemical wastewater.

    PubMed

    Wu, Changyong; Zhou, Yuexi; Wang, Peichao; Guo, Shujun

    2015-10-01

    Petrochemical wastewater was pretreated by hydrolysis acidification to improve the biodegradation and treatability on limited aeration conditions. The results showed limited aeration with DO from 0.2 to 0.3mg/L (average ORP was -210 mV) was the best condition. The BOD5/COD of influent was 0.23, and it increased to 0.43 on this condition. Limited aeration can obviously reduce the reduction of SO4(2-), reducing the generation of toxic gas H2S, and almost no H2S can be detected in the off-gas. The sulfate reducing bacteria (SRB) diversity and abundance on limited aeration condition was obviously inhibited. Limited aeration condition was benefit for the removal of benzene ring organics, such as benzene, toluene, ethylbenzene and xylenes (BTEX), improving the toxicity and treatability of the wastewater. Based on the experiment results, an anaerobic hydrolysis acidification tank (100,000 m(3)) has been transformed into limited aeration hydrolysis acidification tank and it runs well.

  7. Photosynthetic aeration in biological wastewater treatment using immobilized microalgae-bacteria symbiosis.

    PubMed

    Praveen, Prashant; Loh, Kai-Chee

    2015-12-01

    Chlorella vulgaris encapsulated in alginate beads were added into a bioreactor treating synthetic wastewater using Pseudomonas putida. A symbiotic CO2/O2 gas exchange was established between the two microorganisms for photosynthetic aeration of wastewater. During batch operation, glucose removal efficiency in the bioreactor improved from 50% in 12 h without aeration to 100% in 6 h, when the bioreactor was aerated photosynthetically. During continuous operation, the bioreactor was operated at a low hydraulic retention time of 3.3 h at feed concentrations of 250 and 500 mg/L glucose. The removal efficiency at 500 mg/L increased from 73% without aeration to 100% in the presence of immobilized microalgae. The initial microalgae concentration was critical to achieve adequate aeration, and the removal rate increased with increasing microalgae concentration. The highest removal rate of 142 mg/L-h glucose was achieved at an initial microalgae concentration of 190 mg/L. Quantification of microalgae growth in the alginate beads indicated an exponential growth during symbiosis, indicating that the bioreactor performance was limited by oxygen production rates. Under symbiotic conditions, the chlorophyll content of the immobilized microalgae increased by more than 30%. These results indicate that immobilized microalgae in symbiosis with heterotrophic bacteria are promising in wastewater aeration.

  8. Aeration effect on Spirulina platensis growth and γ-Linolenic acid production.

    PubMed

    Ronda, Srinivasa Reddy; Bokka, Chandra Sekhar; Ketineni, Chandrika; Rijal, Binod; Allu, Prasada Rao

    2012-01-01

    The influence of aeration on algal growth and gamma-linolenic acid (GLA) production in a bubble column photobioreactor was investigated. Studies were performed in a 20-L reactor at different aeration rates (0.2- 2.5 vvm). Static, continuous, and periodic operation of air resulted in 41.9%, 88.4%, and 108% air saturation of dissolved oxygen, for which the corresponding values of GLA were 2.3, 6.5, and 7.5 mg·g(-1) dry cell weight, respectively. An increase in the aeration rate from 0.2 to 2.5 vvm enhanced both the specific growth rate and GLA content under periodic sparging in the bicarbonate medium. With a 6-fold increase in the aeration rate, the GLA content of the alga increased by 69.64% (5.6-9.5 mg· g(-1) dry cell weight). In addition, the total fatty acid (TFA) content in dry biomass increased from 2.22% to 4.41%, whereas the algae maintained a constant GLA to TFA ratio within the aeration rate tested. The dependence of GLA production on the aeration rate was explained by interrelating the GLA production rate with the specific growth rate using the Luedeking and Piret mixed growth model.

  9. Laboratory study of nitrification, denitrification and anammox processes in membrane bioreactors considering periodic aeration.

    PubMed

    Abbassi, Rouzbeh; Yadav, Asheesh Kumar; Huang, Shan; Jaffé, Peter R

    2014-09-01

    The possibility of using membrane bioreactors (MBRs) in simultaneous nitrification-anammox-denitrification (SNAD) by considering periodic aeration cycles was investigated. Two separate reactors were operated to investigate the effect of different anammox biomass in the presence of nitrifying and denitrifying biomass on the final nitrogen removal efficiency. The results illustrated that the reactor with higher anammox biomass was more robust to oxygen cycling. Around 98% Total Nitrogen (TN) and 83% Total Organic Carbon (TOC) removal efficiencies were observed by applying one hour aeration over a four-hour cycle. Decreasing the aeration time to 30, 15, and 2 min during a four-hour cycle affected the final TN removal efficiencies. However, the effect of decreasing aeration on the TN removal efficiencies in the reactor with higher anammox biomass was much lower compared to the regular reactor. The nitrous oxide (N2O) emission was a function of aeration as well, and was lower in the reactor with higher anammox biomass. The results of q-PCR analysis confirmed the simultaneous co-existence of nitrifiers, anammox, and denitrifiers in both of the reactors. To simulate the TN removal in these reactors as a function of the aeration time, a new model, based on first order reaction kinetics for both denitrification and anammox was developed and yielded a good agreement with the experimental observations.

  10. Improving arachidonic acid fermentation by Mortierella alpina through multistage temperature and aeration rate control in bioreactor.

    PubMed

    Gao, Min-Jie; Wang, Cheng; Zheng, Zhi-Yong; Zhu, Li; Zhan, Xiao-Bei; Lin, Chi-Chung

    2016-05-18

    Effective production of arachidonic acid (ARA) using Mortierella alpina was conducted in a 30-L airlift bioreactor. Varying the aeration rate and temperature significantly influenced cell morphology, cell growth, and ARA production, while the optimal aeration rate and temperature for cell growth and product formation were quite different. As a result, a two-stage aeration rate control strategy was constructed based on monitoring of cell morphology and ARA production under various aeration rate control levels (0.6-1.8 vvm). Using this strategy, ARA yield reached 4.7 g/L, an increase of 38.2% compared with the control (constant aeration rate control at 1.0 vvm). Dynamic temperature-control strategy was implemented based on the fermentation performance at various temperatures (13-28°C), with ARA level in total cellular lipid increased by 37.1% comparing to a constant-temperature control (25°C). On that basis, the combinatorial fermentation strategy of two-stage aeration rate control and dynamic temperature control was applied and ARA production achieved the highest level of 5.8 g/L.

  11. [Oxygen transfer efficiency of four kinds substrates applied in artificial aeration vertical-flow wetland].

    PubMed

    Pan, Ji-Zheng; Li, Wen-Chao; Ke, Fan; Wang, Lei; Li, Xue-Juan

    2009-02-15

    In subsurface flow constructed wetlands, artificial aeration plays an important role in enhancing the ability of pollutant removal. Oxygenation capacity of four substrates, limestone, vesuvianite, 500 grade ceramisite and high-strength ceramisite, are tested under three kinds of gas volume [0.19, 0.38, 0.76 m3 x (m2 x h)(-1)] in artificial aeration vertical-flow wetland. When the gas volume is 0.19 m3 x (m2 x h)(-1), the results demonstrate that the oxygen utilization of 500 grade ceramisite and high-strength ceramisite are highest as 14.39% and 14.21%, and the oxygen utilization of limestone and vesuvianite are 11.68% and 13.11% respectively. With the increase of aeration intensity, oxygen transfer efficiency parameter KLa rises accordingly. However, the oxygen utilization of vesuvianite and two other kinds of ceramisite decreases with the increase of aeration intensity. The oxygen utilization of vesuvianite, 500 grad ceramisite and high-strength ceramisite are lower as 7.67%, 10.46% and 10.77% respectively when the aeration intensity is 0.76 m3 x (m2 x h)(-1). On the contrary, the oxygen utilization of limestone get its maximum value of 14.04% as the aeration intensity is 0.38 m3 x (m2 x h)(-1).

  12. An aeration control strategy for oxidation ditch processes based on online oxygen requirement estimation.

    PubMed

    Zhan, J X; Ikehata, M; Mayuzumi, M; Koizumi, E; Kawaguchi, Y; Hashimoto, T

    2013-01-01

    A feedforward-feedback aeration control strategy based on online oxygen requirements (OR) estimation is proposed for oxidation ditch (OD) processes, and it is further developed for intermittent aeration OD processes, which are the most popular type in Japan. For calculating OR, concentrations of influent biochemical oxygen demand (BOD) and total Kjeldahl nitrogen (TKN) are estimated online by the measurement of suspended solids (SS) and sometimes TKN is estimated by NH4-N. Mixed liquor suspended solids (MLSS) and temperature are used to estimate the required oxygen for endogenous respiration. A straightforward parameter named aeration coefficient, Ka, is introduced as the only parameter that can be tuned automatically by feedback control or manually by the operators. Simulation with an activated sludge model was performed in comparison to fixed-interval aeration and satisfying result of OR control strategy was obtained. The OR control strategy has been implemented at seven full-scale OD plants and improvements in nitrogen removal are obtained in all these plants. Among them, the results obtained in Yumoto wastewater treatment plant were presented, in which continuous aeration was applied previously. After implementing intermittent OR control, the total nitrogen concentration was reduced from more than 5 mg/L to under 2 mg/L, and the electricity consumption was reduced by 61.2% for aeration or 21.5% for the whole plant. PMID:23823542

  13. Evaluation of aeration energy saving in two modified activated sludge processes.

    PubMed

    Lee, Ingyu; Lim, Honglae; Jung, Byunghun; Colosimo, Mark F; Kim, Hyunook

    2015-12-01

    A variety of modified activated sludge processes are widely used in wastewater treatment plants (WWTPs) for removing organics and nutrients (N and P). Since energy consumption in aeration basin accounts for the major part of the overall energy usage in WWTPs, efforts have been made to find ways to reduce aeration energy. In this study, two modified activated sludge processes in a pilot scale designed for nutrient removal were evaluated for the extent of energy saving: (1) ABA(2) process - adjusting air on/off period (i.e., with a temporal change); and (2) MB-A(2)O process - changing volume ratio of aerobic tank to anoxic tank (i.e., with a spatial change). For the 1st process, the air on/off period was fixed at 60min/45min with aerobic fraction being 0.57, while for the 2nd process, the aerobic/anoxic volume ratio was reduced from 0.58 to 0.42. The results demonstrate that the effluent COD, TN, NH4(+) and TP concentrations are acceptable while reduced aeration time/volume certainly saves significant energy consumption. To the best of our knowledge, this is 1st attempt to reduce the aeration period or aeration volume to save the aeration energy in these two modified activated sludge processes. The implication of these observations is further discussed.

  14. Generating CO{sub 2}-credits through landfill in situ aeration

    SciTech Connect

    Ritzkowski, M.; Stegmann, R.

    2010-04-15

    Landfills are some of the major anthropogenic sources of methane emissions worldwide. The installation and operation of gas extraction systems for many landfills in Europe and the US, often including technical installations for energy recovery, significantly reduced these emissions during the last decades. Residual landfill gas, however, is still continuously produced after the energy recovery became economically unattractive, thus resulting in ongoing methane emissions for many years. By landfill in situ aeration these methane emissions can be widely avoided both, during the aeration process as well as in the subsequent aftercare period. Based on model calculations and online monitoring data the amount of avoided CO{sub 2-eq}. can be determined. For an in situ aerated landfill in northern Germany, acting as a case study, 83-95% (depending on the kind and quality of top cover) of the greenhouse gas emission potential could be reduced under strictly controlled conditions. Recently the United Nations Framework Convention on Climate Change (UNFCCC) has approved a new methodology on the 'Avoidance of landfill gas emissions by in situ aeration of landfills' (). Based on this methodology landfill aeration projects might be considered for generation of Certified Emission Reductions (CERs) in the course of CDM projects. This paper contributes towards an evaluation of the potential of landfill aeration for methane emissions reduction.

  15. Aeration effect on Spirulina platensis growth and γ-Linolenic acid production

    PubMed Central

    Ronda, Srinivasa Reddy; Bokka, Chandra Sekhar; Ketineni, Chandrika; Rijal, Binod; Allu, Prasada Rao

    2012-01-01

    The influence of aeration on algal growth and gamma-linolenic acid (GLA) production in a bubble column photobioreactor was investigated. Studies were performed in a 20-L reactor at different aeration rates (0.2– 2.5 vvm). Static, continuous, and periodic operation of air resulted in 41.9%, 88.4%, and 108% air saturation of dissolved oxygen, for which the corresponding values of GLA were 2.3, 6.5, and 7.5 mg·g-1 dry cell weight, respectively. An increase in the aeration rate from 0.2 to 2.5 vvm enhanced both the specific growth rate and GLA content under periodic sparging in the bicarbonate medium. With a 6-fold increase in the aeration rate, the GLA content of the alga increased by 69.64% (5.6–9.5 mg· g-1 dry cell weight). In addition, the total fatty acid (TFA) content in dry biomass increased from 2.22% to 4.41%, whereas the algae maintained a constant GLA to TFA ratio within the aeration rate tested. The dependence of GLA production on the aeration rate was explained by interrelating the GLA production rate with the specific growth rate using the Luedeking and Piret mixed growth model. PMID:24031799

  16. Nitrogen removal in intermittently aerated biofilm airlift reactor

    SciTech Connect

    Benthum, W.A.J. van; Mathijssen, J.P.M.; Sunde, J.; Loosdrecht, M.C.M. van; Heijnen, J.J.; Garrido, J.M.

    1998-03-01

    Nitrogen compounds like ammonium, nitrite, and nitrate can be found in domestic as well as industrial wastewaters. These compounds can cause many environmental problems in surface waters but can be removed by applying nitrification and denitrification processes. Denitrification was integrated in a nitrifying biofilm airlift suspension reactor by intermittent aeration. A total nitrogen-removal efficiency of 75% was reached at an aerobic ammonia load of 5 kg{sub N}{center_dot}m{sup {minus}3}{center_dot}d{sup {minus}1}. Acetate was added to the reactor during the anoxic periods. The system was operated at sufficiently long anoxic hydraulic retention times to allow suspended growth of denitrifying heterotrophs. However, the heterotrophic biomass did not grow in suspension but grew as protuberances and layers on the nitrifying biofilms. Nitrification and denitrification occurred via nitrite as an intermediate, possibly because denitrifiers outcompeted the nitrite oxidizers. Because of the establishing of the nitrite route, a low average COD/N ratio of 2.6 kg{sub COD}{center_dot}kg{sub N}{sup {minus}1} was obtained. When denitrifying operation with acetate addition was started, initially almost all nitrogen removed was emitted as nitrous oxide. Subsequently, the nitrous oxide emission strongly decreased to almost zero in a period of 30 days, while the nitrogen-removal efficiency was maintained.

  17. Removal of pharmaceuticals in aerated biofilters with manganese feeding.

    PubMed

    Zhang, Yongjun; Zhu, Hong; Szewzyk, Ulrich; Geissen, Sven Uwe

    2015-04-01

    A tertiary treatment step is required in current wastewater treatment plants to remove trace pollutants and thus to prevent their extensive occurrence in the aquatic environment. In this study, natural MnOx ore and natural zeolite were separately used to pack two lab-scale aerated biofilters, which were operated in approximately 1.5 years for the removal of frequently occurring pharmaceuticals, including carbamazepine (CBZ), diclofenac (DFC), and sulfamethoxazole (SMX), out of synthetic and real secondary effluents. Mn(2+) was added in the feeds to promote the growth of iron/manganese oxidizing bacteria which were recently found to be capable of degrading recalcitrant pollutants. An effective removal (80-90%) of DFC and SMX was observed in both biofilters after adaptation while a significant removal of CBZ was not found. Both biofilters also achieved an effective removal of spiked Mn(2+), but a limited removal of carbon and nitrogen contents. Additionally, MnOx biofilter removed 50% of UV254 from real secondary effluent, indicating a high potential on the removal of aromatic compounds.

  18. Concrete lunar base investigation

    NASA Technical Reports Server (NTRS)

    Lin, T. D.; Senseny, Jonathan A.; Arp, Larry D.; Lindbergh, Charles

    1992-01-01

    This paper presents results of structural analyses and a preliminary design of a precast, prestressed concrete lunar base subjected to 1-atm internal pressure. The proposed infrastructure measures 120 ft in diameter and 72 ft in height, providing 33,000 sq ft of work area for scientific and industrial operations. Three loading conditions were considered in the design (1) during construction, (2) under pressurization, and (3) during an air-leak scenario. A floating foundation, capable of rigid body rotation and translation as the lunar soil beneath it yields, was developed to support the infrastructure and to ensure the airtightness of the system. Results reveal that it is feasible to use precast, prestressed concrete for construction of large lunar bases on the Moon.

  19. Concrete lunar base investigation

    NASA Technical Reports Server (NTRS)

    Lin, T. D.; Senseney, Jonathan A.; Arp, Larry Dean; Lindbergh, Charles

    1989-01-01

    This paper presents results of structural analyses and a preliminary design of a precast, prestressed concrete lunar based subjected to one atmosphere internal pressure. The proposed infrastructure measures 120 ft in diameter and 72 ft in height, providing 33,000 sq ft of work area for scientific and industrial operations. Three loading conditions were considered in the design: (1) during construction; (2) under pressurization; and (3) during an air-leak scenario. A floating foundation, capable of rigid body rotation and translation as the lunar soil beneath it yields, was developed to support the infrastructure and to ensure the air-tightness of the system. Results reveal that it is feasible to use precast, prestressed concrete for construction of large lunar bases on the moon.

  20. Concrete containment aging study

    SciTech Connect

    Pachner, J.; Tai, T.M.; Naus, D.

    1994-04-01

    In 1989, IAEA initiated a pilot study on the management of aging of nuclear power plant components. The Phase I and II studies of concrete containment are discussed. With the data base, plant owners will be able to review and enhance their existing programs. IAEA will analyze data provided by participating plants and the report is scheduled to be released by late 1994 (final report release mid-1995).

  1. Laser ablation of concrete.

    SciTech Connect

    Savina, M.

    1998-10-05

    Laser ablation is effective both as an analytical tool and as a means of removing surface coatings. The elemental composition of surfaces can be determined by either mass spectrometry or atomic emission spectroscopy of the atomized effluent. Paint can be removed from aircraft without damage to the underlying aluminum substrate, and environmentally damaged buildings and sculptures can be restored by ablating away deposited grime. A recent application of laser ablation is the removal of radioactive contaminants from the surface and near-surface regions of concrete. We present the results of ablation tests on concrete samples using a high power pulsed Nd:YAG laser with fiber optic beam delivery. The laser-surface interaction was studied on various model systems consisting of Type I Portland cement with varying amounts of either fine silica or sand in an effort to understand the effect of substrate composition on ablation rates and mechanisms. A sample of non-contaminated concrete from a nuclear power plant was also studied. In addition, cement and concrete samples were doped with non-radioactive isotopes of elements representative of cooling waterspills, such as cesium and strontium, and analyzed by laser-resorption mass spectrometry to determine the contamination pathways. These samples were also ablated at high power to determine the efficiency with which surface contaminants are removed and captured. The results show that the neat cement matrix melts and vaporizes when little or no sand or aggregate is present. Surface flows of liquid material are readily apparent on the ablated surface and the captured aerosol takes the form of glassy beads up to a few tens of microns in diameter. The presence of sand and aggregate particles causes the material to disaggregate on ablation, with intact particles on the millimeter size scale leaving the surface. Laser resorption mass spectrometric analysis showed that cesium and potassium have similar chemical environments in the

  2. Chlorine signal attenuation in concrete.

    PubMed

    Naqvi, A A; Maslehuddin, M; ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method.

  3. iCataly-PseAAC: Identification of Enzymes Catalytic Sites Using Sequence Evolution Information with Grey Model GM (2,1).

    PubMed

    Xiao, Xuan; Hui, Meng-Juan; Liu, Zi; Qiu, Wang-Ren

    2015-12-01

    Enzymes play pivotal roles in most of the biological reaction. The catalytic residues of an enzyme are defined as the amino acids which are directly involved in chemical catalysis; the knowledge of these residues is important for understanding enzyme function. Given an enzyme, which residues are the catalytic sites, and which residues are not? This is the first important problem for in-depth understanding the catalytic mechanism and drug development. With the explosive of protein sequences generated during the post-genomic era, it is highly desirable for both basic research and drug design to develop fast and reliable method for identifying the catalytic sites of enzymes according to their sequences. To address this problem, we proposed a new predictor, called iCataly-PseAAC. In the prediction system, the peptide sample was formulated with sequence evolution information via grey system model GM(2,1). It was observed by the rigorous jackknife test and independent dataset test that iCataly-PseAAC was superior to exist predictions though its only use sequence information. As a user-friendly web server, iCataly-PseAAC is freely accessible at http://www.jci-bioinfo.cn/iCataly-PseAAC. A step-by-step guide has been provided on how to use the web server to get the desired results for the convenience of most experimental scientists. PMID:26077845

  4. Eye-Tracking Measures Reveal How Changes in the Design of Aided AAC Displays Influence the Efficiency of Locating Symbols by School-Age Children without Disabilities

    ERIC Educational Resources Information Center

    Wilkinson, Krista M.; O'Neill, Tara; McIlvane, William J.

    2014-01-01

    Purpose: Many individuals with communication impairments use aided augmentative and alternative communication (AAC) systems involving letters, words, or line drawings that rely on the visual modality. It seems reasonable to suggest that display design should incorporate information about how users attend to and process visual information. The…

  5. PMQR genes oqxAB and aac(6′)Ib-cr accelerate the development of fluoroquinolone resistance in Salmonella typhimurium

    PubMed Central

    Wong, Marcus H.; Chan, Edward W.; Liu, Li Z.; Chen, Sheng

    2014-01-01

    Emergence of multidrug-resistant Salmonella typhimurium strains, especially the ACSSuT and nalidixic acid R types, has significantly compromised the effectiveness of current strategies to control Salmonella infections, resulting in increased morbidity and mortality. Clinical S. typhimurium isolates recovered in Hong Kong during the period of 2005–2011 were increasingly resistant to ciprofloxacin (CIP) and antibiotics of the ACSSuT group. Our data revealed that oqxAB and aac(6′)Ib-cr were encoded on plasmids of various sizes and the presence of these two elements together with a single gyrA mutation in S. typhimurium were sufficient to mediate resistance to CIP. Acquisition of the oqxAB and aac(6′)Ib-cr encoding plasmids by S. typhimurium caused a fourfold increase in CIP minimal inhibitory concentration. Furthermore, the presence of oqxAB and aac(6′)Ib-cr in Salmonella dramatically increased the mutation prevention concentration of CIP which may due to mutational changes in the drug target genes. In conclusion, possession of oqxAB and aac(6′)Ib-cr encoding plasmid facilitate the selection of CIP resistant S. typhimurium, thereby causing a remarkable increase of CIP resistance among clinical Salmonella strains in Hong Kong. PMID:25324840

  6. iCataly-PseAAC: Identification of Enzymes Catalytic Sites Using Sequence Evolution Information with Grey Model GM (2,1).

    PubMed

    Xiao, Xuan; Hui, Meng-Juan; Liu, Zi; Qiu, Wang-Ren

    2015-12-01

    Enzymes play pivotal roles in most of the biological reaction. The catalytic residues of an enzyme are defined as the amino acids which are directly involved in chemical catalysis; the knowledge of these residues is important for understanding enzyme function. Given an enzyme, which residues are the catalytic sites, and which residues are not? This is the first important problem for in-depth understanding the catalytic mechanism and drug development. With the explosive of protein sequences generated during the post-genomic era, it is highly desirable for both basic research and drug design to develop fast and reliable method for identifying the catalytic sites of enzymes according to their sequences. To address this problem, we proposed a new predictor, called iCataly-PseAAC. In the prediction system, the peptide sample was formulated with sequence evolution information via grey system model GM(2,1). It was observed by the rigorous jackknife test and independent dataset test that iCataly-PseAAC was superior to exist predictions though its only use sequence information. As a user-friendly web server, iCataly-PseAAC is freely accessible at http://www.jci-bioinfo.cn/iCataly-PseAAC. A step-by-step guide has been provided on how to use the web server to get the desired results for the convenience of most experimental scientists.

  7. Silver-catalysed azide-alkyne cycloaddition (AgAAC): assessing the mechanism by density functional theory calculations

    NASA Astrophysics Data System (ADS)

    Banerji, Biswadip; Chandrasekhar, K.; Killi, Sunil Kumar; Pramanik, Sumit Kumar; Uttam, Pal; Sen, Sudeshna; Maiti, Nakul Chandra

    2016-09-01

    `Click reactions' are the copper catalysed dipolar cycloaddition reaction of azides and alkynes to incorporate nitrogens into a cyclic hydrocarbon scaffold forming a triazole ring. Owing to its efficiency and versatility, this reaction and the products, triazole-containing heterocycles, have immense importance in medicinal chemistry. Copper is the only known catalyst to carry out this reaction, the mechanism of which remains unclear. We report here that the `click reactions' can also be catalysed by silver halides in non-aqueous medium. It constitutes an alternative to the well-known CuAAC click reaction. The yield of the reaction varies on the type of counter ion present in the silver salt. This reaction exhibits significant features, such as high regioselectivity, mild reaction conditions, easy availability of substrates and reasonably good yields. In this communication, the findings of a new catalyst along with the effect of solvent and counter ions will help to decipher the still obscure mechanism of this important reaction.

  8. Optimization of reinforced concrete slabs

    NASA Technical Reports Server (NTRS)

    Ferritto, J. M.

    1979-01-01

    Reinforced concrete cells composed of concrete slabs and used to limit the effects of accidental explosions during hazardous explosives operations are analyzed. An automated design procedure which considers the dynamic nonlinear behavior of the reinforced concrete of arbitrary geometrical and structural configuration subjected to dynamic pressure loading is discussed. The optimum design of the slab is examined using an interior penalty function. The optimization procedure is presented and the results are discussed and compared with finite element analysis.

  9. Reducing aeration energy consumption in a large-scale membrane bioreactor: Process simulation and engineering application.

    PubMed

    Sun, Jianyu; Liang, Peng; Yan, Xiaoxu; Zuo, Kuichang; Xiao, Kang; Xia, Junlin; Qiu, Yong; Wu, Qing; Wu, Shijia; Huang, Xia; Qi, Meng; Wen, Xianghua

    2016-04-15

    Reducing the energy consumption of membrane bioreactors (MBRs) is highly important for their wider application in wastewater treatment engineering. Of particular significance is reducing aeration in aerobic tanks to reduce the overall energy consumption. This study proposed an in situ ammonia-N-based feedback control strategy for aeration in aerobic tanks; this was tested via model simulation and through a large-scale (50,000 m(3)/d) engineering application. A full-scale MBR model was developed based on the activated sludge model (ASM) and was calibrated to the actual MBR. The aeration control strategy took the form of a two-step cascaded proportion-integration (PI) feedback algorithm. Algorithmic parameters were optimized via model simulation. The strategy achieved real-time adjustment of aeration amounts based on feedback from effluent quality (i.e., ammonia-N). The effectiveness of the strategy was evaluated through both the model platform and the full-scale engineering application. In the former, the aeration flow rate was reduced by 15-20%. In the engineering application, the aeration flow rate was reduced by 20%, and overall specific energy consumption correspondingly reduced by 4% to 0.45 kWh/m(3)-effluent, using the present practice of regulating the angle of guide vanes of fixed-frequency blowers. Potential energy savings are expected to be higher for MBRs with variable-frequency blowers. This study indicated that the ammonia-N-based aeration control strategy holds promise for application in full-scale MBRs.

  10. High-sulfate, high-chemical oxygen demand wastewater treatment using aerated methanogenic fluidized beds

    SciTech Connect

    Zitomer, D.H.; Shrout, J.D.

    2000-02-01

    Many industrial wastewaters have both high organic pollution and sulfate (SO{sub 4}{sup {minus}2}) concentrations. Although biological conversion of organics to methane may be an economical chemical oxygen demand (COD) removal option, significant inhibition of methane production results from reduction of SO{sub 4}{sup {minus}2} to hydrogen sulfide (H{sub 2}S), which is inhibitory to methanogenic microorganisms. Therefore, sulfate-containing wastewater is often not amenable to conventional anaerobic treatment. Recently, limited aeration of recycle flow to hybrid and baffled reactors has been used to treat this wastewater and has been shown to reduce aqueous H{sub 2}S concentrations by causing production of uninhibitory sulfur (S{degree}) and thiosulfate (S{sub 2}O{sub 3}{sup {minus}2}) as well as gas stripping volatile H{sub 2}S. In this study, directly aerated methanogenic fluidized bed reactors (FBRs) achieved increased methane production compared to strictly anaerobic FBRs treating high-sulfate wastewater. Oxygen transfer satisfying up to 28% of the COD load resulted in maximum specific oxygen utilization rates of 0.20 mg oxygen/g volatile solids{center{underscore}dot}min, with significant, concomitant methane production. Under typically inhibitory SO{sub 4}{sup {minus}2} loading, higher aeration caused increased effluent SO{sub 4}{sup {minus}2}, increased H{sub 2}S mass in the offgas, and lower reactor H{sub 2}S concentration. As a result, COD removal increased from 25% for a strictly anaerobic FBR to 87% for an aerated FBR. In addition, aerated systems required significantly less alkalinity supplementation to maintain a pH value of 7, ostensibly because of stripping of acidic carbon dioxide. The potential pH increase associated with aeration also shifts sulfide speciation to less toxic disulfide. Direct, limited aeration of methanogenic FBRs is described as a method for increased COD removal when treating high-COD, high-sulfate wastewater.

  11. Arsenic sorption in phosphate-amended soils during flooding and subsequent aeration

    SciTech Connect

    Reynolds, J.G.; Naylor, D.V.; Fendorf, S.E.

    1999-10-01

    Phosphate enhances the mobility of As in well-aerated soils by competing for adsorption sites. Phosphate and As may also coexist in large concentrations in hydric soils, and the influence of P on As in anaerobic systems is largely unknown. To determine the effects of P on As dynamics during a soil flooding and aeration cycle, samples of two soils were amended with Na{sub 2}HAsO{sub 4} and Na{sub 2}HPO, and incubated under a N{sub 2} atmosphere for 41 d, and then reaerated for 7 d. Subsamples were collected intermittently and dissolved As, Fe, Mn, Ca, S, P, and H{sub 3}AsO{sub 3} concentrations were determined. Arsenic speciation in the soil solids was determined after 14 and 41 d of flooding and then after 13 h of aeration by X-ray absorption near edge structure (XANES) spectroscopy. Arsenic sorption was small under anaerobic conditions, and H{sub 2}PO{sub 4}{sup {minus}} additions enhanced As(V) reduction rate in both soils and slightly suppressed As sorption in one soil. Arsenopyrite (FeAsS) was identified in the soil solids. Rapid and simultaneous As sorption and Fe precipitation occurred during the first 0.25 d of aeration, suggesting that As was retained on freshly precipitated Fe (hydr)oxides. Manganese precipitation and concomitant As sorption occurred after 1d of aeration. Arsenopyrite was largely destroyed upon aeration but As(III) persisted. Thus, As is partitioned into the solid phase under both aerobic and anaerobic conditions, although more appreciably under the aerobic conditions of this study, and P has little influence on dissolved As during soil flooding-aeration cycles.

  12. Evaluation of six aerator modules built on venturi air injectors using clean water test.

    PubMed

    Dong, C; Zhu, J; Miller, C F

    2009-01-01

    Six aerator modules constructed using venturi air injectors connected in either series or parallel were evaluated and compared for their oxygen transfer coefficients (OTC), standard oxygen transfer rate (SOTR), and standard oxygenation efficiency (SOE) determined by clean water tests. Modules in series (module a, b, c) included one, two, and three venturi injectors, respectively. The aerator module with two (module d) and three (module e, f) venturi injectors in parallel were used, while module f had less friction and more even flow rate in each line compared with module e. The results showed that the OTC, SOTR, and SOE for the six different module configurations (module a, b, c, d, e, f) were 4.54, 3.79, 3.58, 8.37, 5.93 and 11.87 h(-1); 0.10, 0.09, 0.09, 0.18, 0.15, and 0.31 kgO(2)/h; and 0.07, 0.06, 0.06, 0.12, 0.10, and 0.21 kgO(2)/kWh, respectively. The observations indicate that a 3-fold increase in SOTR and 3.5-fold increase in SOE can be obtained by simply changing the way that venturi air injectors are connected, which suggests that it is possible to improve the aeration efficiency of a venturi type aeration system by innovative aerator module designs. In view of the situation that the venturi aeration systems currently used for swine manure lagoons need significant improvement in their performance in order to match the cost-effective requirement, more research in aerator module development is needed so that effective control of odor from liquid swine manure lagoons can be achieved at an affordable cost. The technology such developed can also be applied to other livestock species. PMID:19717924

  13. Structure of the phosphotransferase domain of the bifunctional aminoglycoside-resistance enzyme AAC(6')-Ie-APH(2'')-Ia.

    PubMed

    Smith, Clyde A; Toth, Marta; Bhattacharya, Monolekha; Frase, Hilary; Vakulenko, Sergei B

    2014-06-01

    The bifunctional acetyltransferase(6')-Ie-phosphotransferase(2'')-Ia [AAC(6')-Ie-APH(2'')-Ia] is the most important aminoglycoside-resistance enzyme in Gram-positive bacteria, conferring resistance to almost all known aminoglycoside antibiotics in clinical use. Owing to its importance, this enzyme has been the focus of intensive research since its isolation in the mid-1980s but, despite much effort, structural details of AAC(6')-Ie-APH(2'')-Ia have remained elusive. The structure of the Mg2GDP complex of the APH(2'')-Ia domain of the bifunctional enzyme has now been determined at 2.3 Å resolution. The structure of APH(2'')-Ia is reminiscent of the structures of other aminoglycoside phosphotransferases, having a two-domain architecture with the nucleotide-binding site located at the junction of the two domains. Unlike the previously characterized APH(2'')-IIa and APH(2'')-IVa enzymes, which are capable of utilizing both ATP and GTP as the phosphate donors, APH(2'')-Ia uses GTP exclusively in the phosphorylation of the aminoglycoside antibiotics, and in this regard closely resembles the GTP-dependent APH(2'')-IIIa enzyme. In APH(2'')-Ia this GTP selectivity is governed by the presence of a `gatekeeper' residue, Tyr100, the side chain of which projects into the active site and effectively blocks access to the adenine-binding template. Mutation of this tyrosine residue to a less bulky phenylalanine provides better access for ATP to the NTP-binding template and converts APH(2'')-Ia into a dual-specificity enzyme.

  14. Ambient iron-mediated aeration (IMA) for water reuse.

    PubMed

    Deng, Yang; Englehardt, James D; Abdul-Aziz, Samer; Bataille, Tristan; Cueto, Josenrique; De Leon, Omar; Wright, Mary E; Gardinali, Piero; Narayanan, Aarthi; Polar, Jose; Tomoyuki, Shibata

    2013-02-01

    Global water shortages caused by rapidly expanding population, escalating water consumption, and dwindling water reserves have rendered water reuse a strategically significant approach to meet current and future water demand. This study is the first to our knowledge to evaluate the technical feasibility of iron-mediated aeration (IMA), an innovative, potentially economical, holistic, oxidizing co-precipitation process operating at room temperature, atmospheric pressure, and neutral pH, for water reuse. In the IMA process, dissolved oxygen (O₂) was continuously activated by zero-valent iron (Fe⁰) to produce reactive oxygen species (ROS) at ambient pH, temperature, and pressure. Concurrently, iron sludge was generated as a result of iron corrosion. Bench-scale tests were conducted to study the performance of IMA for treatment of secondary effluent, natural surface water, and simulated contaminated water. The following removal efficiencies were achieved: 82.2% glyoxylic acid, ~100% formaldehyde as an oxidation product of glyoxylic acid, 94% of Ca²⁺ and associated alkalinity, 44% of chemical oxygen demand (COD), 26% of electrical conductivity (EC), 98% of di-n-butyl phthalate (DBP), 80% of 17β-estradiol (E2), 45% of total nitrogen (TN), 96% of total phosphorus (TP), 99.8% of total Cr, >90% of total Ni, 99% of color, 3.2 log removal of total coliform, and 2.4 log removal of E. Coli. Removal was attributed principally to chemical oxidation, precipitation, co-precipitation, coagulation, adsorption, and air stripping concurrently occurring during the IMA treatment. Results suggest that IMA is a promising treatment technology for water reuse.

  15. Prolong the life of concrete

    SciTech Connect

    Ilaria, J.E.

    1995-07-01

    The most widely used construction materials are concrete and related cement-based products, such as common building block. The excellent reputation of concrete as a durable material of construction has been questioned i modern times. The expanded use of Portland cement concrete, the increase in corrosive environments, and lack of understanding of the composition of concrete all indicate a need for methods to increase life expectancy. Chemical and mechanical factors can shorten service life. Understanding these properties will lead to the proper application of protective coatings.

  16. Microwave NDE for Reinforced Concrete

    NASA Astrophysics Data System (ADS)

    Arunachalam, Kavitha; Melapudi, Vikram R.; Rothwell, Edward J.; Udpa, Lalita; Udpa, Satish S.

    2006-03-01

    Nondestructive assessment of the integrity of civil structures is of paramount importance for ensuring safety. In concrete imaging, radiography, ground penetrating radar and infrared thermography are some of the widely used techniques for health monitoring. Other emerging technologies that are gaining impetus for detecting and locating flaws in steel reinforcement bar include radioactive computed tomography, microwave holography, microwave and acoustic tomography. Of all the emerging techniques, microwave NDT is a promising imaging modality largely due to their ability to penetrate thick concrete structures, contrast between steel rebar and concrete and their non-radioactive nature. This paper investigates the feasibility of a far field microwave NDE technique for reinforced concrete structures.

  17. Enhanced in vitro transdermal delivery of caffeine using a temperature- and pH-sensitive nanogel, poly(NIPAM-co-AAc).

    PubMed

    Abu Samah, Nor H; Heard, Charles M

    2013-09-10

    Temperature- and pH-responsive poly(N-isopropylacrylamide) (polyNIPAM) copolymerised with 5% (w/v) of acrylic acid (AAc), termed as poly(NIPAM-co-AAc) nanogel was investigated as a novel multi-responsive topical drug delivery carrier, using caffeine as a model permeant. The role of a pH modulator (citric acid) on the nanogel system was also studied. The loading was carried out in deionised water at two different temperatures, which were 2-4°C and 25°C (room temperature, RT) over 3 days. The loading of caffeine into the poly(NIPAM-co-AAc) nanogel was found to be significantly higher at 2-4°C than at RT (p=0.0072). As for the control nanogel (polyNIPAM), a similar pattern of loading level can be observed (p=0.0005). This enhanced loading at low temperatures could be attributed to the hydrophilic behaviour of the polyNIPAM network in response to temperatures lower than its lower critical solution temperature (LCST). In vitro diffusion studies across epidermis porcine skin were carried out at 32°C for the saturated solution of caffeine as well as caffeine-loaded poly(NIPAM-co-AAc) and polyNIPAM nanogels. The in vitro permeation data of caffeine-loaded poly(NIPAM-co-AAc) at 2-4°C were shown to enhance the delivery of the loaded caffeine across the epidermis in comparison to the saturated solution of caffeine, by 3.5 orders of magnitude. Additionally, the study demonstrated that the effect of pH modulator on the release of loaded permeant was insignificant.

  18. Multidrug-resistant Pseudomonas aeruginosa strain that caused an outbreak in a neurosurgery ward and its aac(6')-Iae gene cassette encoding a novel aminoglycoside acetyltransferase.

    PubMed

    Sekiguchi, Jun-ichiro; Asagi, Tsukasa; Miyoshi-Akiyama, Tohru; Fujino, Tomoko; Kobayashi, Intetsu; Morita, Koji; Kikuchi, Yoshihiro; Kuratsuji, Tadatoshi; Kirikae, Teruo

    2005-09-01

    We characterized multidrug-resistant Pseudomonas aeruginosa strains isolated from patients involved in an outbreak of catheter-associated urinary tract infections that occurred in a neurosurgery ward of a hospital in Sendai, Japan. Pulsed-field gel electrophoresis of SpeI-, XbaI-, or HpaI-digested genomic DNAs from the isolates revealed that clonal expansion of a P. aeruginosa strain designated IMCJ2.S1 had occurred in the ward. This strain possessed broad-spectrum resistance to aminoglycosides, beta-lactams, fluoroquinolones, tetracyclines, sulfonamides, and chlorhexidine. Strain IMCJ2.S1 showed a level of resistance to some kinds of disinfectants similar to that of a control strain of P. aeruginosa, ATCC 27853. IMCJ2.S1 contained a novel class 1 integron, In113, in the chromosome but not on a plasmid. In113 contains an array of three gene cassettes of bla(IMP-1), a novel aminoglycoside resistance gene, and the aadA1 gene. The aminoglycoside resistance gene, designated aac(6')-Iae, encoded a 183-amino-acid protein that shared 57.1% identity with AAC(6')-Iq. Recombinant AAC(6')-Iae protein showed aminoglycoside 6'-N-acetyltransferase activity by thin-layer chromatography. Escherichia coli expressing exogenous aac(6')-Iae showed resistance to amikacin, dibekacin, isepamicin, kanamycin, netilmicin, sisomicin, and tobramycin but not to arbekacin, gentamicins, or streptomycin. Alterations of gyrA and parC at the amino acid sequence level were detected in IMCJ2.S1, suggesting that such mutations confer the resistance to fluoroquinolones observed for this strain. These results indicate that P. aeruginosa IMCJ2.S1 has developed multidrug resistance by acquiring resistance determinants, including a novel member of the aac(6')-I family and mutations in drug resistance genes.

  19. Emergence of a novel multidrug-resistant Pseudomonas aeruginosa strain producing IMP-type metallo-β-lactamases and AAC(6')-Iae in Japan.

    PubMed

    Kitao, Tomoe; Tada, Tatsuya; Tanaka, Masashi; Narahara, Kenji; Shimojima, Masahiro; Shimada, Kayo; Miyoshi-Akiyama, Tohru; Kirikae, Teruo

    2012-06-01

    The emergence of multidrug-resistant (MDR) Pseudomonas aeruginosa isolates producing IMP-type metallo-β-lactamases (MBLs) and aminoglycoside 6'-N-acetyltransferase [AAC(6')-Iae] has become a serious problem in medical settings in Japan. A total of 217 MDR P. aeruginosa isolates were obtained from August 2009 to April 2010 from patients at 144 hospitals in Japan, of which 145 (66.8%) were positive for IMP-type MBLs and AAC(6')-Iae when tested with an immunochromatographic assay. Polymerase chain reaction (PCR) showed that these isolates were also positive for blaIMP and aac(6')-Iae genes. When these IMP-type MBL- and AAC(6')-Iae-producing isolates were analysed by pulsed-field gel electrophoresis (PFGE), two clusters (I and II) were detected. Most of the isolates (88.3%; 128/145) were grouped under cluster I and had multilocus sequence type ST235 and serotype O11, except for one isolate that was ST991 and serotype O3. The isolates were mainly isolated from the urinary tract (82/145; 56.6%) and respiratory tract (58/145; 40.0%). The epidemiological properties of the isolates belonging to cluster I were similar to those of MDR P. aeruginosa isolates that have been previously reported in Japan. The remaining 16 isolates belonged to cluster II, had identical PFGE patterns and were multilocus sequence type ST991 and serotype O18; all of these isolates were isolated from the respiratory tract. The properties of isolates belonging to cluster II have not been previously described, indicating that a novel IMP-type MBL- and AAC(6')-Iae producing P. aeruginosa strain is emerging in Japan. Isolates belonging to both clusters were isolated from different parts of the country.

  20. “We definitely need an audience”: experiences of Twitter, Twitter networks and tweet content in adults with severe communication disabilities who use augmentative and alternative communication (AAC)

    PubMed Central

    Hemsley, Bronwyn; Dann, Stephen; Palmer, Stuart; Allan, Meredith; Balandin, Susan

    2015-01-01

    Abstract Purpose: The aim of this study was to investigate the Twitter experiences of adults with severe communication disabilities who use augmentative and alternative communication (AAC) to inform Twitter training and further research on the use of Twitter in populations with communication disabilities. Method: This mixed methods research included five adults with severe communication disabilities who use AAC. It combined (a) quantitative analysis of Twitter networks and (b) manual coding of tweets with (c) narrative interviews with participants on their Twitter experiences and results. Results: The five participants who used AAC and Twitter were diverse in their patterns and experiences of using Twitter. Twitter networks reflected interaction with a close-knit network of people rather than with the broader publics on Twitter. Conversational, Broadcast and Pass Along tweets featured most prominently, with limited use of News or Social Presence tweets. Tweets appeared mostly within each participant's micro- or meso-structural layers of Twitter. Conclusions: People who use AAC report positive experiences in using Twitter. Obtaining help in Twitter, and engaging in hashtag communities facilitated higher frequency of tweets and establishment of Twitter networks. Results reflected an inter-connection of participant Twitter networks that might form part of a larger as yet unexplored emergent community of people who use AAC in Twitter.Implications for RehabilitationTwitter can be used as an important vehicle for conversation and a forum for people with communication disabilities to exchange information and participate socially in online communities.It is important that information and resources relating to the effective use of Twitter for a range of purposes are made available to people with communication disabilities who wish to take up or maintain use of Twitter.People with communication disabilities might benefit from support in using Twitter to meet their goals

  1. Impact of post-infiltration soil aeration at different growth stages of sub-surface trickle-irrigated tomato plants

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Jia, Zong-xia; Niu, Wen-Quan; Wang, Jing-wei

    2016-07-01

    Sensitivity to low rhizosphere soil aeration may change over time and therefore plant response may also depend on different growth stages of a crop. This study quantified effects of soil aeration during 5 different periods, on growth and yield of trickle-irrigated potted single tomato plants. Irrigation levels were 0.6 to 0.7 (low level) or 0.7 to 0.8 (high level) of total water holding capacity of the pots. Soil was aerated by injecting 2.5 l of air into each pot through the drip tubing immediately after irrigation. Fresh fruit yield, above ground plant dry weight, plant height, and leaf area index response to these treatments were measured. For all these 4 response variables, means of post-infiltration aeration between 58 to 85 days after sowing were 13.4, 43.5, 13.7, and 37.7% higher than those for the non-aerated pots, respectively. The results indicated that: post-infiltration soil aeration can positively impact the yield and growth of sub-surface trickle-irrigated potted tomato plants; positive effects on plant growth can be obtained with aeration during the whole growth period or with aeration for partial periods; positive growth effects of partial periods of aeration appears to persist and result in yield benefit.

  2. Effect of artificial aeration on the performance of vertical-flow constructed wetland treating heavily polluted river water.

    PubMed

    Dong, Huiyu; Qiang, Zhimin; Li, Tinggang; Jin, Hui; Chen, Weidong

    2012-01-01

    Three lab-scale vertical-flow constructed wetlands (VFCWs), including the non-aerated (NA), intermittently aerated (IA) and continuously aerated (CA) ones, were operated at different hydraulic loading rates (HLRs) to evaluate the effect of artificial aeration on the treatment efficiency of heavily polluted river water. Results indicated that artificial aeration increased the dissolved oxygen (DO) concentrations in IA and CA, which significantly favored the removal of organic matter and NH(4+)-N. The DO grads caused by intermittent aeration formed aerobic and anoxic regions in IA and thus promoted the removal of total nitrogen (TN). Although the removal efficiencies of COD(Cr), NH(4+)-N and TN in the three VFCWs all decreased with an increase in HLR, artificial aeration enhanced the reactor resistance to the fluctuation of pollutant loadings. The maximal removal efficiencies of COD(Cr), NH(4+)-N and total phosphorus (TP) (i.e., 81%, 87% and 37%, respectively) were observed in CA at 19 cm/day HLR, while the maximal TN removal (i.e., 57%) was achieved in IA. Although the improvement of artificial aeration on TP removal was limited, this study has demonstrated the feasibility of applying artificial aeration to VFCWs treating polluted river water, particularly at a high HLR.

  3. Concrete Mixing Methods and Concrete Mixers: State of the Art.

    PubMed

    Ferraris, C F

    2001-01-01

    As for all materials, the performance of concrete is determined by its microstructure. Its microstructure is determined by its composition, its curing conditions, and also by the mixing method and mixer conditions used to process the concrete. This paper gives an overview of the various types of mixing methods and concrete mixers commercially available used by the concrete industry. There are two main types of mixers used: batch mixers and continuous mixers. Batch mixers are the most common. To determine the mixing method best suited for a specific application, factors to be considered include: location of the construction site (distance from the batching plant), the amount of concrete needed, the construction schedule (volume of concrete needed per hour), and the cost. Ultimately, the quality of the concrete produced determines its performance after placement. An important measure of the quality is the homogeneity of the material after mixing. This paper will review mixing methods in regards to the quality of the concrete produced. Some procedures used to determine the effectiveness of the mixing will be examined.

  4. Concrete Mixing Methods and Concrete Mixers: State of the Art

    PubMed Central

    Ferraris, Chiara F.

    2001-01-01

    As for all materials, the performance of concrete is determined by its microstructure. Its microstructure is determined by its composition, its curing conditions, and also by the mixing method and mixer conditions used to process the concrete. This paper gives an overview of the various types of mixing methods and concrete mixers commercially available used by the concrete industry. There are two main types of mixers used: batch mixers and continuous mixers. Batch mixers are the most common. To determine the mixing method best suited for a specific application, factors to be considered include: location of the construction site (distance from the batching plant), the amount of concrete needed, the construction schedule (volume of concrete needed per hour), and the cost. Ultimately, the quality of the concrete produced determines its performance after placement. An important measure of the quality is the homogeneity of the material after mixing. This paper will review mixing methods in regards to the quality of the concrete produced. Some procedures used to determine the effectiveness of the mixing will be examined. PMID:27500029

  5. 3-D Numerical Simulation for Gas-Liquid Two-Phase Flow in Aeration Tank

    NASA Astrophysics Data System (ADS)

    Xue, R.; Tian, R.; Yan, S. Y.; Li, S.

    In the crafts of activated sludge treatment, oxygen supply and the suspending state of activated sludge are primary factors to keep biochemistry process carrying on normally. However, they are all controlled by aeration. So aeration is crucial. The paper focus on aeration, use CFD software to simulate the field of aeration tank which is designed by sludge load method. The main designed size of aeration tank is: total volume: 20 000 m3; corridor width: 8m; total length of corridors: 139m; number of corridors: 3; length of one single corridor: 48m; effective depth: 4.5m; additional depth: 0.5m. According to the similarity theory, a geometrical model is set up in proportion of 10:1. The way of liquid flow is submerge to avoid liquid flow out directly. The grid is plotted by dividing the whole computational area into two parts. The bottom part which contains gas pipe and gas exit hole and the above part which is the main area are plotted by tetrahedron and hexahedron respectively. In boundary conditions, gas is defined as the primary-phase, and liquid is defined as the secondary-phase. Choosing mixture model, two-phase flow field of aeration tank is simulated by solved the Continuity equation for the mixture, Momentum equation for the mixture, Volume fraction equation for the secondary phases and Relative velocity formula when gas velocity is 10m/s, 20m/s, 30m/s. what figure shows is the contour of velocity magnitude for the mixture phase when gas velocity is 20m/s. Through analysis, the simulation tendency is agreed with actual running of aeration tank. It is feasible to use mixture model to simulate flow field of aeration tank by fluent software. According to the simulation result, the better velocity of liquid or gas (the quantity of inlet air) can be chosen by lower cost, and also the performance of aeration tank can be forecast. It will be helpful for designing and operation.

  6. Corrosion control of steel-reinforced concrete

    NASA Astrophysics Data System (ADS)

    Chung, D. D. L.

    2000-10-01

    The methods and materials for corrosion control of steel-reinforced concrete are reviewed. The methods are steel surface treatment, the use of admixtures in concrete, surface coating on concrete, and cathodic protection.

  7. Monitoring transitory profiles of leachate humic substances in landfill aeration reactors in mesophilic and thermophilic conditions.

    PubMed

    Tong, Huanhuan; Yin, Ke; Ge, Liya; Giannis, Apostolos; Chuan, Valerie W L; Wang, Jing-Yuan

    2015-04-28

    The presence of humic substances (HS) in landfill leachate is of great interest because of their structural stability and potential toxicity. This study examined the effects of temperature and waste age on the transformation of HS during in situ aeration of bioreactor landfills. By establishing aerobic conditions, dissolved organic carbon (DOC) rapidly accumulated in the bioreactor leachate. Fractional analysis showed that the elevated concentration of humic acids (HAs) was primarily responsible for the increment of leachate strength. Further structural characterization indicated that the molecular weight (MW) and aromacity of HS were enhanced by aeration in conjunction with thermophilic temperature. Interestingly, elevation of HAs concentration was not observed in the aeration reactor with a prolonged waste age, as the mobility of HAs was lowered by the high MW derived from extended waste age. Based on these results, aeration may be more favorable in aged landfills, since dissolution of HAs could be minimized by the evolution to larger MW compared to young landfills. Moreover, increased operation temperature during aeration likely offers benefits for the rapid maturation of HS.

  8. Performance of a fixed-bed biofilm reactor with microbubble aeration in aerobic wastewater treatment.

    PubMed

    Zhang, Lei; Liu, Junliang; Liu, Chun; Zhang, Jing; Yang, Jingliang

    2016-01-01

    Microbubble aeration is supposed to be highly efficient for oxygen supply in aerobic wastewater treatment. In the present study, the performance of a fixed-bed biofilm reactor microbubble-aerated using a Shirasu porous glass (SPG) membrane system was investigated when treating synthetic municipal wastewater. The biofilm formation on the carriers was enhanced with microbubble aeration due to the strong adhesion of microbubbles to the solid surface. The dissolved oxygen concentration, the removals of chemical oxygen demand (COD) and nitrogen, and the oxygen utilization efficiency were influenced by the organic loading rate at a certain oxygen supply capacity. The relatively optimal organic loading rate was determined as 0.82 kgCOD/(m(3)d) when the oxygen supply capacity was 0.93 kgO(2)/(m(3)d), where COD and ammonia removal efficiencies were 91.7% and 53.9%, respectively. The corresponding SPG membrane area-based COD removal capacity was 6.88 kgCOD/(m(2)d). The oxygen utilization efficiency of microbubble aeration was obviously higher compared to conventional bubble aeration. The simultaneous nitrification and denitrification occurred in the biofilm reactor and the total nitrogen removal efficiency of 50.4% was achieved under these conditions. In addition, the increase in air supply capacity of the SPG membrane system was suggested to improve its energy utilization efficiency. PMID:27386991

  9. Municipal waste stabilization in a reactor with an integrated active and passive aeration system.

    PubMed

    Kasinski, Slawomir; Slota, Monika; Markowski, Michal; Kaminska, Anna

    2016-04-01

    To test whether an integrated passive and active aeration system could be an effective solution for aerobic decomposition of municipal waste in technical conditions, a full-scale composting reactor was designed. The waste was actively aerated for 5d, passively aerated for 35 d, and then actively aerated for 5d, and the entire composting process was monitored. During the 45-day observation period, changes in the fractional, morphological and physico-chemical characteristics of the waste at the top of the reactor differed from those in the center of the reactor. The fractional and morphological analysis made during the entire process of stabilization, showed the total reduction of organic matter measured of 82 wt% and 86 wt% at the respective depths. The reduction of organic matter calculated using the results of Lost of Ignition (LOI) and Total Organic Carbon (TOC) showed, respectively, 40.51-46.62% organic matter loss at the top and 45.33-53.39% in the center of the reactor. At the end of the process, moisture content, LOI and TOC at the top were 3.29%, 6.10% and 4.13% higher, respectively, than in the center. The results showed that application of passive aeration in larger scale simultaneously allows the thermophilic levels to be maintained during municipal solid waste composting process while not inhibiting microbial activity in the reactor.

  10. Landfill aeration within the scope of post-closure care and its completion.

    PubMed

    Ritzkowski, Marco; Stegmann, Rainer

    2013-10-01

    The time frame required for post-closure care of Municipal Solid Waste (MSW) landfills is often assessed over several decades or centuries. One possibility to significantly shorten this period and, at the same time, improve the emission behavior exists with in situ aeration. Positive effects in connection with this method for biological stabilization have been investigated and published elsewhere. However, until today neither generally accepted monitoring guidelines nor completion criteria have been defined. With the paper on hand the authors propose a methodology for the assessment of both, total and remaining stabilization periods for aerated landfills. The central component of this methodology is a carbon balance. The latter is based on a detailed waste characterization in combination with online monitoring of the emissions (gas and leachate). The methodology is exemplarily demonstrated by means of data derived from a full scale project in Northern Germany. Here it could be shown that the predicted aeration period of approximately 6.4years was sufficient to bio-stabilize the landfill. Furthermore, proposals for the completion of landfill aeration are presented. In this connection, carbon balance is of particular importance since the amount of biodegradable organic carbon mainly determines the emission potential. Additional parameters, aiming at a validation of the state of biological stabilization achieved during aeration are proposed and described.

  11. [Effect of Intermittent Aeration on Nitrogen Removal Efficiency in Vertical Subsurface Flow Constructed Wetland].

    PubMed

    Wang, Jian; Li, Huai-zheng; Zhen, Bao-chong; Liu, Zhen-dong

    2016-03-15

    One-stage vertical subsurface flow constructed wetlands (CWs) were used to treat effluent from grit chamber in municipal wastewater treatment plant. The CW was divided into aerobic zone and anoxic zone by means of raising the effluent level and installing a perforated pipe. Two parameters (the ratio of aeration time and nonaeration time, aeration cycle) were optimized in the experiment to enhance nitrogen removal efficiency. The results suggested that the removal rates of COD and NH₄⁺-N increased while TN showed a trend of first increasing and then decreasing with the increasing ratio. When the ratio was 3:1, the C/N value in the anoxic zone was 4. 8. And the TN effluent concentration was 15.8 mg · L⁻¹ with the highest removal rate (62.1%), which was increased by 12.7% compared with continuous aeration. As the extension of the aeration cycle, the DO effluent concentration as well as the removal rates of COD and NH: -N declined gradually. The TN removal rate reached the maximum (65.5%) when the aeration cycle was 6h. However, the TN removal rate dropped rapidly when the cycle exceeded the hydraulic retention time in the anoxic zone.

  12. Nitrogen transformations and retention in planted and artificially aerated constructed wetlands.

    PubMed

    Maltais-Landry, Gabriel; Maranger, Roxane; Brisson, Jacques; Chazarenc, Florent

    2009-02-01

    Nitrogen (N) processing in constructed wetlands (CWs) is often variable, and the contribution to N loss and retention by various pathways (nitrification/denitrification, plant uptake and sediment storage) remains unclear. We studied the seasonal variation of the effects of artificial aeration and three different macrophyte species (Phragmites australis, Typha angustifolia and Phalaris arundinacea) on N processing (removal rates, transformations and export) using experimental CW mesocosms. Removal of total nitrogen (TN) was higher in summer and in planted and aerated units, with the highest mean removal in units planted with T. angustifolia. Export of ammonium (NH(4)(+)), a proxy for nitrification limitation, was higher in winter, and in unplanted and non-aerated units. Planted and aerated units had the highest export of oxidized nitrogen (NO(y)), a proxy for reduced denitrification. Redox potential, evapotranspiration (ETP) rates and hydraulic retention times (HRT) were all predictors of TN, NH(4)(+) and NO(y) export, and significantly affected by plants. Denitrification was the main N sink in most treatments accounting for 47-62% of TN removal, while sediment storage was dominant in unplanted non-aerated units and units planted with P. arundinacea. Plant uptake accounted for less than 20% of the removal. Uncertainties about the long-term fate of the N stored in sediments suggest that the fraction attributed to denitrification losses could be underestimated in this study.

  13. Expired CO2 Levels Indicate Degree of Lung Aeration at Birth

    PubMed Central

    Hooper, Stuart B.; Fouras, Andreas; Siew, Melissa L.; Wallace, Megan J.; Kitchen, Marcus J.; Pas, Arjan B. te.; Klingenberg, Claus; Lewis, Robert A.; Davis, Peter G.; Morley, Colin J.; Schmölzer, Georg M.

    2013-01-01

    As neonatal resuscitation critically depends upon lung aeration at birth, knowledge of the progression of this process is required to guide ongoing care. We investigated whether expired CO2 (ECO2) levels indicate the degree of lung aeration immediately after birth in two animal models and in preterm infants. Lambs were delivered by caesarean section and ventilated from birth. In lambs, ECO2 levels were significantly (p<0.0001) related to tidal volumes and CO2 clearance/breath increased exponentially when tidal volumes were greater than 6 mL/kg. Preterm (28 days of gestation; term = 32 days) rabbits were also delivered by caesarean section and lung aeration was measured using phase contrast X-ray imaging. In rabbit kittens, ECO2 levels were closely related (p<0.001) to lung volumes at end-inflation and were first detected when ∼7% of the distal lung regions were aerated. ECO2 levels in preterm infants at birth also correlated with tidal volumes. In each infant, ECO2 levels increased to >10 mmHg 28 (median) (21–36) seconds before the heart rate increased above 100 beats per minute. These data demonstrate that ECO2 levels can indicate the relative degree of lung aeration after birth and can be used to clinically assess ventilation in the immediate newborn period. PMID:23951032

  14. Limited aeration of methanogenic systems for treatment of sulfate-containing wastewater

    SciTech Connect

    Zitomer, D.H.; Shrout, J.D.

    1998-07-01

    Wastewaters with high sulfate concentrations are often not readily amenable to methanogenic treatment due to production of potentially inhibitory hydrogen sulfide. Some reports indicate that treatment has been enhanced by air sparging of recycle flows to air-strip hydrogen sulfide and create a selective environment for reduction of sulfate to elemental sulfur, rather than sulfides and thiosulfate. In this report, direct aeration of methanogenic expanded beds was employed for treatment of high-sulfate wastewater and compared to a strictly anaerobic control. An influent wastewater COD:SO{sup {minus}2}{sub 4} ratio as low as 4,4:1 did not discernibly inhibit methane production in the anaerobic control. At a relatively high OLR of 30g COD/L{sub A}-d and a relatively short HRT of 4.2 hours, the COD removal of the control was 97%. Methanogenesis was also sustained in the aerated reactors which had oxygen transfer rates of between 2 to 5% of the OLR. These aerated reactors converted approximately 70% of the COD to methane. Future research will involve higher sulfate loadings and aeration rates to determine possible benefits of direct aeration of methanogenic expanded beds.

  15. Raising and controlling study of dissolved oxygen concentration in closed-type aeration tank.

    PubMed

    Chen, C K; Lo, S L

    2005-07-01

    This study investigated the promotion and control of dissolved oxygen (DO) concentration of the closed-type aeration tank via practical experiments in the wastewater treatment system of a 5-star hotel in Taipei. As with limited and treasured space in Taiwan, before the completion of the sewer system construction in cities, to utilize the mat foundation under large buildings as the space of sewage treatment plant still has been one of the alternatives of those sewage treatments. However, aeration tanks constructed in the mat foundation of buildings have smaller effective water depth, which will cause a lower total transfer amount of DO. Controlling the total exhaust gas flow rate can increase the pressure on such closed-type aeration tanks. The DO concentration thus may increase according to Henry's Law. Furthermore, it may enable operators to adjust the DO concentration of the aeration tank more precisely and thus sustain optimal operating conditions in these treatment facilities. Practical experiments indicated that the DO concentration of aeration tank maintains an average of 3.8 mg l(-1), obtaining the optimum operating conditions. The efficiency of the biological treatment facilities in the mat foundation could be markedly improved. PMID:16080335

  16. Aerated Shewanella oneidensis in continuously fed bioelectrochemical systems for power and hydrogen production.

    PubMed

    Rosenbaum, Miriam; Cotta, Michael A; Angenent, Largus T

    2010-04-01

    We studied the effects of aeration of Shewanella oneidensis on potentiostatic current production, hydrogen production in a microbial electrolysis cell, and electric power generation in a microbial fuel cell (MFC). The potentiostatic performance of aerated S. oneidensis was considerably enhanced to a maximum current density of 0.45 A/m(2) or 80.3 A/m(3) (mean: 0.34 A/m(2), 57.2 A/m(3)) compared to anaerobically grown cultures. Biocatalyzed hydrogen production rates with aerated S. oneidensis were studied within the applied potential range of 0.3-0.9 V and were highest at 0.9 V with 0.3 m(3) H(2)/m(3) day, which has been reported for mixed cultures, but is approximately 10 times higher than reported for an anaerobic culture of S. oneidensis. Aerated MFC experiments produced a maximum power density of 3.56 W/m(3) at a 200-Omega external resistor. The main reasons for enhanced electrochemical performance are higher levels of active biomass and more efficient substrate utilization under aerobic conditions. Coulombic efficiencies, however, were greatly reduced due to losses of reducing equivalents to aerobic respiration in the anode chamber. The next challenge will be to optimize the aeration rate of the bacterial culture to balance between maximization of bacterial activation and minimization of aerobic respiration in the culture.

  17. Maximization of beta-galactosidase production: a simultaneous investigation of agitation and aeration effects.

    PubMed

    Alves, Fernanda Germano; Filho, Francisco Maugeri; de Medeiros Burkert, Janaína Fernandes; Kalil, Susana Juliano

    2010-03-01

    In this work, the agitation and aeration effects in the maximization of the beta-galactosidase production from Kluyveromyces marxianus CCT 7082 were investigated simultaneously, in relation to the volumetric enzyme activity and the productivity, as well as the analysis of the lactose consumption and production of glucose, and galactose of this process. Agitation and aeration effects were studied in a 2 L batch stirred reactor. A central composite design (2(2) trials plus three central points) was carried out. Agitation speed varied from 200 to 500 rpm and aeration rate from 0.5 to 1.5 vvm. It has been shown in this study that the volumetric enzyme production was strongly influenced by mixing conditions, while aeration was shown to be less significant. Linear models for activity and productivity due to agitation and aeration were obtained. The favorable condition was 500 rpm and 1.5 vvm, which lead to the best production of 17 U mL(-1) for enzymatic activity, 1.2 U mL(-1) h(-1) for productivity in 14 h of process, a cellular concentration of 11 mg mL(-1), and a 167.2 h(-1) volumetric oxygen transfer coefficient. PMID:19517069

  18. Performance of intermittent aeration reactor on NH4-N removal from groundwater resources.

    PubMed

    Khanitchaidecha, W; Nakamura, T; Sumino, T; Kazama, F

    2010-01-01

    To study the effect of intermittent aeration period on ammonium-nitrogen (NH4-N) removal from groundwater resources, synthetic groundwater was prepared and three reactors were operated under different conditions--"reactor A" under continuous aeration, "reactor B" under 6 h intermittent aeration, and "reactor C" under 2 h intermittent aeration. To facilitate denitrification simultaneously with nitrification, "acetate" was added as an external carbon source with step-wise increase from 0.5 to 1.5 C/N ratio, where C stands for total carbon content in the system, and N for NH4-N concentration in the synthetic groundwater. Results show that complete NH4-N removal was obtained in "reactor B" and "reactor C" at 1.3 and 1.5 C/N ratio respectively; and partial NH4-N removal in "reactor A". These results suggest that intermittent aeration at longer interval could enhance the reactor performance on NH4-N removal in terms of efficiency and low external carbon requirement. Because of consumption of internal carbon by the process, less amount of external carbon is required. Further increase in carbon in a form of acetate (1.5 to 2.5 C/N ratios) increases removal rate (represented by reaction rate coefficient (k) of kinetic equation) as well as occurrence of free cells. It suggests that the operating condition at reactor B with 1.3 C/N ratio is more appropriate for long-term operation at a pilot-scale.

  19. [Effect of Intermittent Aeration on Nitrogen Removal Efficiency in Vertical Subsurface Flow Constructed Wetland].

    PubMed

    Wang, Jian; Li, Huai-zheng; Zhen, Bao-chong; Liu, Zhen-dong

    2016-03-15

    One-stage vertical subsurface flow constructed wetlands (CWs) were used to treat effluent from grit chamber in municipal wastewater treatment plant. The CW was divided into aerobic zone and anoxic zone by means of raising the effluent level and installing a perforated pipe. Two parameters (the ratio of aeration time and nonaeration time, aeration cycle) were optimized in the experiment to enhance nitrogen removal efficiency. The results suggested that the removal rates of COD and NH₄⁺-N increased while TN showed a trend of first increasing and then decreasing with the increasing ratio. When the ratio was 3:1, the C/N value in the anoxic zone was 4. 8. And the TN effluent concentration was 15.8 mg · L⁻¹ with the highest removal rate (62.1%), which was increased by 12.7% compared with continuous aeration. As the extension of the aeration cycle, the DO effluent concentration as well as the removal rates of COD and NH: -N declined gradually. The TN removal rate reached the maximum (65.5%) when the aeration cycle was 6h. However, the TN removal rate dropped rapidly when the cycle exceeded the hydraulic retention time in the anoxic zone. PMID:27337890

  20. Biodecontamination of radionuclide contaminated concrete

    SciTech Connect

    Hamilton, M.A.; Rogers, R.D.; Benson, J.

    1996-10-01

    Within the nuclear industry, there are literally hundreds of square miles of radionuclide contaminated concrete surfaces. A novel technology for biologically decontaminating concrete is being developed. The technology exploits a naturally occurring phenomenon referred to as microbially influenced degradation (MID) in which bacteria produce acids that dissolve the cement matrix of the concrete. Accelerated testing in laboratory conditions was conducted. The bacteria Thiobacillus thiooxidans, supplied from a continuous flow bioreactor, was applied to an exposed concrete surface. A control chamber exposing concrete to sterile media was operated under the same conditions. One hundred percent of surrogate cobalt contamination was recovered from the Thiobacillus treated concrete and 1 mm thickness of concrete material was removed in 60 days. Prototype chambers that can be mounted directly to concrete surfaces have been designed to allow control of environmental conditions to promote MID after inoculation of the surface with bacteria. Studies to determine optimum source and quantity of reduced sulfur, bacterial species or consortia best suited for rapid MID, and methods of application and delivery of bacteria and nutrients will be discussed.

  1. Concrete Masonry Designs: Educational Issue.

    ERIC Educational Resources Information Center

    Hertzberg, Randi, Ed.

    2001-01-01

    This special journal issue addresses concrete masonry in educational facilities construction. The issue's feature articles are: (1) "It Takes a Village To Construct a Massachusetts Middle School," describing a middle school constructed almost entirely of concrete masonry and modeled after a typical small New England village; (2) "Lessons Learned,"…

  2. The Concrete and Pavement Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2012-01-01

    The modern world is characterized by the extensive use of concrete and asphalt pavement. Periodically, these materials are replaced and the old materials disposed of. In this challenge, students will be asked to develop ways to reuse the old materials. It is important for students to understand how concrete and asphalt are made and applied, as…

  3. Molded Concrete Center Mine Wall

    NASA Technical Reports Server (NTRS)

    Lewis, E. V.

    1987-01-01

    Proposed semiautomatic system forms concrete-foam wall along middle of coal-mine passage. Wall helps support roof and divides passage into two conduits needed for ventilation of coal face. Mobile mold and concrete-foam generator form sections of wall in place.

  4. Technology Solutions Case Study: Insulating Concrete Forms

    SciTech Connect

    none,

    2012-10-01

    This Pacific Northwest National Laboratory project investigated insulating concrete forms—rigid foam, hollow walls that are filled with concrete for highly insulated, hurricane-resistant construction.

  5. [Effect of intermittent artificial aeration on nitrogen and phosphorus removal in subsurface vertical-flow constructed wetlands].

    PubMed

    Tang, Xian-qiang; Li, Jin-zhong; Li, Xue-Ju; Liu, Xue-gong; Huang, Sui-liang

    2008-04-01

    Shale and T. latifolia were used as subsurface vertical-flow constructed wetland substrate and vegetation for eutrophic Jin River water treatment, and investigate the effect of intermittent aeration on nitrogen and phosphorus removal. In this study, hydraulic loading rate was equal to 800 mm/d, and ratio of air and water was 5:1. During the entire running period, maximal monthly mean ammonia-nitrogen (NH4+ -N), total nitrogen (TN), soluble reactive phosphorus (SRP) and total phosphorus (TP) removal rates were observed in August 2006. In contrast to the non-aerated wetland, aeration enhanced ammonia-nitrogen, total nitrogen, soluble reactive phosphorus and total phosphorus removal: 10.1%, 4.7%, 10.2% and 8.8% for aeration in the middle, and 25.1%, 10.0%, 7.7% and 7.4% for aeration at the bottom of the substrate, respectively. However, aeration failed to improve the nitrate-nitrogen removal. During the whole experimental period, monthly mean NO3(-) -N removal rates were much lower for aerated constructed wetlands (regarding aeration in the middle and at the bottom) than those for non-aerated system. After finishing the experiment, aboveground plant biomass (stems and leaves) of T. latifolia was harvested, and its weight and nutrient content (total nitrogen and total phosphorus) were measured. Analysis of aboveground plant biomass indicated that intermittent aeration restrained the increase in biomass but stimulated assimilation of nitrogen and phosphorus into stems and leaves. Additional total nitrogen removal of 11.6 g x m(-2) and 12.6 g x m(-2) by aboveground T. latifolia biomass for intermittent artificial aeration in the middle and at the bottom of the wetland substrate, respectively, was observed.

  6. Towards integrated operation of membrane bioreactors: effects of aeration on biological and filtration performance.

    PubMed

    Dalmau, M; Monclús, H; Gabarrón, S; Rodriguez-Roda, I; Comas, J

    2014-11-01

    Two experimental studies evaluated the effect of aerobic and membrane aeration changes on sludge properties, biological nutrient removal and filtration processes in a pilot plant membrane bioreactor. The optimal operating conditions were found at an aerobic dissolved oxygen set-point (DO) of 0.5 mg O2 L(-1) and a membrane specific aeration demand (SADm) of 1 m h(-1), where membrane aeration can be used for nitrification. Under these conditions, a total flow reduction of 42% was achieved (75% energy reduction) without compromising nutrient removal efficiencies, maintaining sludge characteristics and controlled filtration. Below these optimal operating conditions, the nutrient removal efficiency was reduced, increasing 20% for soluble microbial products, 14% for capillarity suction time and reducing a 15% for filterability. Below this DO set-point, fouling increased with a transmembrane pressure 75% higher. SADm below 1 m h(-1) doubled the values of transmembrane pressure, without recovery after achieving the initial conditions.

  7. Bioethanol production from the hydrolysate of rape stem in a surface-aerated fermentor.

    PubMed

    Yeon, Ji-Hyeon; Lee, Sang-Eun; Choi, Woon Yong; Choi, Won-Seok; Kim, Il-Chul; Lee, Hyeon-Yong; Jung, Kyung-Hwan

    2011-01-01

    In this study, we investigated the feasibility of producing bioethanol from the hydrolysate of rape stem. Specifically, the most ideal yeast strain was screened, and the microaeration was performed by surface aeration on a liquid medium surface. Among the yeast strains examined, Pichia stipitis CBS 7126 displayed the best performance in bioethanol production during the surface-aerated fermentor culture. Pichia stipitis CBS 7126 produced maximally 9.56 g/l of bioethanol from the initial total reducing sugars (about 28 g/l). The bioethanol yield was 0.397 (by the DNS method). Furthermore, this controlled surface aeration method holds promise for use in the bioethanol production from the xylose-containing lignocellulosic hydrolysate of biomass.

  8. Wastewater treatment with bacteria immobilized onto a ceramic carrier in an aerated system.

    PubMed

    Kariminiaae-Hamedaani, Hamid-Reza; Kanda, Kohzo; Kato, Fumio

    2003-01-01

    Biological treatment of the wastewater discharged from a food processing factory was continuously carried out in a packed bed bioreactor under aerobic conditions. The bacterium isolated from the wastewater was immobilized onto a new type of ceramic carrier by a vacuum method and high numbers of bacteria were colonized onto the carrier (2.9 x 10(9) cfu/g of dry ceramic carrier). The effect of the hydraulic retention time (HRT) and aeration rate on the removal of the chemical oxygen demand (COD) was investigated. The system was able on average to remove more than 82% of the influent COD during 160 d of operation and more than 87% of the influent COD on average was removed when the HRT was 30.17 h and the aeration rate was 2.0 vvm. Aeration rates in the range of 0.4 to 2.0 vvm do not affect the COD removal efficiency. PMID:16233380

  9. Recovery of ammonia from swine manure using gas-permeable membranes: effect of aeration.

    PubMed

    García-González, M C; Vanotti, M B; Szogi, A A

    2015-04-01

    The gas-permeable membrane process can recover ammonia from manure, reducing pollution whilst converting ammonia into an ammonium salt fertilizer. The process involves manure pH control to increase ammonium (NH4(+)) recovery rate that is normally carried out using an alkali. In this study a new strategy to avoid the use of alkali was tested applying low-rate aeration and nitrification inhibition. The wastewater used was raw swine manure with 2390 mg NH4(+)-N/L. Results showed that aeration increased pH above 8.5 allowing quick transformation of NH4(+) into gaseous ammonia (NH3) and efficient recovery by permeation through the submerged membrane. The overall NH4(+) recovery obtained with aeration was 98% and ammonia emissions losses were less than 1.5%. The new approach can substitute large amounts of alkali chemicals needed to obtain high NH4(+) recovery with important economic and environmental savings. PMID:25602923

  10. RBF methods for solving laterally averaged Saint Venant equations: application to eutrophication prevention through aeration

    NASA Astrophysics Data System (ADS)

    Halassi, A.; Ouazar, D.; Taik, A.

    2015-10-01

    A vertical 2Dxz laterally averaged hydrodynamic model is presented in this paper to study the aeration process in lakes. The system exhibits highly nonlinear behaviour due to the phenomena involved such as stratification, air concentration, and convective terms. The suggested model is used to simulate mechanical aeration to overcome and prevent the eutrophication in lakes. The multiquadric radial basis functions are used to solve numerically the governing partial differential equations. Because of the difficulty and the complexity when choosing a suitable shape parameter in radial basis functions, an alternative way is introduced in this work to overcome these difficulties. A validation study is carried out using several test examples, including Poisson, Navier-Stokes and transport equations. Finally, the proposed model is first applied to simulate a squared domain aeration problem and then a real test case has been considered. The obtained results are in good agreement with the results reported in the literature.

  11. Greenhouse gas production and efficiency of planted and artificially aerated constructed wetlands.

    PubMed

    Maltais-Landry, Gabriel; Maranger, Roxane; Brisson, Jacques; Chazarenc, Florent

    2009-03-01

    Greenhouse gas (GHG) emissions by constructed wetlands (CWs) could mitigate the environmental benefits of nutrient removal in these man-made ecosystems. We studied the effect of 3 different macrophyte species and artificial aeration on the rates of nitrous oxide (N(2)O), carbon dioxide (CO(2)) and methane (CH(4)) production in CW mesocosms over three seasons. CW emitted 2-10 times more GHG than natural wetlands. Overall, CH(4) was the most important GHG emitted in unplanted treatments. Oxygen availability through artificial aeration reduced CH(4) fluxes. Plant presence also decreased CH(4) fluxes but favoured CO(2) production. Nitrous oxide had a minor contribution to global warming potential (GWP<15%). The introduction of oxygen through artificial aeration combined with plant presence, particularly Typha angustifolia, had the overall best performance among the treatments tested in this study, including lowest GWP, greatest nutrient removal, and best hydraulic properties.

  12. Bioremediation of 2,4,6-trinitrotoluene-contaminated soils by two different aerated compost systems.

    PubMed

    Breitung, J; Bruns-Nagel, D; Steinbach, K; Kaminski, L; Gemsa, D; von Löw, E

    1996-02-01

    Two composting systems were compared on a laboratory scale as a bioremediation technology for degradation or immobilization of 2,4,6-trinitrotoluene (TNT) in contaminated soils. The first compost was aerated from the beginning whereas the second compost was only aerated after an anaerobic prephase of 65 days. In the first compost system the TNT concentration declined rapidly by 92% but, at the end, TNT could be partially recovered. During the anaerobic prephase of the second compost system, TNT was almost completely converted to aminodinitrotoluenes, which during the subsequent aeration almost entirely disappeared. In addition, the second compost generated less toxic material than the first one as confirmed by inhibition of bioluminescence of Vibrio fischeri. These data show that microbiological TNT-degradation systems can be successfully designed which are prerequisite for an efficient bioremediation of contaminated soils.

  13. The Puzzle of Septarian Concretions

    NASA Astrophysics Data System (ADS)

    John, C. M.; Dale, A.; Mozley, P.; Smalley, P. C.; Muggeridge, A. H.

    2014-12-01

    Carbonate concretions in clastic rocks and their septarian fracture fills act as 'time capsules', capturing the signatures of chemical and biological processes during diagenesis. However, many aspects of the formation of concretions and septarian fractures remain poorly understood, for although concretions occur in clastic rocks throughout the geological record, they are rarely documented in recent shallow-burial environments. Consequently, the depth and temperature at which concretion-forming processes occur are often poorly constrained. Carbonate clumped isotopes have recently been applied successfully to concretions and fracture fills that begin to unravel the conditions for the formation of concretions and septarian fractures. Here, we present carbonate clumped isotope results of fracture fills from eight different concretions from various locations, including multiple phases of fill in 4 concretions. Our results suggest that they precipitated over a range of temperatures (22°C - 85°C) from d18Oporewater values between -12‰ to 3‰ and within different d13Ccarbonate zones. The majority of fills precipitated at lower (<50°C) temperatures, although the fluids were not always meteoric. For 3 concretions containing fractures with multiple phases, the d18Oporewater becomes progressively heavier with each later phase and increasing temperature. The one exception to this is in the Barton Clay Formation (UK) where the fractures must have been continuously filled during exhumation as the latest cement phase is the coolest with a d18Oporewater more 18O-depleted than the earliest phase. Therefore, concretion growth must usually initiate early on (<~1 km burial), and subsequent fracturing is also usually early. However, the fracture infilling can occur over a range of depths and can record the diagenetic history of a formation. We gratefully acknowledge a BP and EPSRC Case Studentship for funding this project, and the Natural History Museum London for providing

  14. Nuclear Power Plant Concrete Structures

    SciTech Connect

    Basu, Prabir; Labbe, Pierre; Naus, Dan

    2013-01-01

    A nuclear power plant (NPP) involves complex engineering structures that are significant items of the structures, systems and components (SSC) important to the safe and reliable operation of the NPP. Concrete is the commonly used civil engineering construction material in the nuclear industry because of a number of advantageous properties. The NPP concrete structures underwent a great degree of evolution, since the commissioning of first NPP in early 1960. The increasing concern with time related to safety of the public and environment, and degradation of concrete structures due to ageing related phenomena are the driving forces for such evolution. The concrete technology underwent rapid development with the advent of chemical admixtures of plasticizer/super plasticizer category as well as viscosity modifiers and mineral admixtures like fly ash and silica fume. Application of high performance concrete (HPC) developed with chemical and mineral admixtures has been witnessed in the construction of NPP structures. Along with the beneficial effect, the use of admixtures in concrete has posed a number of challenges as well in design and construction. This along with the prospect of continuing operation beyond design life, especially after 60 years, the impact of extreme natural events ( as in the case of Fukushima NPP accident) and human induced events (e.g. commercial aircraft crash like the event of September 11th 2001) has led to further development in the area of NPP concrete structures. The present paper aims at providing an account of evolution of NPP concrete structures in last two decades by summarizing the development in the areas of concrete technology, design methodology and construction techniques, maintenance and ageing management of concrete structures.

  15. Response of the ascorbate-glutathione cycle to re-aeration following hypoxia in lupine roots.

    PubMed

    Garnczarska, Małgorzata

    2005-06-01

    The response of the enzymes and metabolites of the ascorbate-glutathione pathway to oxidative stress caused by re-aeration following hypoxia was studied in roots of hydroponically grown lupine (Lupinus luteus L. cv. Juno) seedlings. Lupine roots were deprived of oxygen by subjecting them to hypoxia for 48 and 72 h and then re-aerated for up to 4 h. An increased content of total ascorbate was observed in lupine roots immediately after hypoxia, whereas total glutathione level decreased. However, a significant increase in the reduced forms of both metabolites was found directly after hypoxia. Re-admission of oxygen caused the decrease of the ratios of reduced to oxidized forms of ascorbate and glutathione, indicating oxidative stress. While monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) activity remained unaltered during re-aeration the increase in activities of ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase (GR, EC 1.6.4.2) was observed 30 min after transfer from hypoxic condition. Dehydroascorbate reductase (DHAR, EC 1.8.5.1) activity approached the control level during a whole re-aeration period. Native gel electrophoresis combined with specific activity staining revealed seven isoforms of APX, five isoforms of GR and three different proteins with DHA reductase activity in roots extracts. However, immediately after hypoxic treatment APX-5 isoform and GR-1 isoform were not observed in roots. This experimental system was also used to investigate superoxide anion level in roots utilizing the superoxide anion-specific indicator dihydroethidium (DHE). Intense DHE-derived fluorescence was found in re-aerated root tips as compared to control roots, indicating that re-aeration induced superoxide anion production in hypoxically pretreated roots.

  16. Volatile emissions during storing of green food waste under different aeration conditions.

    PubMed

    Agapiou, A; Vamvakari, J P; Andrianopoulos, A; Pappa, A

    2016-05-01

    Controlled field experiments were carried out for monitoring the emissions of three plastic commercial household waste bins, which were adapted for studying the effect of aeration process in the evolved volatiles, during house storing of green food waste for 2 weeks, prior to collection. Three experimental scenarios were examined based on no aeration ("NA," closed commercial waste bin), diffusion-based aeration ("DA," closed commercial waste bin with tiny holes), and enforced aeration ("EA," closed commercial waste bin with tiny holes and enforced aeration). The monitoring of volatile organic compounds (VOCs) emitted from organic household kitchen waste was performed using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analysis. Portable sensors were also used for monitoring selected gases and parameters of environmental, bioprocess, and health interest (e.g., CO2, O2, H2S, CH4, NH3, % RH, waste temperatures). VOC emissions are strongly dependent on the waste material. The most frequent VOCs identified over the storing waste, showing over 50 % appearance in all examined samples, were terpenes (e.g., di-limonene, beta-myrcene, delta-3-carene, alpha-pinene, alpha-terpinolene, linalool, etc.), sulfides (dimethyl disulfide), aromatics (benzene, 1-methyl-2-(2-propenyl)), alkanes (e.g., decane, dodecane), ketones (2-propanone), esters (e.g., acetic acid ethyl ester, acetic acid methyl ester), and alcohols (e.g., 3-cyclohexen-1-ol, 4-methyl-1-(1-methylethyl)). The prominent role of terpenes in the "pre-compost" odor and especially that of di-limonene was highlighted. In all examined scenarios, the emitted volatiles were increased at raised temperatures and later decreased in time. Aeration of waste bins slightly affected the volatilization process resulting in higher profiles of VOCs; uniformity in the composition of VOCs was also noted. Slight modifications of commercial waste bins may favor the initiation of home composting. PMID

  17. Relationship between ecosystem respiration and aeration constant in open channel dissolved oxygen analysis

    NASA Astrophysics Data System (ADS)

    Parker, S. J.; Butler, A. P.; Heppell, C. M.

    2015-12-01

    Using the open channel diel method of Odum (1956) and the night-time regression method (Hornberger and Kelly, 1985), we analysed a time series of dissolved oxygen (DO) in two slow flowing streams for a two month period in summer 2014 and obtained values for ecosystem respiration and the aeration constant for each day in the period. We then used the standard dissolved oxygen lumped model to generate a DO time series behaviour for one of those rivers selecting respiration and aeration parameters by randomly sampling from the values obtained from the data. Two synthetic time series were created, one where respiration and aeration were independent of temperature and a second where respiration and aeration were affected by temperature according to the modified Arrhenius relationship. With these two synthetic time series, we again recovered the respiration and aeration input parameters using the night- time regression method and compared those recovered parameters with the input parameters. Because the simulations were conducted with parameters that were known, the values recovered using the night-time regression method (i.e post-simulation) could be compared with parameters driving the simulation (i.e. pre-simulation input values). For values based on data, we found a strong correlation between the aeration constant and respiration for both rivers. For the synthetic time series, no such correlation was found, either with the temperature independent or temperature dependent time series. The night-time regression method also recovered perfectly the input parameters, so the correlation was not brought about as a result of implementing the method itself. We are currently investigating the cause of the correlation.

  18. Volatile emissions during storing of green food waste under different aeration conditions.

    PubMed

    Agapiou, A; Vamvakari, J P; Andrianopoulos, A; Pappa, A

    2016-05-01

    Controlled field experiments were carried out for monitoring the emissions of three plastic commercial household waste bins, which were adapted for studying the effect of aeration process in the evolved volatiles, during house storing of green food waste for 2 weeks, prior to collection. Three experimental scenarios were examined based on no aeration ("NA," closed commercial waste bin), diffusion-based aeration ("DA," closed commercial waste bin with tiny holes), and enforced aeration ("EA," closed commercial waste bin with tiny holes and enforced aeration). The monitoring of volatile organic compounds (VOCs) emitted from organic household kitchen waste was performed using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analysis. Portable sensors were also used for monitoring selected gases and parameters of environmental, bioprocess, and health interest (e.g., CO2, O2, H2S, CH4, NH3, % RH, waste temperatures). VOC emissions are strongly dependent on the waste material. The most frequent VOCs identified over the storing waste, showing over 50 % appearance in all examined samples, were terpenes (e.g., di-limonene, beta-myrcene, delta-3-carene, alpha-pinene, alpha-terpinolene, linalool, etc.), sulfides (dimethyl disulfide), aromatics (benzene, 1-methyl-2-(2-propenyl)), alkanes (e.g., decane, dodecane), ketones (2-propanone), esters (e.g., acetic acid ethyl ester, acetic acid methyl ester), and alcohols (e.g., 3-cyclohexen-1-ol, 4-methyl-1-(1-methylethyl)). The prominent role of terpenes in the "pre-compost" odor and especially that of di-limonene was highlighted. In all examined scenarios, the emitted volatiles were increased at raised temperatures and later decreased in time. Aeration of waste bins slightly affected the volatilization process resulting in higher profiles of VOCs; uniformity in the composition of VOCs was also noted. Slight modifications of commercial waste bins may favor the initiation of home composting.

  19. Performance evaluation of a aerated lagoon under summer and winter conditions

    SciTech Connect

    Surampalli, R.Y.; Ninaroon, S.; Banerji, S.K.

    1998-07-01

    A one-year study evaluated the performance of a full-scale aerated lagoon, located in the Midwest, under winter and summer conditions. The objective of this study was mainly to evaluate the affect of temperature on BOD{sub 5}, suspended solids, and ammonia nitrogen removal. Influent and effluent samples were collected, for one-year, from this aerated lagoon system. The collected (monthly grab) influent and effluent samples were analyzed for BOD{sub 5}, suspended solids, ammonia nitrogen, organic nitrogen, nitrite nitrogen, and nitrate nitrogen. In addition, samples were also analyzed for total phosphorus, total alkalinity, dissolved oxygen, pH, E. Coli, fecal coliforms and temperature.

  20. Pathways of nitrobenzene degradation in horizontal subsurface flow constructed wetlands: Effect of intermittent aeration and glucose addition.

    PubMed

    Kirui, Wesley K; Wu, Shubiao; Kizito, Simon; Carvalho, Pedro N; Dong, Renjie

    2016-01-15

    Intermittent aeration and addition of glucose were applied to horizontal subsurface flow constructed wetlands in order to investigate the effect on pathways of nitrobenzene (NB) degradation and interactions with microbial nitrogen and sulphur transformations. The experiment was carried out in three phases A, B and C consisting of different NB loading and glucose dosing. For each phase, the effect of aeration was assessed by intermittently aerating one wetland and leaving one unaerated. Regardless of whether or not the wetland was aerated, at an influent NB concentration of 140 mg/L, both wetlands significantly reduced NB to less than 2 mg/L, a reduction efficiency of 98%. However, once the influent NB concentration was increased to 280 mg/L, the aerated wetland had a higher removal performance 82% compared to that of the unaerated wetland 71%. Addition of glucose further intensified the NB removal to 95% in the aerated wetlands and 92% in the unaerated. Aeration of wetlands enhanced NB degradation, but also resulted in higher NB volatilization of 6 mg m(-2) d(-1). The detected high concentration of sulphide 20-60 mg/L in the unaerated wetland gave a strong indication that NB may act as an electron donor to sulphate-reducing bacteria, but this should be further investigated. Aeration positively improved NB removal in constructed wetlands, but resulted in higher NB volatilization. Glucose addition induced co-metabolism to enhance NB degradation. PMID:26468606

  1. Pathways of nitrobenzene degradation in horizontal subsurface flow constructed wetlands: Effect of intermittent aeration and glucose addition.

    PubMed

    Kirui, Wesley K; Wu, Shubiao; Kizito, Simon; Carvalho, Pedro N; Dong, Renjie

    2016-01-15

    Intermittent aeration and addition of glucose were applied to horizontal subsurface flow constructed wetlands in order to investigate the effect on pathways of nitrobenzene (NB) degradation and interactions with microbial nitrogen and sulphur transformations. The experiment was carried out in three phases A, B and C consisting of different NB loading and glucose dosing. For each phase, the effect of aeration was assessed by intermittently aerating one wetland and leaving one unaerated. Regardless of whether or not the wetland was aerated, at an influent NB concentration of 140 mg/L, both wetlands significantly reduced NB to less than 2 mg/L, a reduction efficiency of 98%. However, once the influent NB concentration was increased to 280 mg/L, the aerated wetland had a higher removal performance 82% compared to that of the unaerated wetland 71%. Addition of glucose further intensified the NB removal to 95% in the aerated wetlands and 92% in the unaerated. Aeration of wetlands enhanced NB degradation, but also resulted in higher NB volatilization of 6 mg m(-2) d(-1). The detected high concentration of sulphide 20-60 mg/L in the unaerated wetland gave a strong indication that NB may act as an electron donor to sulphate-reducing bacteria, but this should be further investigated. Aeration positively improved NB removal in constructed wetlands, but resulted in higher NB volatilization. Glucose addition induced co-metabolism to enhance NB degradation.

  2. Functional linkage between N acquisition strategies and aeration capacities of hydrophytes for efficient oxygen consumption in roots.

    PubMed

    Nakamura, Motoka; Nakamura, Takatoshi; Tsuchiya, Takayoshi; Noguchi, Ko

    2013-02-01

    We evaluated the specific strategies of hydrophytes for root O(2) consumption in relation to N acquisition and investigated whether the strategies varied depending on the aeration capacity. Aeration capacity of roots is an important factor for determining hypoxia tolerance in plants. However, some hydrophytes possessing quite different aeration capacities often co-occur in wetlands, suggesting that root O(2) consumption also strongly affects hypoxia tolerance. We cultivated Phragmites australis with high aeration capacity and Zizania latifolia with low aeration capacity in hypoxic conditions with NH(4)(+) or NO(3)(-) treatment and compared the growth, N uptake, N assimilation and root respiration between the two species. In Z. latifolia grown with NH(4)(+) treatment, high N uptake activity and restrained root growth led to sufficient N acquisition and decrease in whole-root respiration rate. These characteristics consequently compensated for the low aeration capacity. In contrast, in P. australis, low N uptake activity was compensated by active root growth, but the whole-root respiration rate was high. This high root respiration rate was allowed by the high aeration capacity. The O(2) consumption-related traits of hydrophyte roots were closely correlated with N acquisition strategies, which consequently led to a compensational relationship with the root aeration capacity. It is likely that this functional linkage plays an important role as a core mechanism in the adaptation of plants to hypoxic soils.

  3. Functional linkage between N acquisition strategies and aeration capacities of hydrophytes for efficient oxygen consumption in roots.

    PubMed

    Nakamura, Motoka; Nakamura, Takatoshi; Tsuchiya, Takayoshi; Noguchi, Ko

    2013-02-01

    We evaluated the specific strategies of hydrophytes for root O(2) consumption in relation to N acquisition and investigated whether the strategies varied depending on the aeration capacity. Aeration capacity of roots is an important factor for determining hypoxia tolerance in plants. However, some hydrophytes possessing quite different aeration capacities often co-occur in wetlands, suggesting that root O(2) consumption also strongly affects hypoxia tolerance. We cultivated Phragmites australis with high aeration capacity and Zizania latifolia with low aeration capacity in hypoxic conditions with NH(4)(+) or NO(3)(-) treatment and compared the growth, N uptake, N assimilation and root respiration between the two species. In Z. latifolia grown with NH(4)(+) treatment, high N uptake activity and restrained root growth led to sufficient N acquisition and decrease in whole-root respiration rate. These characteristics consequently compensated for the low aeration capacity. In contrast, in P. australis, low N uptake activity was compensated by active root growth, but the whole-root respiration rate was high. This high root respiration rate was allowed by the high aeration capacity. The O(2) consumption-related traits of hydrophyte roots were closely correlated with N acquisition strategies, which consequently led to a compensational relationship with the root aeration capacity. It is likely that this functional linkage plays an important role as a core mechanism in the adaptation of plants to hypoxic soils. PMID:22575011

  4. The effect of aeration position on the spatial distribution and reduction of pollutants in the landfill stabilization process--a pilot scale study.

    PubMed

    Chai, Xiaoli; Hao, Yongxia; Shimaoka, Takayuki; Nakayama, Hirofumi; Komiya, Teppei; Zhao, Youcai

    2013-01-01

    Three pilot-scale simulators with different aeration systems were constructed to explore the effects of aeration position on the reduction of pollutants. The simulator with a bottom aeration system successfully distributed oxygen and efficiently inhibited methane production. A close relationship was found between the oxygen distribution and the removal of pollutants, especially that of nitrogen. The transition between nitrification and denitrification in the longitude direction of the simulator with a bottom aeration system contributed to nitrogen removal in aerobic conditions. This process can be defined as a new path for nitrogen removal in addition to simultaneous nitrification and denitrification. The concentration of NH4+ -N total nitrogen and total organic carbon dropped to 3, 78 and 204 mg L(-1), respectively, after 312 days of bottom aeration and to 514, 659 and 828 mg L(-1), respectively, after 312 days of top aeration. These results indicate that the bottom aeration system was more efficient for reducing pollutants than the top aeration system.

  5. Sorptivity of fly ash concretes

    SciTech Connect

    Gopalan, M.K.

    1996-08-01

    A factorial experiment was designed to measure the sorptivity of cement and fly ash concretes in order to compare the durability of fly ash concrete against the cement concrete. Sorptivity measurements based on the capillary movement of water was made on three grades of cement concrete and six grades of fly ash mixes. The effect of curing was also studied by treating the samples in two curving conditions. A functional relationship of sorptivity against the strength, curing condition and fly ash content has been presented. The results were useful to analyze the factors influencing the durability of cement and fly ash concretes and to explain why some of the previously reported findings were contradictory. Curing conditions have been found to be the most important factor that affected the durability properties of fly ash concrete. When proper curing was provided, a mix with 40% fly ash was found to reduce the sorptivity by 37%. Under inadequate curing the sorptivity was found to increase by 60%. The influence of curing on cement concrete was found to be of much less importance.

  6. Nitrification cessation and recovery in an aerated saturated vertical subsurface flow treatment wetland: Field studies and microscale biofilm modeling.

    PubMed

    Murphy, Clodagh; Rajabzadeh, Amin R; Weber, Kela P; Nivala, Jaime; Wallace, Scott D; Cooper, David J

    2016-06-01

    In aerated treatment wetlands, oxygen availability is not a limiting factor in sustaining a high level of nitrification in wastewater treatment. In the case of an air blower failure, nitrification would cease, potentially causing adverse effects to the nitrifying bacteria. A field trial was completed investigating nitrification loss when aeration is switched off, and the system recovery rate after the aeration is switched back on. Loss of dissolved oxygen was observed to be more rapid than loss of nitrification. Nitrate was observed in the effluent long after the aeration was switched off (48h+). A complementary modeling study predicted nitrate diffusion out of biofilm over a 48h period. After two weeks of no aeration in the established system, nitrification recovered within two days, whereas nitrification establishment in a new system was previously observed to require 20-45days. These results suggest that once established resident nitrifying microbial communities are quite robust. PMID:26967335

  7. Performance of organics and nitrogen removal in subsurface wastewater infiltration systems by intermittent aeration and shunt distributing wastewater.

    PubMed

    Pan, Jing; Yuan, Fang; Yu, Long; Huang, Linli; Fei, Hexin; Cheng, Fan; Zhang, Qi

    2016-07-01

    Organics and nitrogen removal in four subsurface wastewater infiltration systems (SWISs), named SWIS A (without intermittent aeration and shunt distributing wastewater), SWIS B (with intermittent aeration), SWIS C (with shunt distributing wastewater) and SWIS D (with intermittent aeration and shunt distributing wastewater) was investigated. High average removal rates of 92.3% for COD, 90.2% for NH4-N and 88.1% for TN were achieved simultaneously in SWIS D compared with SWIS A, B and C. The excellent TN removal of SWIS D was due to intermittent aeration provided sufficient oxygen for nitrification in upper matrix and the favorable anoxic or anaerobic environment for denitrification in subsequent matrix, and moreover, shunt distributing wastewater provided sufficient carbon source for denitrification process. The results indicated that intermittent artificial aeration combined with shunt distributing wastewater could achieve high organics and nitrogen removal in SWISs.

  8. High prevalence of qnr and aac(6')-Ib-cr genes in both water-borne environmental bacteria and clinical isolates of Citrobacter freundii in China.

    PubMed

    Zhang, Rong; Ichijo, Tomoaki; Huang, Yong-Lu; Cai, Jia-Chang; Zhou, Hong-Wei; Yamaguchi, Nobuyasu; Nasu, Masao; Chen, Gong-Xiang

    2012-01-01

    We investigated the prevalence of qnr and aac(6')-Ib-cr genes in water-borne environmental bacteria and in clinical isolates of Enterobacteriaceae, as well as the subtypes of qnr. Environmental bacteria were isolated from surface water samples obtained from 10 different locations in Hangzhou City, and clinical isolates of Citrobacter freundii were isolated from several hospitals in four cities in China. qnrA, qnrB, qnrS, and aac(6')-Ib-cr genes were screened using PCR, and the genotypes were analyzed by DNA sequencing. Ten of the 78 Gram-negative bacilli isolated from water samples were C. freundii and 80% of these isolates carried the qnrB gene. qnrS1 and aac(6')-Ib-cr genes were detected in two Escherichia coli isolates and qnrS2 was detected in one species, Aeromonas punctata. The qnr and aac(6')-Ib-cr genes were present in 75 (72.8%) and 12 (11.6%) of 103 clinical isolates of C. freundii, respectively. Of the clinical C. freundii isolates with the qnr gene, 65 isolates (63.1%) carried qnrB, but only three (2.9%) and one (1.0%) carried qnrA1 and qnrS2, respectively, while five isolates carried both qnrA1 and qnrB, and one isolate carried both qnrS1 and qnrB. The qnrB9 gene was the dominant qnrB subtype, followed by qnrB8 and qnrB6. Southern hybridization studies indicated that the qnr genes are located on different plasmids. Plasmids isolated from both environmental and clinical C. freundii isolates appeared to be homogenous.

  9. Vibrio cholerae InV117, a Class 1 Integron Harboring aac(6′)-Ib and blaCTX-M-2, Is Linked to Transposition Genes

    PubMed Central

    Soler Bistué, Alfonso J. C.; Martín, Fernando A.; Petroni, Alejandro; Faccone, Diego; Galas, Marcelo; Tolmasky, Marcelo E.; Zorreguieta, Angeles

    2006-01-01

    A ca. 150-kbp Vibrio cholerae O1 biotype El Tor plasmid includes blaCTX-M-2 and a variant of aac(6′)-Ib within InV117, an orf513-bearing class 1 integron. InV117 is linked to a tnp1696 module in which IRl carries an insertion of IS4321R. The complete structure could be a potential mobile element. PMID:16641475

  10. CuAAC click functionalization of azide-modified nanodiamond with a photoactivatable CO-releasing molecule (PhotoCORM) based on [Mn(CO)3(tpm)]+.

    PubMed

    Dördelmann, G; Meinhardt, Thomas; Sowik, Thomas; Krueger, Anke; Schatzschneider, Ulrich

    2012-12-01

    The copper-catalyzed 1,3-dipolar azide-alkyne cycloaddition (CuAAC) was used for the first time to attach a biologically active carbon monoxide delivery agent to modified nanodiamond (ND) as a highly biocompatible carrier. The [Mn(CO)(3)(tpm)](+) photoactivatable CO-releasing molecule (PhotoCORM) on the surface retained the carbon monoxide release properties of the parent compound as shown with the myoglobin assay.

  11. Testing of concrete by laser ablation

    DOEpatents

    Flesher, D.J.; Becker, D.L.; Beem, W.L.; Berry, T.C.; Cannon, N.S.

    1997-01-07

    A method is disclosed for testing concrete in a structure in situ, by: directing a succession of pulses of laser radiation at a point on the structure so that each pulse effects removal of a quantity of concrete and transfers energy to the concrete; detecting a characteristic of energy which has been transferred to the concrete; determining, separately from the detecting step, the total quantity of concrete removed by the succession of pulses; and calculating a property of the concrete on the basis of the detected energy characteristic and the determined total quantity of concrete removed. 1 fig.

  12. Testing of concrete by laser ablation

    DOEpatents

    Flesher, Dann J.; Becker, David L.; Beem, William L.; Berry, Tommy C.; Cannon, N. Scott

    1997-01-01

    A method of testing concrete in a structure in situ, by: directing a succession of pulses of laser radiation at a point on the structure so that each pulse effects removal of a quantity of concrete and transfers energy to the concrete; detecting a characteristic of energy which has been transferred to the concrete; determining, separately from the detecting step, the total quantity of concrete removed by the succession of pulses; and calculating a property of the concrete on the basis of the detected energy characteristic and the determined total quantity of concrete removed.

  13. Using the iPad to facilitate interaction between preschool children who use AAC and their peers.

    PubMed

    Therrien, Michelle C S; Light, Janice

    2016-09-01

    Social interaction is one of the key components of education, yet children with complex communication needs often face social isolation in the classroom, rarely interacting with same-age peers. This study investigated the impact of the provision of an iPad(®) (1) with an AAC app with visual scene displays and a dyadic turn taking training on the number of communicative turns taken by children with complex communication needs in interaction with same-age peers. Two preschool children with complex communication needs and six peers without disabilities participated in this research. A single-subject, multiple probe across partners design with one replication was used to evaluate the effectiveness of the intervention on the frequency of communicative turns expressed by the children with complex communication needs. Parents, teachers, speech-language pathologists, and the children participated in social validation measures. As a result of intervention, Participant 1 showed immediate gains in the frequency of symbolic communicative turns after the first training session across all three partners (average gains of 30-46 symbolic communicative turns per 10-min session across peer partners). Participant 2 showed some initial gains, but they were not maintained over time (average gains of 11-24 turns across partners). Classroom implications and future research directions are discussed. PMID:27414808

  14. Synthesis, antimicrobial activity, and membrane permeabilizing properties of C-terminally modified nisin conjugates accessed by CuAAC.

    PubMed

    Slootweg, Jack C; van der Wal, Steffen; Quarles van Ufford, H C; Breukink, Eefjan; Liskamp, Rob M J; Rijkers, Dirk T S

    2013-12-18

    Functionalization of the lantibiotic nisin with fluorescent reporter molecules is highly important for the understanding of its mode of action as a potent antimicrobial peptide. In addition to this, multimerization of nisin to obtain multivalent peptide constructs and conjugation of nisin to bioactive molecules or grafting it on surfaces can be attractive methods for interference with bacterial growth. Here, we report a convenient method for the synthesis of such nisin conjugates and show that these nisin derivatives retain both their antimicrobial activity and their membrane permeabilizing properties. The synthesis is based on the Cu(I)-catalyzed alkyne-azide cycloaddition reaction (CuAAC) as a bioorthogonal ligation method for large and unprotected peptides in which nisin was C-terminally modified with propargylamine and subsequently efficiently conjugated to a series of functionalized azides. Two fluorescently labeled nisin conjugates together with a dimeric nisin construct were prepared while membrane insertion as well as antimicrobial activity were unaffected by these modifications. This study shows that C-terminal modification of nisin does not deteriorate biological activity in sharp contrast to N-terminal modification and therefore C-terminally modified nisin analogues are valuable tools to study the antibacterial mode of action of nisin. Furthermore, the ability to use stoichiometric amounts of the azide containing molecule opens up possibilities for surface tethering and more complex multivalent structures.

  15. Silver-catalysed azide–alkyne cycloaddition (AgAAC): assessing the mechanism by density functional theory calculations

    PubMed Central

    Chandrasekhar, K.; Killi, Sunil Kumar; Pramanik, Sumit Kumar; Uttam, Pal; Sen, Sudeshna; Maiti, Nakul Chandra

    2016-01-01

    ‘Click reactions’ are the copper catalysed dipolar cycloaddition reaction of azides and alkynes to incorporate nitrogens into a cyclic hydrocarbon scaffold forming a triazole ring. Owing to its efficiency and versatility, this reaction and the products, triazole-containing heterocycles, have immense importance in medicinal chemistry. Copper is the only known catalyst to carry out this reaction, the mechanism of which remains unclear. We report here that the ‘click reactions’ can also be catalysed by silver halides in non-aqueous medium. It constitutes an alternative to the well-known CuAAC click reaction. The yield of the reaction varies on the type of counter ion present in the silver salt. This reaction exhibits significant features, such as high regioselectivity, mild reaction conditions, easy availability of substrates and reasonably good yields. In this communication, the findings of a new catalyst along with the effect of solvent and counter ions will help to decipher the still obscure mechanism of this important reaction. PMID:27703683

  16. Participation and Enjoyment in Play with a Robot between Children with Cerebral Palsy who use AAC and their Peers.

    PubMed

    Ferm, Ulrika M; Claesson, Britt K; Ottesjö, Cajsa; Ericsson, Stina

    2015-06-01

    This study explores children with complex communication needs, their peers and adult support persons in play with the talking and moving robot LekBot. Two triads were filmed playing with LekBot at pre-school. LekBot was developed to facilitate independent and enjoyable play on equal terms for children with significant communication disabilities and their peers. Using Conversation Analysis, participatory symmetry and enjoyment were investigated in relation to spoken and gestural communication, embodied stance, gaze, and affective display. Data originated from three video-recorded sessions that were approximately 2 hours long. Four different interaction situations were identified and explored: Participatory Asymmetry, Adult Facilitation, Greater Participatory Symmetry and Creativity, and Turn-taking and Enjoyable Play with LekBot. Neither participatory symmetry nor enjoyment were easily achieved in the play sessions and may require considerable effort, including adult involvement, but creative, spontaneous and highly enjoyable play, correlating with participatory symmetry to various degrees, was observed in a few instances. The findings are discussed with regard to play, AAC and the future development of robots to facilitate play.

  17. Participation and Enjoyment in Play with a Robot between Children with Cerebral Palsy who use AAC and their Peers.

    PubMed

    Ferm, Ulrika M; Claesson, Britt K; Ottesjö, Cajsa; Ericsson, Stina

    2015-06-01

    This study explores children with complex communication needs, their peers and adult support persons in play with the talking and moving robot LekBot. Two triads were filmed playing with LekBot at pre-school. LekBot was developed to facilitate independent and enjoyable play on equal terms for children with significant communication disabilities and their peers. Using Conversation Analysis, participatory symmetry and enjoyment were investigated in relation to spoken and gestural communication, embodied stance, gaze, and affective display. Data originated from three video-recorded sessions that were approximately 2 hours long. Four different interaction situations were identified and explored: Participatory Asymmetry, Adult Facilitation, Greater Participatory Symmetry and Creativity, and Turn-taking and Enjoyable Play with LekBot. Neither participatory symmetry nor enjoyment were easily achieved in the play sessions and may require considerable effort, including adult involvement, but creative, spontaneous and highly enjoyable play, correlating with participatory symmetry to various degrees, was observed in a few instances. The findings are discussed with regard to play, AAC and the future development of robots to facilitate play. PMID:25921358

  18. N400 brain responses to spoken phrases paired with photographs of scenes: implications for visual scene displays in AAC systems.

    PubMed

    Wilkinson, Krista M; Stutzman, Allyson; Seisler, Andrea

    2015-03-01

    Augmentative and alternative communication (AAC) systems are often implemented for individuals whose speech cannot meet their full communication needs. One type of aided display is called a Visual Scene Display (VSD). VSDs consist of integrated scenes (such as photographs) in which language concepts are embedded. Often, the representations of concepts on VSDs are perceptually similar to their referents. Given this physical resemblance, one may ask how well VSDs support development of symbolic functioning. We used brain imaging techniques to examine whether matches and mismatches between the content of spoken messages and photographic images of scenes evoke neural activity similar to activity that occurs to spoken or written words. Electroencephalography (EEG) was recorded from 15 college students who were shown photographs paired with spoken phrases that were either matched or mismatched to the concepts embedded within each photograph. Of interest was the N400 component, a negative deflecting wave 400 ms post-stimulus that is considered to be an index of semantic functioning. An N400 response in the mismatched condition (but not the matched) would replicate brain responses to traditional linguistic symbols. An N400 was found, exclusively in the mismatched condition, suggesting that mismatches between spoken messages and VSD-type representations set the stage for the N400 in ways similar to traditional linguistic symbols.

  19. Synthesis, antimicrobial activity, and membrane permeabilizing properties of C-terminally modified nisin conjugates accessed by CuAAC.

    PubMed

    Slootweg, Jack C; van der Wal, Steffen; Quarles van Ufford, H C; Breukink, Eefjan; Liskamp, Rob M J; Rijkers, Dirk T S

    2013-12-18

    Functionalization of the lantibiotic nisin with fluorescent reporter molecules is highly important for the understanding of its mode of action as a potent antimicrobial peptide. In addition to this, multimerization of nisin to obtain multivalent peptide constructs and conjugation of nisin to bioactive molecules or grafting it on surfaces can be attractive methods for interference with bacterial growth. Here, we report a convenient method for the synthesis of such nisin conjugates and show that these nisin derivatives retain both their antimicrobial activity and their membrane permeabilizing properties. The synthesis is based on the Cu(I)-catalyzed alkyne-azide cycloaddition reaction (CuAAC) as a bioorthogonal ligation method for large and unprotected peptides in which nisin was C-terminally modified with propargylamine and subsequently efficiently conjugated to a series of functionalized azides. Two fluorescently labeled nisin conjugates together with a dimeric nisin construct were prepared while membrane insertion as well as antimicrobial activity were unaffected by these modifications. This study shows that C-terminal modification of nisin does not deteriorate biological activity in sharp contrast to N-terminal modification and therefore C-terminally modified nisin analogues are valuable tools to study the antibacterial mode of action of nisin. Furthermore, the ability to use stoichiometric amounts of the azide containing molecule opens up possibilities for surface tethering and more complex multivalent structures. PMID:24266643

  20. Domain Dissection and Characterization of the Aminoglycoside Resistance Enzyme ANT(3″)-Ii/AAC(6′)-IId from Serratia marcescens

    PubMed Central

    Green, Keith D.; Garneau-Tsodikova, Sylvie

    2013-01-01

    Aminoglycosides (AGs) are broad-spectrum antibiotics whose constant use and presence in growth environment has led bacteria to develop resistance mechanisms to aid in their survival. A common mechanism of resistance to AGs is their chemical modification (nucleotidylation, phosphorylation, or acetylation) by AG-modifying enzymes (AMEs). Through evolution, fusion of two AME-encoding genes has resulted in bifunctional enzymes with broader spectrum of activity. Serratia marcescens, a human enteropathogen, contains such a bifunctional enzyme, ANT(3″)-Ii/AAC(6′)-IId. To gain insight into the role, effect, and importance of the union of ANT(3″)-Ii and AAC(6′)-IId in this bifunctional enzyme, we separated the two domains and compared their activity to that of the full-length enzyme. We performed a thorough comparison of the substrate and cosubstrate profiles as well as kinetic characterization of the bifunctional ANT(3″)-Ii/AAC(6′)-IId and its individually expressed components. PMID:23485681

  1. Cysteine as a Monothiol Reducing Agent to Prevent Copper-Mediated Oxidation of Interferon Beta During PEGylation by CuAAC.

    PubMed

    Nairn, Natalie W; Bariola, Pauline A; Graddis, Thomas J; VanBrunt, Michael Pete; Wang, Aijun; Li, Gary; Grabstein, Kenneth

    2015-10-21

    Bioconjugation by copper-catalyzed azide-alkyne cycloaddition (CuAAC) provides a powerful means to produce site-specifically modified proteins. However, the use of a copper catalyst brings about the possible generation of reactive oxygen species that could cause degradation of vulnerable amino acid residues. We investigated whether PEGylation by CuAAC caused any modifications to the therapeutic protein interferon beta-1b, which was produced via global amino acid substitution with azidohomo-alanine at the N-terminus and contains no methionine residues. Using previously reported reaction conditions, LC-MS peptide mapping detected +32 Da and +48 Da oxidation modifications of tryptic peptides 28-33 (LEYCLK) and 137-147 (EYSHCAWTIVR) in the protein post-PEGylation. The oxidative degradation increased with reaction time, whereas reducing the copper concentration slowed the PEGylation rate as well as the oxidation rate. Replacing dithiothreitol (DTT) with any of five different monothiol reducing agents in anaerobic conditions allowed efficient PEGylation in 2-4 h and abrogated oxidative degradation. Free cysteine provided reproducible reaction results as a reducing agent in this system and has been successfully applied to other protein conjugations. Monothiol reducing agents, such as cysteine, may be useful tools as protective reducing agents for CuAAC in some bioconjugation systems. PMID:26439457

  2. Treatment of landfill leachate using an aerated, horizontal subsurface-flow constructed wetland.

    PubMed

    Nivala, J; Hoos, M B; Cross, C; Wallace, S; Parkin, G

    2007-07-15

    A pilot-scale subsurface-flow constructed wetland was installed at the Jones County Municipal Landfill, near Anamosa, Iowa, in August 1999 to demonstrate the use of constructed wetlands as a viable low-cost treatment option for leachate generated at small landfills. The system was equipped with a patented wetland aeration process to aid in removal of organic matter and ammonia nitrogen. The high iron content of the leachate caused the aeration system to cease 2 years into operation. Upon the installation of a pretreatment chamber for iron removal and a new aeration system, treatment efficiencies dramatically improved. Seasonal performance with and without aeration is reported for 5-day biochemical oxygen demand (BOD(5)), chemical oxygen demand (COD), ammonia nitrogen (NH(4)-N), and nitrate nitrogen (NO(3)-N). Since winter air temperatures in Iowa can be very cold, a layer of mulch insulation was installed on top of the wetland bed to keep the system from freezing. When the insulation layer was properly maintained (either through sufficient litterfall or replenishing the mulch layer), the wetland sustained air temperatures of as low as -26 degrees C without freezing problems.

  3. Improvement of anaerobic digester performance by wastewater recirculation through an aerated membrane.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine wastewater from an anaerobic digester was recirculated through a silicone hose located in an external aeration chamber to determine its effect on wastewater malodorants and biogas composition. The silicone hose acted as a semipermeable membrane for the passage of small molecules. In the first...

  4. Effect of agitation and aeration on the citric acid production by Yarrowia lipolytica grown on glycerol.

    PubMed

    Rywińska, Anita; Musiał, Izabela; Rymowicz, Waldemar; Zarowska, Barbara; Boruczkowski, Tomasz

    2012-01-01

    The effects of agitation rates from 400 to 900 rpm and aeration rates ranging from 0.18 to 0.6 vvm on biomass and citric acid production on glycerol media by acetate-negative mutants of Yarrowia lipolytica, Wratislavia 1.31 and Wratislavia AWG7, in batch culture were studied. The agitation rates of 800 and 900 rpm (at a constant aeration rate of 0.36 vvm) and aeration rates within the range of 0.24-0.48 vvm (at a constant agitation rate of 800 rpm), which generated dissolved oxygen concentration (DO) higher than 40%, were found the best for citric acid biosynthesis from glycerol. An increase in agitation rate (higher than 800 rpm) and aeration rate (higher than 0.36 vvm) had no impact on DO and citric acid production. The highest citric acid concentration (92.8 g/L) and yield (0.63 g/g) were obtained with Wratislavia 1.31 strain at 0.24 vvm. The highest volumetric citric acid production rate (1.15 g/Lh) and specific citric acid production rate (0.071 g/gh) were reached at 0.48 vvm.

  5. 72. (Credit LSU) Aerator in settling basin south of McNeil ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    72. (Credit LSU) Aerator in settling basin south of McNeil Pumping Station c1907. (Louisiana State University in Shreveport Archives, post card collection) - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  6. Flow, aeration, and carbon dioxide transfer rates for airlifts used in recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Airlift pumping systems reduce the electrical costs of moving water in a recirculating aquaculture system and can be concurrently designed to aerate water and remove carbon dioxide. This study determined the water flow, oxygen transfer, and CO2 removal rates for water using airlift technology in a 1...

  7. Evaluation of cost-effective aeration technology solutions to address total trihalomethane (TTHM) compliance

    EPA Science Inventory

    The primary objective of this project was to evaluate cost-effective aeration technology solutions to address TTHM compliance at a water treatment plant clearwell. The project team worked closely with EPA Region 6 and the EPA Office of Research and Development (ORD) to identify a...

  8. [Technological characteristics of bioreactor landfill with aeration in the upper layer].

    PubMed

    Tian, Ying; Wang, Shen; Xu, Qi-Yong

    2014-11-01

    In order to study the effects of upper-layer aerobic pretreatment in bioreactors on refuse degradation, leachate condition and methane production, two simulated columns were constructed, including traditional anaerobic bioreactor A1 and hybrid bioreactor C1 with aeration pretreatment in the upper layer. Results indicated that A1 was seriously inhibited by the accumulation of volatile fatty acids (VFA) with nearly no methane production and slower settlements. At the end of operations, refuse in A1 only deposited 5.4 cm which was less than half of that in C1. And up to 70 000 mg x L(-1) COD and 30 000 mg x L(-1) VFA could be monitored in the leachate. On the contrary, aerobic pretreatment effectively improved the removal of high VFA concentrations and remarkably accelerated the degradation rate. In bioreactor C1, COD and VFA concentrations were reduced to less than 14000 mg x L(-1) and 8900 mg x L(-1) at the end of the experiment, respectively. And about 61 976 mL methane gases were produced since aeration ceased on day 60 with its methane recovery efficiency rising to over 95%. However, the performance of hybrid bioreactors was still closely related to its operation conditions, such as aeration supply and leachate recirculation. Therefore, in order to guarantee better performance, appropriate aeration and leachate operations need to be provided.

  9. Processes to improve energy efficiency during pumping and aeration of recirculating water in circular tank systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conventional gas transfer technologies for aquaculture systems occupy a large amount of space, require considerable capital investment, and can contribute to high electricity demand. In addition, diffused aeration in a circular tank can interfere with the hydrodynamics of water rotation and the spee...

  10. Combination of methoprene and controlled aeration to manage insects in stored wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The insect growth regulator methoprene, in the commercial formulation Diacon II®, was applied to wheat stored in small bins either alone or in combination with controlled aeration of the bins to lower grain temperature for insect pest management of stored wheat. Grain temperatures and monitored and ...

  11. Gas transfer rates from airlifts used for concurrent aeration, carbon dioxide stripping, and recirculation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Airlifts simplify recirculating aquaculture systems and can potentially reduce capital costs and minimize maintenance issues. Airlifts have the ability to move and aerate water as well as degass the water of any carbon dioxide. This study evaluated the oxygen transfer and carbon dioxide removal abil...

  12. Effects of aeration intensity on formation of phenol-fed aerobic granules and extracellular polymeric substances.

    PubMed

    Adav, Sunil S; Lee, Duu-Jong; Lai, J Y

    2007-11-01

    Effect of air aeration intensities on granule formation and extracellular polymeric substances content in three identical sequential batch reactors were investigated. The excitation-emission-matrix spectra and multiple staining and confocal laser scanning microscope revealed proteins, polysaccharides, lipids, and humic substances in the sludge and granule samples. Seed sludge flocs were compacted at low aeration rate, with produced extracellular polymeric substances of 50.2-76.7 mg g(-1) of proteins, 50.2-77.3 mg g(-1) carbohydrates and 74 mg g(-1) humic substances. High aeration rate accelerated formation of 1.0-1.5 mm granules with smooth outer surface. The corresponding quantities of extracellular polymeric substances were 309-537 mg g(-1) of proteins, 61-109 mg g(-1) carbohydrates, 49-92 mg g(-1) humic substances, and 49-68 mg g(-1) lipids. Intermediate aeration rate produced 3.0-3.5 mm granules with surface filaments. Reactor failure occurred with overgrowth of filaments, probably owing to the deficiency of nutrient in liquid phase. No correlation was noted between extracellular polymeric substances composition and the proliferation of filamentous microorganisms on granule surface.

  13. EVALUATING THE COSTS OF PACKED-TOWER AERATION AND GAC FOR CONTROLLING SELECTED ORGANICS

    EPA Science Inventory

    This article focuses on a preliminary cost analysis that compares liquid-phase granular activated carbon (GAC) treatment with packed-tower aeration (PTA) treatment, with and without air emissions control. The sensitivity of cost to design and operating variables is also discussed...

  14. Integral parameters for characterizing water, energy, and aeration properties of soilless plant growth media

    NASA Astrophysics Data System (ADS)

    Chamindu Deepagoda, T. K. K.; Chen Lopez, Jose Choc; Møldrup, Per; de Jonge, Lis Wollesen; Tuller, Markus

    2013-10-01

    Over the last decade there has been a significant shift in global agricultural practice. Because the rapid increase of human population poses unprecedented challenges to production of an adequate and economically feasible food supply for undernourished populations, soilless greenhouse production systems are regaining increased worldwide attention. The optimal control of water availability and aeration is an essential prerequisite to successfully operate plant growth systems with soilless substrates such as aggregated foamed glass, perlite, rockwool, coconut coir, or mixtures thereof. While there are considerable empirical and theoretical efforts devoted to characterize water retention and aeration substrate properties, a holistic, physically-based approach considering water retention and aeration concurrently is lacking. In this study, the previously developed concept of integral water storage and energy was expanded to dual-porosity substrates and an analog integral oxygen diffusivity parameter was introduced to simultaneously characterize aeration properties of four common soilless greenhouse growth media. Integral parameters were derived for greenhouse crops in general, as well as for tomatoes. The integral approach provided important insights for irrigation management and for potential optimization of substrate properties. Furthermore, an observed relationship between the integral parameters for water availability and oxygen diffusivity can be potentially applied for the design of advanced irrigation and management strategies to ensure stress-free growth conditions, while conserving water resources.

  15. Effect of the aerated structure on selected properties of freeze-dried hydrocolloid gels

    NASA Astrophysics Data System (ADS)

    Ciurzyńska, Agnieszka; Lenart, Andrzej

    2016-01-01

    The ability to create diverse structures and studies on the effect of the aerated structure on selected properties with the use of freeze-dried gels may provide knowledge about the properties of dried foods. Such gels can be a basis for obtaining innovative food products. For the gel preparation, 3 types of hydrocolloids were used: low-methoxyl pectin, a mixture of xanthan gum and locust-bean gum, and a mixture of xanthan gum and guar gum. Gels were aerated for 3 and 7 min, frozen at a temperature of -45°C 2 h-1, and freeze-dried at a temperature of 30°C. For the samples obtained, structure, porosity, shrinkage, rehydration, and colour were investigated. It was shown that the type of the hydrocolloid and aeration time influence the structure of freeze-dried gels, which determines such properties of samples as porosity, shrinkage, density, rehydration, and colour. The bigger pores of low-methoxyl pectin gels undergo rehydration in the highest degree. The delicate and aerated structure of gels with the mixture of xanthan gum and locust-bean gum was damaged during freeze-drying and shrinkage exhibited the highest value. Small pores of samples with the mixture of xanthan gum and guar gum were responsible for the lower rehydration properties, but the highest porosity value contributed to the highest lightness value.

  16. Optimization of micro-aeration intensity in acidogenic reactor of a two-phase anaerobic digester treating food waste

    SciTech Connect

    Xu, Suyun; Selvam, Ammaiyappan; Wong, Jonathan W.C.

    2014-02-15

    Highlights: • Effect of micro-aeration on acidogenesis and hydrolysis of food waste was investigated. • Micro-aeration at 258 L-air/kg TS/d increased the VFAs production 3-fold. • High aeration leads to loss of substrate through microbial biomass and respiration. • Optimum aeration increased methane recovery while high aeration intensity reduced methane yield. - Abstract: Micro-aeration is known to promote the activities of hydrolytic exo-enzymes and used as a strategy to improve the hydrolysis of particulate substrate. The effect of different micro-aeration rates, 0, 129, 258, and 387 L-air/kg TS/d (denoted as LBR-AN, LBR-6h, LBR-3h and LBR-2h, respectively) on the solubilization of food waste was evaluated at 35 °C in four leach bed reactors (LBR) coupled with methanogenic upflow anaerobic sludge blanket (UASB) reactor. Results indicate that the intensity of micro-aeration influenced the hydrolysis and methane yield. Adequate micro-aeration intensity in LBR-3h and LBR-2h significantly enhanced the carbohydrate and protein hydrolysis by 21–27% and 38–64% respectively. Due to the accelerated acidogenesis, more than 3-fold of acetic acid and butyric acid were produced in LBR-3h as compared to the anaerobic treatment LBR-AN resulting in the maximum methane yield of 0.27 L CH{sub 4}/g VS{sub added} in the UASB. The performance of LBR-6h with inadequate aeration was similar to that of LBR-AN with a comparable hydrolysis degree. Nevertheless, higher aeration intensity in LBR-2h was also unfavorable for methane yield due to significant biomass generation and CO{sub 2} respiration of up to 18.5% and 32.8% of the total soluble hydrolysate, respectively. To conclude, appropriate micro-aeration rate can promote the hydrolysis of solid organic waste and methane yield without undesirable carbon loss and an aeration intensity of 258 L-air/kg TS/d is recommended for acidogenic LBR treating food waste.

  17. Impact of intermittent aerations on leachate quality and greenhouse gas reduction in the aerobic-anaerobic landfill method.

    PubMed

    Nag, Mitali; Shimaoka, Takayuki; Komiya, Teppei

    2016-09-01

    The aerobic-anaerobic landfill method (AALM) is a novel approach in solid waste management that could shorten the landfill post-closure period and minimize the environmental loads. In this study, the aerobic-anaerobic landfill method was evaluated by using intermittent aeration. In addition, the nitrification-denitrification process was assessed as a means of reducing the emission of greenhouse gases (GHGs) and improving the leachate quality during the degradation of the organic solid waste. The leachate quality and the gas composition in each of the reactors were measured during the experimental period (408days). The aeration process entailed the injection of air into plexiglass cylinders (200cm height×10 cm diameter), filled with fresh organic solid waste collected from a composting plant. Different aeration routines were applied, namely, continuous aeration (aerobic reactor A), aeration for three days/week (aerobic-anaerobic reactor B), aeration for 6h/day (aerobic-anaerobic reactor C), and no aeration (non-aerated reactor D). It was found that aerobic reactor A produced the best results in terms of reduction of GHGs and improvement of the leachate quality. The aerobic-anaerobic reactor C was found to be more effective than reactor B in respect of both the emission of GHGs and the leachate quality; moreover, compared with aerobic reactor A, energy costs were reduced by operating this reactor. The transition period phenomenon was investigated during an intensive seven-day experiment conducted on the discharged leachate obtained from aerobic-anaerobic reactors B and C. The experiment concerned the differences in the composition of the gas during the aeration and the non-aeration periods. It was found that the transition period between the aeration and non-aeration cycles, which followed the simultaneous nitrification-denitrification had a considerable effect on the leachate quality of both the reactors. The results indicated that AALM has the potential to reduce

  18. Impact of intermittent aerations on leachate quality and greenhouse gas reduction in the aerobic-anaerobic landfill method.

    PubMed

    Nag, Mitali; Shimaoka, Takayuki; Komiya, Teppei

    2016-09-01

    The aerobic-anaerobic landfill method (AALM) is a novel approach in solid waste management that could shorten the landfill post-closure period and minimize the environmental loads. In this study, the aerobic-anaerobic landfill method was evaluated by using intermittent aeration. In addition, the nitrification-denitrification process was assessed as a means of reducing the emission of greenhouse gases (GHGs) and improving the leachate quality during the degradation of the organic solid waste. The leachate quality and the gas composition in each of the reactors were measured during the experimental period (408days). The aeration process entailed the injection of air into plexiglass cylinders (200cm height×10 cm diameter), filled with fresh organic solid waste collected from a composting plant. Different aeration routines were applied, namely, continuous aeration (aerobic reactor A), aeration for three days/week (aerobic-anaerobic reactor B), aeration for 6h/day (aerobic-anaerobic reactor C), and no aeration (non-aerated reactor D). It was found that aerobic reactor A produced the best results in terms of reduction of GHGs and improvement of the leachate quality. The aerobic-anaerobic reactor C was found to be more effective than reactor B in respect of both the emission of GHGs and the leachate quality; moreover, compared with aerobic reactor A, energy costs were reduced by operating this reactor. The transition period phenomenon was investigated during an intensive seven-day experiment conducted on the discharged leachate obtained from aerobic-anaerobic reactors B and C. The experiment concerned the differences in the composition of the gas during the aeration and the non-aeration periods. It was found that the transition period between the aeration and non-aeration cycles, which followed the simultaneous nitrification-denitrification had a considerable effect on the leachate quality of both the reactors. The results indicated that AALM has the potential to reduce

  19. Effects of fertilizer and pesticides on concrete

    SciTech Connect

    Broder, M.F.; Nguyen, D.T.; Harner, A.L.

    1994-12-31

    Concrete is the most common material of construction for secondary containment of fertilizers and pesticides because of its relative low cost and structural properties. Concrete, however, is porous to some products it is designed to contain and is subject to corrosion. In this paper, concrete deterioration mechanisms and corrosion resistant concrete formulation are discussed, as well as exposure tests of various concrete mixes to some common liquid fertilizers and herbicides.

  20. Electrically conductive polymer concrete coatings

    DOEpatents

    Fontana, J.J.; Elling, D.; Reams, W.

    1990-03-13

    A sprayable electrically conductive polymer concrete coating for vertical d overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt % calcined coke breeze, 40 wt % vinyl ester with 3.5 wt % modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag.

  1. Electrically conductive polymer concrete coatings

    DOEpatents

    Fontana, J.J.; Elling, D.; Reams, W.

    1988-05-26

    A sprayable electrically conductive polymer concrete coating for vertical and overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt% calcined coke breeze, 40 wt% vinyl ester resin with 3.5 wt% modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag. 4 tabs.

  2. Electrically conductive polymer concrete coatings

    DOEpatents

    Fontana, Jack J.; Elling, David; Reams, Walter

    1990-01-01

    A sprayable electrically conductive polymer concrete coating for vertical d overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt % calcined coke breeze, 40 wt % vinyl ester with 3.5 wt % modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag.

  3. Lipid accumulation and CO2 utilization of Nannochloropsis oculata in response to CO2 aeration.

    PubMed

    Chiu, Sheng-Yi; Kao, Chien-Ya; Tsai, Ming-Ta; Ong, Seow-Chin; Chen, Chiun-Hsun; Lin, Chih-Sheng

    2009-01-01

    In order to produce microalgal lipids that can be transformed to biodiesel fuel, effects of concentration of CO(2) aeration on the biomass production and lipid accumulation of Nannochloropsis oculata in a semicontinuous culture were investigated in this study. Lipid content of N. oculata cells at different growth phases was also explored. The results showed that the lipid accumulation from logarithmic phase to stationary phase of N. oculata NCTU-3 was significantly increased from 30.8% to 50.4%. In the microalgal cultures aerated with 2%, 5%, 10% and 15% CO(2), the maximal biomass and lipid productivity in the semicontinuous system were 0.480 and 0.142 g L(-1)d(-1) with 2% CO(2) aeration, respectively. Even the N. oculata NCTU-3 cultured in the semicontinuous system aerated with 15% CO(2), the biomass and lipid productivity could reach to 0.372 and 0.084 g L(-1)d(-1), respectively. In the comparison of productive efficiencies, the semicontinuous system was operated with two culture approaches over 12d. The biomass and lipid productivity of N. oculata NCTU-3 were 0.497 and 0.151 g L(-1)d(-1) in one-day replacement (half broth was replaced each day), and were 0.296 and 0.121 g L(-1)d(-1) in three-day replacement (three fifth broth was replaced every 3d), respectively. To optimize the condition for long-term biomass and lipid yield from N. oculata NCTU-3, this microalga was suggested to grow in the semicontinuous system aerated with 2% CO(2) and operated by one-day replacement. PMID:18722767

  4. Spatiotemporal Aeration and Lung Injury Patterns Are Influenced by the First Inflation Strategy at Birth.

    PubMed

    Tingay, David G; Rajapaksa, Anushi; Zonneveld, C Elroy; Black, Don; Perkins, Elizabeth J; Adler, Andy; Grychtol, Bartłomiej; Lavizzari, Anna; Frerichs, Inéz; Zahra, Valerie A; Davis, Peter G

    2016-02-01

    Ineffective aeration during the first inflations at birth creates regional aeration and ventilation defects, initiating injurious pathways. This study aimed to compare a sustained first inflation at birth or dynamic end-expiratory supported recruitment during tidal inflations against ventilation without intentional recruitment on gas exchange, lung mechanics, spatiotemporal regional aeration and tidal ventilation, and regional lung injury in preterm lambs. Lambs (127 ± 2 d gestation), instrumented at birth, were ventilated for 60 minutes from birth with either lung-protective positive pressure ventilation (control) or as per control after either an initial 30 seconds of 40 cm H2O sustained inflation (SI) or an initial stepwise end-expiratory pressure recruitment maneuver during tidal inflations (duration 180 s; open lung ventilation [OLV]). At study completion, molecular markers of lung injury were analyzed. The initial use of an OLV maneuver, but not SI, at birth resulted in improved lung compliance, oxygenation, end-expiratory lung volume, and reduced ventilatory needs compared with control, persisting throughout the study. These changes were due to more uniform inter- and intrasubject gravity-dependent spatiotemporal patterns of aeration (measured using electrical impedance tomography). Spatial distribution of tidal ventilation was more stable after either recruitment maneuver. All strategies caused regional lung injury patterns that mirrored associated regional volume states. Irrespective of strategy, spatiotemporal volume loss was consistently associated with up-regulation of early growth response-1 expression. Our results show that mechanical and molecular consequences of lung aeration at birth are not simply related to rapidity of fluid clearance; they are also related to spatiotemporal pressure-volume interactions within the lung during inflation and deflation.

  5. Combination of Methoprene and Controlled Aeration to Manage Insects in Stored Wheat.

    PubMed

    Liu, Samuel S; Arthur, Frank H; VanGundy, Douglas; Phillips, Thomas W

    2016-06-17

    A commercial formulation of the insect growth regulator methoprene was applied to wheat stored in small bins either alone or in combination with controlled aeration of the bins, to lower grain temperature for insect pest management of stored wheat. Grain temperatures were monitored and modified by a computer-controlled thermocouple system that also activated the aeration system at programmed set-points to move cool ambient air through the grain mass to lower grain temperature. Results from sampling insect populations in experimental storage bins along with laboratory mortality bioassays of insects placed on wheat taken from the bins over the course of the storage period showed that methoprene was very effective in controlling infestation by the externally-feeding stored grain insects Plodia interpunctella (Hübner), the Indian meal moth Tribolium castaneum (Herbst), the red flour beetle, Cryptolestes ferrugineus (Stephens), the rusty grain beetle, and also for the internal-feeding pest Rhyzopertha dominica( Fauvel), the lesser grain borer. Methoprene did not give good control of the internal-feeding pest Sitophilus oryzae (L.), the rice weevil. Aeration alone was somewhat effective in suppressing insect population development, while methoprene alone or when combined with aeration greatly enhanced insect control. Commercial grain grading for industry quality standards at the end of the storage period confirmed the impact of insect suppression on maintaining high quality of the stored wheat. This field experiment shows that methoprene combined with aeration to cool grain can be effective for pest management of stored wheat in the southern plains of the United States of America.

  6. [Effect of Aeration Strategies on Emissions of Nitrogenous Gases and Methane During Sludge Bio-Drying].

    PubMed

    Qi, Lu; Wei, Yuan-song; Zhang, Jun-ya; Zhao, Chen-yang; Cai, Xing; Zhang, Yuan-li; Shao, Chun-yan; Li, Hong-mei

    2016-01-15

    The data on nitrogen gas (NH3, N2O, NO) emissions during sludge bio-drying process in China is scarce, especially NO due to its unstable chemical property. In this study, effect of two aeration modes on emissions of methane and nitrogenous gas was compared during the continuous aerated turning pile sludge bio-drying process at full scale. In these two aeration strategies, the one currently used in the plant was set as the control, and the other was set as the test in which the aeration was used for oxygen supply, pile temperature control, and moisture removal in the start-up, middle and final stages, respectively. The results showed that the aeration strategy used in the test could not only obviously accelerate the rate of sludge drying (the moisture contents of the test and the control were 36.6% and 42% on day 11) , but also had a better drying performance (the final moisture contents of the test and the control were 33.6% and 37.6%, respectively) and decreased the ammonia cumulative emission by 5%, (ammonia cumulative emission of the test and the control were 208 mg x m(-3) and 219.8 mg x m(-3), respectively). Though a lower accumulated emission (eCO2) of greenhouse gas in the test at 3.61 kg x t(-1) was observed than that of the control (3.73 kg x t(-1) dry weight) , the cumulative emission of NO in the test at 1.9 g x m(-2) was 15. 9% higher than that of the control (1.6 g x m(-2)).

  7. Combination of Methoprene and Controlled Aeration to Manage Insects in Stored Wheat

    PubMed Central

    Liu, Samuel S.; Arthur, Frank H.; VanGundy, Douglas; Phillips, Thomas W.

    2016-01-01

    A commercial formulation of the insect growth regulator methoprene was applied to wheat stored in small bins either alone or in combination with controlled aeration of the bins, to lower grain temperature for insect pest management of stored wheat. Grain temperatures were monitored and modified by a computer-controlled thermocouple system that also activated the aeration system at programmed set-points to move cool ambient air through the grain mass to lower grain temperature. Results from sampling insect populations in experimental storage bins along with laboratory mortality bioassays of insects placed on wheat taken from the bins over the course of the storage period showed that methoprene was very effective in controlling infestation by the externally-feeding stored grain insects Plodia interpunctella (Hübner), the Indian meal moth Tribolium castaneum (Herbst), the red flour beetle, Cryptolestes ferrugineus (Stephens), the rusty grain beetle, and also for the internal-feeding pest Rhyzopertha dominica( Fauvel), the lesser grain borer. Methoprene did not give good control of the internal-feeding pest Sitophilus oryzae (L.), the rice weevil. Aeration alone was somewhat effective in suppressing insect population development, while methoprene alone or when combined with aeration greatly enhanced insect control. Commercial grain grading for industry quality standards at the end of the storage period confirmed the impact of insect suppression on maintaining high quality of the stored wheat. This field experiment shows that methoprene combined with aeration to cool grain can be effective for pest management of stored wheat in the southern plains of the United States of America. PMID:27322331

  8. Combination of Methoprene and Controlled Aeration to Manage Insects in Stored Wheat.

    PubMed

    Liu, Samuel S; Arthur, Frank H; VanGundy, Douglas; Phillips, Thomas W

    2016-01-01

    A commercial formulation of the insect growth regulator methoprene was applied to wheat stored in small bins either alone or in combination with controlled aeration of the bins, to lower grain temperature for insect pest management of stored wheat. Grain temperatures were monitored and modified by a computer-controlled thermocouple system that also activated the aeration system at programmed set-points to move cool ambient air through the grain mass to lower grain temperature. Results from sampling insect populations in experimental storage bins along with laboratory mortality bioassays of insects placed on wheat taken from the bins over the course of the storage period showed that methoprene was very effective in controlling infestation by the externally-feeding stored grain insects Plodia interpunctella (Hübner), the Indian meal moth Tribolium castaneum (Herbst), the red flour beetle, Cryptolestes ferrugineus (Stephens), the rusty grain beetle, and also for the internal-feeding pest Rhyzopertha dominica( Fauvel), the lesser grain borer. Methoprene did not give good control of the internal-feeding pest Sitophilus oryzae (L.), the rice weevil. Aeration alone was somewhat effective in suppressing insect population development, while methoprene alone or when combined with aeration greatly enhanced insect control. Commercial grain grading for industry quality standards at the end of the storage period confirmed the impact of insect suppression on maintaining high quality of the stored wheat. This field experiment shows that methoprene combined with aeration to cool grain can be effective for pest management of stored wheat in the southern plains of the United States of America. PMID:27322331

  9. Lipid accumulation and CO2 utilization of Nannochloropsis oculata in response to CO2 aeration.

    PubMed

    Chiu, Sheng-Yi; Kao, Chien-Ya; Tsai, Ming-Ta; Ong, Seow-Chin; Chen, Chiun-Hsun; Lin, Chih-Sheng

    2009-01-01

    In order to produce microalgal lipids that can be transformed to biodiesel fuel, effects of concentration of CO(2) aeration on the biomass production and lipid accumulation of Nannochloropsis oculata in a semicontinuous culture were investigated in this study. Lipid content of N. oculata cells at different growth phases was also explored. The results showed that the lipid accumulation from logarithmic phase to stationary phase of N. oculata NCTU-3 was significantly increased from 30.8% to 50.4%. In the microalgal cultures aerated with 2%, 5%, 10% and 15% CO(2), the maximal biomass and lipid productivity in the semicontinuous system were 0.480 and 0.142 g L(-1)d(-1) with 2% CO(2) aeration, respectively. Even the N. oculata NCTU-3 cultured in the semicontinuous system aerated with 15% CO(2), the biomass and lipid productivity could reach to 0.372 and 0.084 g L(-1)d(-1), respectively. In the comparison of productive efficiencies, the semicontinuous system was operated with two culture approaches over 12d. The biomass and lipid productivity of N. oculata NCTU-3 were 0.497 and 0.151 g L(-1)d(-1) in one-day replacement (half broth was replaced each day), and were 0.296 and 0.121 g L(-1)d(-1) in three-day replacement (three fifth broth was replaced every 3d), respectively. To optimize the condition for long-term biomass and lipid yield from N. oculata NCTU-3, this microalga was suggested to grow in the semicontinuous system aerated with 2% CO(2) and operated by one-day replacement.

  10. Protective coatings for concrete

    SciTech Connect

    NAGY, KATHRYN L.; CYGAN, RANDALL T.; BRINKER, C. JEFFREY; SELLINGER, ALAN

    2000-05-01

    The new two-layer protective coating developed for monuments constructed of limestone or marble was applied to highway cement and to tobermorite, a component of cement, and tested in batch dissolution tests. The goal was to determine the suitability of the protective coating in retarding the weathering rate of concrete construction. The two-layer coating consists of an inner layer of aminoethylaminopropylsilane (AEAPS) applied as a 25% solution in methanol and an outer layer of A2** sol-gel. In previous work, this product when applied to calcite powders, had resulted in a lowering of the rate of dissolution by a factor of ten and was shown through molecular modeling to bind strongly to the calcite surface, but not too strongly so as to accelerate dissolution. Batch dissolution tests at 22 C of coated and uncoated tobermorite (1.1 nm phase) and powdered cement from Gibson Blvd. in Albuquerque indicated that the coating exhibits some protective behavior, at least on short time scales. However, the data suggest that the outer layer of sol-gel dissolves in the high-pH environment of the closed system of cement plus water. Calculated binding configuration and energy of AEAPS to the tobermorite surface suggests that AEAPS is well-suited as the inner layer binder for protecting tobermorite.

  11. Becoming Reactive by Concretization

    NASA Technical Reports Server (NTRS)

    Prieditis, Armand; Janakiraman, Bhaskar

    1992-01-01

    One way to build a reactive system is to construct an action table indexed by the current situation or stimulus. The action table describes what course of action to pursue for each situation or stimulus. This paper describes an incremental approach to constructing the action table through achieving goals with a hierarchical search system. These hierarchies are generated with transformations called concretizations, which add constraints to a problem and which can reduce the search space. The basic idea is that an action for a state is looked up in the action table and executed whenever the action table has an entry for that state; otherwise, a path is found to the nearest (cost-wise in a graph with costweighted arcs) state that has a mappring from a state in the next highest hierarchy. For each state along the solution path, the successor state in the path is cached in the action table entry for that state. Without caching, the hierarchical search system can logarithmically reduce search. When the table is complete the system no longer searches: it simply reacts by proceeding to the state listed in the table for each state. Since the cached information is specific only to the nearest state in the next highest hierarchy and not the goal, inter-goal transfer of reactivity is possible. To illustrate our approach, we show how an implemented hierarchical search system can completely reactive.

  12. Intensified organics and nitrogen removal in the intermittent-aerated constructed wetland using a novel sludge-ceramsite as substrate.

    PubMed

    Wu, Haiming; Fan, Jinlin; Zhang, Jian; Ngo, Huu Hao; Guo, Wenshan; Liang, Shuang; Lv, Jialong; Lu, Shaoyong; Wu, Weizhong; Wu, Suqing

    2016-06-01

    In this study, a novel sludge-ceramsite was applied as main substrate in intermittent-aerated subsurface flow constructed wetlands (SSF CWs) for treating decentralized domestic wastewater, and intensified organics and nitrogen removal in different SSF CWs (with and without intermittent aeration, with and without sludge-ceramsite substrate) were evaluated. High removal of 97.2% COD, 98.9% NH4(+)-N and 85.8% TN were obtained simultaneously in the intermittent-aerated CW system using sludge-ceramsite substrate compared with non-aerated CWs. Moreover, results from fluorescence in situ hybridization (FISH) analysis revealed that the growth of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the intermittent-aerated CW system with sludge-ceramsite substrate was enhanced, thus indicating that the application of intermittent aeration and sludge-ceramsite plays an important role in nitrogen transformations. These results suggest that a combination of intermittent aeration and sludge-ceramsite substrate is reliable to enhance the treatment performance in SSF CWs.

  13. Removal of organic pollutants from oak leachate in pilot scale wetland systems: How efficient are aeration and vegetation treatments?

    PubMed

    Svensson, Henric; Ekstam, Börje; Marques, Marcia; Hogland, William

    2015-11-01

    This study investigated the effects of aeration and/or vegetation in experimental constructed wetlands (CWs) as mesocosms on the removal of pollutants in oak wood leachate. Twelve outdoor wetland mesocosms, with randomized replicated treatment combinations of vegetation (Phragmites australis) and aeration was monitored during the second and third year after construction. The investigation included control tanks with no aeration and no vegetation. The parameters monitored were polyphenols (PPs), chemical oxygen demand (COD) and water colour. The reduction of COD after 28 days was approx. 50% and more than 50% of PPs, whereas only 40% of the water colour was removed. Aeration increased the effect of both COD and PP removal. The vegetation treatment had a small but significant effect on removal of COD. The vegetation + aeration treatment, as well as aeration alone, increased the removal efficiency of COD from 9.5 g m(-3) d(-1) in the control to 11 g m(-3) d(-1). The results suggest that CWs can be used to treat stormwater contaminated by oak wood leachate. Further, it is suggested that the main processes for removal of pollutants in the leachate occur in the open-water habitat and that the hydraulic retention time is more important for removal than aeration and vegetation related processes. PMID:26218465

  14. Oxygen demand for the stabilization of the organic fraction of municipal solid waste in passively aerated bioreactors.

    PubMed

    Kasinski, Slawomir; Wojnowska-Baryla, Irena

    2014-02-01

    Conventional aerobic waste treatment technologies require the use of aeration devices that actively transport air through the stabilized waste mass, which greatly increases operating costs. In addition, improperly operated active aeration systems, may have the adverse effect of cooling the stabilized biomass. Because active aeration can be a limiting factor for the stabilization process, passive aeration can be equally effective and less expensive. Unfortunately, there are few reports documenting the use of passive aeration systems in municipal waste stabilization. There have been doubts raised as to whether a passive aeration system provides enough oxygen to the organic matter mineralization processes. In this paper, the effectiveness of aeration during aerobic stabilization of four different organic fractions of municipal waste in a reactor with an integrated passive ventilation system and leachate recirculation was analyzed. For the study, four fractions separated by a rotary screen were chosen. Despite the high temperatures in the reactor, the air flow rate was below 0.016 m(3)/h. Using Darcy's equation, theoretical values of the air flow rate were estimated, depending on the intensity of microbial metabolism and the amount of oxygen required for the oxidation of organic compounds. Calculations showed that the volume of supplied air exceeded the microorganisms demand for oxidation and endogenous activity by 1.7-2.88-fold. PMID:24268917

  15. Removal of organic pollutants from oak leachate in pilot scale wetland systems: How efficient are aeration and vegetation treatments?

    PubMed

    Svensson, Henric; Ekstam, Börje; Marques, Marcia; Hogland, William

    2015-11-01

    This study investigated the effects of aeration and/or vegetation in experimental constructed wetlands (CWs) as mesocosms on the removal of pollutants in oak wood leachate. Twelve outdoor wetland mesocosms, with randomized replicated treatment combinations of vegetation (Phragmites australis) and aeration was monitored during the second and third year after construction. The investigation included control tanks with no aeration and no vegetation. The parameters monitored were polyphenols (PPs), chemical oxygen demand (COD) and water colour. The reduction of COD after 28 days was approx. 50% and more than 50% of PPs, whereas only 40% of the water colour was removed. Aeration increased the effect of both COD and PP removal. The vegetation treatment had a small but significant effect on removal of COD. The vegetation + aeration treatment, as well as aeration alone, increased the removal efficiency of COD from 9.5 g m(-3) d(-1) in the control to 11 g m(-3) d(-1). The results suggest that CWs can be used to treat stormwater contaminated by oak wood leachate. Further, it is suggested that the main processes for removal of pollutants in the leachate occur in the open-water habitat and that the hydraulic retention time is more important for removal than aeration and vegetation related processes.

  16. Influence of aeration modes on leachate characteristic of landfills that adopt the aerobic-anaerobic landfill method.

    PubMed

    Wu, Chuanfu; Shimaoka, Takayuki; Nakayama, Hirofumi; Komiya, Teppei; Chai, Xiaoli; Hao, Yongxia

    2014-01-01

    As far as the optimal design, operation, and field application of the Aerobic-Anaerobic Landfill Method (AALM) are concerned, it is very important to understand how aeration modes (different combinations of aeration depth and air injection rate) affect the biodegradation of organic carbon and the transformation of nitrogen in landfill solid waste. Pilot-scale lysimeter experiments were carried out under different aeration modes to obtain detailed information regarding the influence of aeration modes on leachate characteristics. Results from these lysimeter experiments revealed that aeration at the bottom layer was the most effective for decomposition of organic carbon when compared with aeration at the surface or middle layers. Moreover, the air injection rate led to different nitrogen transformation patterns, unlike the lesser influence it has on organic carbon decomposition. Effective simultaneous nitrification and denitrification were observed for the aeration mode with a higher air injection rate (=1.0 L/min). On the other hand, the phenomenon of sequenced nitrification and denitrification could be observed when a low air injection rate (=0.5L/min.) was employed. Finally, it is concluded that, for AALM, air injection with a higher air injection rate at the deepest layer near the leachate collection pipe tends to accelerate the stabilization of landfill waste as defined in terms of the enhancement of denitrification as well as organic carbon decomposition.

  17. Feasibility study of a passive aeration reactor equipped with vertical pipes for compost stabilization of cow manure.

    PubMed

    Sylla, Youssouf Boundou; Kuroda, Masao; Yamada, Masayuki; Matsumoto, Naoko

    2006-10-01

    Pilot-scale composting was carried out with cow manure to evaluate the performances of two passive aeration systems: a conventional passive aeration system equipped with horizontal pipes and an unusual passive aeration method based on air delivery by means of vertical pipes. The effects of both types of passive aeration apparatus were investigated in order to determine the degree of composting rate by continuously monitoring temperature, moisture content, organic matter, electrical conductivity, pH and C/N ratio in the piles. Temperatures in the range of thermophily (55-65 degrees C) were reached in all runs within 1-2 days then lasting for about 1 week, a span long enough for pathogen abatement. Results suggest that passive aeration carried out by vertical pipes is more effective for air delivery into compost piles than conventional passive aeration of air adduction with horizontal pipes. The variation in the number of vertical pipes was revealed to be an important parameter for the control of composting rate and temperature. Composting rates estimated from the heat balance equation were substantially in agreement with those computed through the conversion ratio of total organic matter decrement. The conversion ratios and composting rates obtained in this study using passive aeration with vertical pipes were well aligned with those found using forced air delivery systems.

  18. Feasibility study of a passive aeration reactor equipped with vertical pipes for compost stabilization of cow manure.

    PubMed

    Sylla, Youssouf Boundou; Kuroda, Masao; Yamada, Masayuki; Matsumoto, Naoko

    2006-10-01

    Pilot-scale composting was carried out with cow manure to evaluate the performances of two passive aeration systems: a conventional passive aeration system equipped with horizontal pipes and an unusual passive aeration method based on air delivery by means of vertical pipes. The effects of both types of passive aeration apparatus were investigated in order to determine the degree of composting rate by continuously monitoring temperature, moisture content, organic matter, electrical conductivity, pH and C/N ratio in the piles. Temperatures in the range of thermophily (55-65 degrees C) were reached in all runs within 1-2 days then lasting for about 1 week, a span long enough for pathogen abatement. Results suggest that passive aeration carried out by vertical pipes is more effective for air delivery into compost piles than conventional passive aeration of air adduction with horizontal pipes. The variation in the number of vertical pipes was revealed to be an important parameter for the control of composting rate and temperature. Composting rates estimated from the heat balance equation were substantially in agreement with those computed through the conversion ratio of total organic matter decrement. The conversion ratios and composting rates obtained in this study using passive aeration with vertical pipes were well aligned with those found using forced air delivery systems. PMID:17121117

  19. Oxygen demand for the stabilization of the organic fraction of municipal solid waste in passively aerated bioreactors

    SciTech Connect

    Kasinski, Slawomir Wojnowska-Baryla, Irena

    2014-02-15

    Highlights: • The use of an passively aerated reactor enables effective stabilization of OFMSW. • Convective air flow does not inhibit the aerobic stabilization of waste. • The use of an passively aerated reactor reduces the heat loss due to convection. • The volume of supplied air exceeds 1.7–2.88 times the microorganisms demand. - Abstract: Conventional aerobic waste treatment technologies require the use of aeration devices that actively transport air through the stabilized waste mass, which greatly increases operating costs. In addition, improperly operated active aeration systems, may have the adverse effect of cooling the stabilized biomass. Because active aeration can be a limiting factor for the stabilization process, passive aeration can be equally effective and less expensive. Unfortunately, there are few reports documenting the use of passive aeration systems in municipal waste stabilization. There have been doubts raised as to whether a passive aeration system provides enough oxygen to the organic matter mineralization processes. In this paper, the effectiveness of aeration during aerobic stabilization of four different organic fractions of municipal waste in a reactor with an integrated passive ventilation system and leachate recirculation was analyzed. For the study, four fractions separated by a rotary screen were chosen. Despite the high temperatures in the reactor, the air flow rate was below 0.016 m{sup 3}/h. Using Darcy’s equation, theoretical values of the air flow rate were estimated, depending on the intensity of microbial metabolism and the amount of oxygen required for the oxidation of organic compounds. Calculations showed that the volume of supplied air exceeded the microorganisms demand for oxidation and endogenous activity by 1.7–2.88-fold.

  20. Optimization of nitrogen removal for alternating intermittent aeration-type activated sludge system: a new process modification.

    PubMed

    Insel, Guclu; Sözen, Seval; Başak, Serden; Orhon, Derin

    2006-01-01

    A new activated sludge process modification was proposed for intermittent aeration process to achieve more stable nitrogen removal performance. A single completely mixed reactor was divided into two compartments in series and operated in intermittent aeration mode by using activated sludge simulation model. The new configuration provided competetive advantage on nitrification as well as denitrification capacity, compared to the intermittently aerated system with a single reactor. In addition, the dissolved oxygen set-point control during air-on periods was found to be an important parameter in terms of nitrogen removal.

  1. Effects of descending positive end-expiratory pressure on lung mechanics and aeration in healthy anaesthetized piglets

    PubMed Central

    Carvalho, Alysson Roncally S; Jandre, Frederico C; Pino, Alexandre V; Bozza, Fernando A; Salluh, Jorge I; Rodrigues, Rosana S; Soares, João HN; Giannella-Neto, Antonio

    2006-01-01

    Introduction Atelectasis and distal airway closure are common clinical entities of general anaesthesia. These two phenomena are expected to reduce the ventilation of dependent lung regions and represent major causes of arterial oxygenation impairment in anaesthetic conditions. The behaviour of the elastance of the respiratory system (Ers), as well as the lung aeration assessed by computed tomography (CT) scan, was evaluated during a descendent positive end-expiratory pressure (PEEP) titration. This work sought to evaluate the potential usefulness of Ers monitoring to set the PEEP in order to prevent tidal recruitment and hyperinflation of healthy lungs under general anaesthesia. Methods PEEP titration (from 16 to 0 cmH2O, tidal volume of 8 ml/kg) was performed, and at each PEEP, CT scans were obtained during end-expiratory and end-inspiratory pauses in six healthy, anaesthetized and paralyzed piglets. The distribution of lung aeration was determined and the tidal re-aeration was calculated as the difference between end-expiratory and end-inspiratory poorly aerated and normally aerated areas. Similarly, tidal hyperinflation was obtained as the difference between end-inspiratory and end-expiratory hyperinflated areas. Ers was estimated from the equation of motion of the respiratory system during all PEEP titration with the least-squares method. Results Hyperinflated areas decreased from PEEP 16 to 0 cmH2O (ranges decreased from 24–62% to 1–7% at end-expiratory pauses and from 44–73% to 4–17% at end-inspiratory pauses) whereas normally aerated areas increased (from 30–66% to 72–83% at end-expiratory pauses and from 19–48% to 73–77% at end-inspiratory pauses). From 16 to 8 cmH2O, Ers decreased with a corresponding reduction in tidal hyperinflation. A flat minimum of Ers was observed from 8 to 4 cmH2O. For PEEP below 4 cmH2O, Ers increased in association with a rise in tidal re-aeration and a flat maximum of the normally aerated areas. Conclusion In

  2. Steam injection system for lunar concrete

    NASA Astrophysics Data System (ADS)

    Pakulski, Dennis M.; Knox, Kenneth J.

    Results of lunar concrete research into steam hydration of concrete currently under way at the USAF Academy by the Department of Civil Engineering are presented. The use of Design of Experiments methodologies to quantify the effects input factors to a process have on the measured responses of the process is demonstrated. The feasibility of hydrating high alumina cement concrete (mortar) using steam injection is shown; the process yields compressible strengths comparable to Portland cement concrete cast with water. The concrete strength is increased with increasing steam exposure (to a point) and with increased density of the dry cement aggregate mixture. Cure time seems to have little effect on the concrete strength.

  3. Optimized aeration strategies for nitrogen and phosphorus removal with aerobic granular sludge.

    PubMed

    Lochmatter, Samuel; Gonzalez-Gil, Graciela; Holliger, Christof

    2013-10-15

    Biological wastewater treatment by aerobic granular sludge biofilms offers the possibility to combine carbon (COD), nitrogen (N) and phosphorus (P) removal in a single reactor. Since denitrification can be affected by suboptimal dissolved oxygen concentrations (DO) and limited availability of COD, different aeration strategies and COD loads were tested to improve N- and P-removal in granular sludge systems. Aeration strategies promoting alternating nitrification and denitrification (AND) were studied to improve reactor efficiencies in comparison with more classical simultaneous nitrification-denitrification (SND) strategies. With nutrient loading rates of 1.6 gCOD L(-1) d(-1), 0.2 gN L(-1) d(-1), and 0.08 gP L(-1) d(-1), and SND aeration strategies, N-removal was limited to 62.3 ± 3.4%. Higher COD loads markedly improved N-removal showing that denitrification was limited by COD. AND strategies were more efficient than SND strategies. Alternating high and low DO phases during the aeration phase increased N-removal to 71.2 ± 5.6% with a COD loading rate of 1.6 gCOD L(-1) d(-1). Periods of low DO were presumably favorable to denitrifying P-removal saving COD necessary for heterotrophic N-removal. Intermittent aeration with anoxic periods without mixing between the aeration pulses was even more favorable to N-removal, resulting in 78.3 ± 2.9% N-removal with the lowest COD loading rate tested. P-removal was under all tested conditions between 88 and 98%, and was negatively correlated with the concentration of nitrite and nitrate in the effluent (r = -0.74, p < 0.01). With low COD loading rates, important emissions of undesired N2O gas were observed and a total of 7-9% of N left the reactor as N2O. However, N2O emissions significantly decreased with higher COD loads under AND conditions.

  4. Ammonia-based intermittent aeration control optimized for efficient nitrogen removal.

    PubMed

    Regmi, Pusker; Bunce, Ryder; Miller, Mark W; Park, Hongkeun; Chandran, Kartik; Wett, Bernhard; Murthy, Sudhir; Bott, Charles B

    2015-10-01

    This work describes the development of an intermittently aerated pilot-scale process (V = 0.45 m(3) ) operated for optimized efficient nitrogen removal in terms of volume, supplemental carbon and alkalinity requirements. The intermittent aeration pattern was controlled using a strategy based on effluent ammonia concentration set-points. The unique feature of the ammonia-based aeration control was that a fixed dissolved oxygen (DO) set-point was used and the length of the aerobic and anoxic time (anoxic time ≥25% of total cycle time) were changed based on the effluent ammonia concentration. Unlike continuously aerated ammonia-based aeration control strategies, this approach offered control over the aerobic solids retention time (SRT) to deal with fluctuating ammonia loading without solely relying on changes to the total SRT. This approach allowed the system to be operated at a total SRT with a small safety factor. The benefits of operating at an aggressive SRT were reduced hydraulic retention time (HRT) for nitrogen removal. As a result of such an operation, nitrite oxidizing bacteria (NOB) out-selection was also obtained (ammonia oxidizing bacteria [AOB] maximum activity: 400 ± 79 mgN/L/d, NOB maximum activity: 257 ± 133 mgN/L/d, P < 0.001) expanding opportunities for short-cut nitrogen removal. The pilot demonstrated a total inorganic nitrogen (TIN) removal rate of 95 ± 30 mgN/L/d at an influent chemical oxygen demand: ammonia (COD/NH4 (+) -N) ratio of 10.2 ± 2.2 at 25°C within the hydraulic retention time (HRT) of 4 h and within a total SRT of 5-10 days. The TIN removal efficiency up to 91% was observed during the study, while effluent TIN was 9.6 ± 4.4 mgN/L. Therefore, this pilot-scale study demonstrates that application of the proposed on-line aeration control is capable of relatively high nitrogen removal without supplemental carbon and alkalinity addition at a low HRT.

  5. Comparison of aeration and spinosad for suppressing insects in stored wheat.

    PubMed

    Flinn, P W; Subramanyam, Bh; Arthur, F H

    2004-08-01

    Field studies were conducted from July 2002 to January 2003 for evaluating the effects of controlled aeration and a commercial biological insecticide, spinosad, in suppressing insect populations in stored wheat. Six cylindrical steel bins were filled with newly harvested (2002 crop year) hard red winter wheat on 9 and 10 July 2002. Each bin contained 30.7 metric tons (1,100 bu) of wheat. Wheat in two bins was left untreated (control), whereas wheat in two bins was treated with spinosad, and in another two bins was subjected to aeration by using aeration controllers. Spinosad was applied to wheat at the time of bin filling to obtain a rate of 1 mg ([AI])/kg. Aeration controllers were set to run the fans when ambient air temperature fell below 23.9, 18.3, and 7.2 degrees C for the first, second, and third cooling cycles, respectively. We added 400 adults each of the rusty grain beetle, Cryptolestes ferrugineus (Stephens); lesser grain borer, Rhyzopertha dominica (F.); and red flour beetle, Tribolium castaneum (Herbst), to the grain at monthly intervals between July and October 2002. Insect density in the bins was estimated monthly by taking 3-kg grain samples from 21 locations within each bin by using a pneumatic grain sampler. No live T. castaneum or C. ferrugineus and very low densities of R. dominica (<0.008 adults per kilogram) were found in wheat treated with spinosad during the 6-mo sampling period. Density of C. ferrugineus and T. castaneum in aerated bins did not exceed two adults per kilogram (the Federal Grain Inspection Service standard for infested wheat), whereas R. dominica increased to 12 adults per kilogram in November 2002, which subsequently decreased to three adults per kilogram in January 2003. In the untreated (control) bins, R. dominica density increased faster than that of C. ferrugineus or T. castaneum. Density of R. dominica peaked at 58 adults per kilogram in October 2002 and decreased subsequently, whereas T. castaneum density was 10 adults

  6. Nanogranular origin of concrete creep.

    PubMed

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-06-30

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium-silicate-hydrates (C-S-H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C-S-H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C-S-H forms: low density, high density, ultra-high density. We demonstrate that the creep rate ( approximately 1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years.

  7. Nanogranular origin of concrete creep

    PubMed Central

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-01-01

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium–silicate–hydrates (C–S–H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C–S–H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C–S–H forms: low density, high density, ultra-high density. We demonstrate that the creep rate (≈1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years. PMID:19541652

  8. 27. DIVERSION STRUCTURE WITH CONCRETE SIDEWALLS AND CONCRETE CHANNEL BEYOND, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. DIVERSION STRUCTURE WITH CONCRETE SIDEWALLS AND CONCRETE CHANNEL BEYOND, A SHORT DISTANCE WEST OF D STREET ABOUT ONE-QUARTER MILE SOUTH OF 9TH AVENUE (SECTION 26). - Highline Canal, Sand Creek Lateral, Beginning at intersection of Peoria Street & Highline Canal in Arapahoe County (City of Aurora), Sand Creek lateral Extends 15 miles Northerly through Araphoe County, City & County of Denver, & Adams County to its end point, approximately 1/4 mile Southest of intersectioin of D Street & Ninth Avenue in Adams County (Rocky Mountain Arsenal, Commerce City Vicinity), Commerce City, Adams County, CO

  9. Effects of aeration rate on degradation process of oil palm empty fruit bunch with kinetic-dynamic modeling.

    PubMed

    Talib, Ahmad Tarmezee; Mokhtar, Mohd Noriznan; Baharuddin, Azhari Samsu; Sulaiman, Alawi

    2014-10-01

    The effect of different aeration rates on the organic matter (OM) degradation during the active phase of oil palm empty fruit bunch (EFB)-rabbit manure co-composting process under constant forced-aeration system has been studied. Four different aeration rates, 0.13 L min(-1) kg(DM)(-1),0.26 L min(-1) kg(DM)(-1),0.49 L min(-1) kg(DM)(-1) and 0.74 L min(-1) kg(DM)(-1) were applied. 0.26 L min(-1) kg(DM)(-1) provided enough oxygen level (10%) for the rest of composting period, showing 40.5% of OM reduction that is better than other aeration rates. A dynamic mathematical model describing OM degradation, based on the ratio between OM content and initial OM content with correction functions of moisture content, free air space, oxygen and temperature has been proposed.

  10. Effects of soil aeration, legume residue, and soil texture on transformations of macro- and micronutrients in soils. [Vicia villosa

    SciTech Connect

    Walters, D.T.; Doran, J.W. ); Aulakh, M.S. )

    1992-02-01

    Soil aeration is an important factor controlling microbial activity, nutrient availability, and plant root growth. The authors investigated the effect of hairy vetch (Vicia villosa) addition to well aerated (60% water-filled pore space (WFPS)) and poorly aerated (90% WFPS) soils of varying texture on transformations of C, N, P, K, Ca, Mg, S, Zn, Mn, Fe, and Cu for a 30-d period. The results of this study imply that incorporation of easily decomposable residue may supply substantial amounts of nutrients to growing plants. Where soils remain wet for > 10 d, residues may create intensive reducing conditions and a several fold increase in available Fe, Mn, Cu, and P. Conversely, DTPA extractable Fe, Mn, and Cu can vary greatly within a few weeks depending on soil aeration status, residue management, time of sampling, and soil texture and may lead to erroneous indices of nutrient availability to plants.

  11. Effects of aeration rate on degradation process of oil palm empty fruit bunch with kinetic-dynamic modeling.

    PubMed

    Talib, Ahmad Tarmezee; Mokhtar, Mohd Noriznan; Baharuddin, Azhari Samsu; Sulaiman, Alawi

    2014-10-01

    The effect of different aeration rates on the organic matter (OM) degradation during the active phase of oil palm empty fruit bunch (EFB)-rabbit manure co-composting process under constant forced-aeration system has been studied. Four different aeration rates, 0.13 L min(-1) kg(DM)(-1),0.26 L min(-1) kg(DM)(-1),0.49 L min(-1) kg(DM)(-1) and 0.74 L min(-1) kg(DM)(-1) were applied. 0.26 L min(-1) kg(DM)(-1) provided enough oxygen level (10%) for the rest of composting period, showing 40.5% of OM reduction that is better than other aeration rates. A dynamic mathematical model describing OM degradation, based on the ratio between OM content and initial OM content with correction functions of moisture content, free air space, oxygen and temperature has been proposed. PMID:25079208

  12. Design of passively aerated compost piles: Vertical air velocities between the pipes

    SciTech Connect

    Lynch, N.J.; Cherry, R.S.

    1996-09-01

    Passively aerated compost piles are built on a base of porous materials, such as straw or wood chips, in which perforated air supply pipes are distributed. The piles are not turned during composting, nor is forced-aeration equipment used, which significantly reduces the operating and capital expenses associated with these piles. Currently, pile configurations and materials are worked out by trial and error. Fundamentally based design procedures are difficult to develop because the natural convection air flow rate is not explicitly known, but rather is closely coupled with the pile temperature. This paper develops a mathematical model to analytically determine the maximum upward air flow velocity over an air supply pipe and the drop in vertical velocity away from the pipe. This model has one dimensionless number, dependent on the pile and base properties, which fully characterizes the velocity profile between the pipes. 9 refs., 4 figs., 1 tab.

  13. Relationship between respiratory quotient, nitrification, and nitrous oxide emissions in a forced aerated composting process.

    PubMed

    Tsutsui, Hirofumi; Fujiwara, Taku; Inoue, Daisuke; Ito, Ryusei; Matsukawa, Kazutsugu; Funamizu, Naoyuki

    2015-08-01

    We assessed the relationship between respiratory quotient (RQ) and nitrification and nitrous oxide (N2O) emission in forced aerated composting using lab-scale reactors. Relatively high RQ values from degradation of readily degradable organics initially occurred. RQ then stabilized at slightly lower values, then decreased. Continuous emission of N2O was observed during the RQ decrease. Correlation between nitrification and N2O emission shows that the latter was triggered by nitrification. Mass balances demonstrated that the O2 consumption of nitrification (∼24.8mmol) was slightly higher than that of CO2 emission (∼20.0mmol), indicating that the RQ decrease was caused by the occurrence of nitrification. Results indicate that RQ is a useful index, which not only reflects the bioavailability of organics but also predicts the occurrence of nitrification and N2O emission in forced aerated composting. PMID:25987285

  14. Enhanced solid waste stabilization in aerobic landfills using low aeration rates and high density compaction.

    PubMed

    El Fadel, Mutasem; Fayad, Wissam; Hashisho, Jihan

    2013-01-01

    Historically, municipal solid waste landfills have been designed and operated as storage facilities with suboptimal degradation under anaerobic conditions resulting in slow waste stabilization, gaseous emissions and leachate formation. This article examines the aerobic bioreactor alternative combining the recirculation of high strength leachate [chemical oxygen demand (COD): 89,000-95,600 mg/l; biological oxygen demand (BOD): 75,700-80,000 mg/l)] with low aeration rates (0.0125-0.05 l/min.kg) at high initial waste compaction (657-875 kg/m3) to promote and control biodegradation of solid waste in laboratory-scale columns (diameter = 60 cm, height = 1 m). Low aeration rates coupled with high initial density demonstrated improved performance with increased levels of stabilization with COD and BOD attenuation reaching up to 96%, final C:N ratio of 25 and waste settlement up to 55%. PMID:22878935

  15. Optimization of Energy Consumption and Mass Transfer Parameters in a Surface Aeration Vessel.

    PubMed

    Mohammadpour, A; AkhavanBehabadi, M A; Ebrahimzadeh, M; Raisee, M; MajdiNasab, A R; Nosrati, M; Mousavi, S M

    2016-04-01

    This paper reports tests on a lab-scale surface aeration vessel was equipped with a Rushton turbine to examine its performance in terms of standard aeration efficiency (SAE), mixing time, and void fraction characteristics. These characteristics were investigated by tests using variations of rotor speed, impeller immersion depth, and water level. Results showed that variation of impeller immersion depth had a greater effect on the SAE compared to variation of water level. Moreover, the SAE increased with rotor speeds up to about 150 to 200 rpm and then decreased. In addition, void fraction improved by impeller immersion depth and rotor speed enhancement; however, mixing time and power number were reduced as rotor speed increased. According to the response surface methodology statistical optimizations, optimum values for rotor speed, impeller immersion depth, and water level were 168.90 rpm, 25 mm, and 30 cm, respectively, to achieve the maximum value of SAE.

  16. Treatment of dilute waste oil emulsion from aluminum rolling mill operations by a biological aerated filter

    SciTech Connect

    Carriere, P.E.; Reed, B.E.; Brooks, J.

    1995-12-31

    Wastewater from aluminum industry contains oil used primarily during the aluminum rolling process. In this study, oily wastewater from the manufacturer`s processes was transferred to two holding ponds having a total capacity of about 5 million gallons. A detention time of 10 days was maintained to allow the free oil to rise to the surface and the solids to settle. Wastewater from the ponds was withdrawn at a depth of 9 feet and used as influent to the pilot-scale biological aerated filter. The main objective of this study was to evaluate the performance of the pilot-scale biological aerated filter on oil and grease (O and G) and total suspended solids (TSS) removal.

  17. Optimization of Energy Consumption and Mass Transfer Parameters in a Surface Aeration Vessel.

    PubMed

    Mohammadpour, A; AkhavanBehabadi, M A; Ebrahimzadeh, M; Raisee, M; MajdiNasab, A R; Nosrati, M; Mousavi, S M

    2016-04-01

    This paper reports tests on a lab-scale surface aeration vessel was equipped with a Rushton turbine to examine its performance in terms of standard aeration efficiency (SAE), mixing time, and void fraction characteristics. These characteristics were investigated by tests using variations of rotor speed, impeller immersion depth, and water level. Results showed that variation of impeller immersion depth had a greater effect on the SAE compared to variation of water level. Moreover, the SAE increased with rotor speeds up to about 150 to 200 rpm and then decreased. In addition, void fraction improved by impeller immersion depth and rotor speed enhancement; however, mixing time and power number were reduced as rotor speed increased. According to the response surface methodology statistical optimizations, optimum values for rotor speed, impeller immersion depth, and water level were 168.90 rpm, 25 mm, and 30 cm, respectively, to achieve the maximum value of SAE. PMID:27131059

  18. Optimization of micro-aeration intensity in acidogenic reactor of a two-phase anaerobic digester treating food waste.

    PubMed

    Xu, Suyun; Selvam, Ammaiyappan; Wong, Jonathan W C

    2014-02-01

    Micro-aeration is known to promote the activities of hydrolytic exo-enzymes and used as a strategy to improve the hydrolysis of particulate substrate. The effect of different micro-aeration rates, 0, 129, 258, and 387 L-air/kg TS/d (denoted as LBR-AN, LBR-6h, LBR-3h and LBR-2h, respectively) on the solubilization of food waste was evaluated at 35°C in four leach bed reactors (LBR) coupled with methanogenic upflow anaerobic sludge blanket (UASB) reactor. Results indicate that the intensity of micro-aeration influenced the hydrolysis and methane yield. Adequate micro-aeration intensity in LBR-3h and LBR-2h significantly enhanced the carbohydrate and protein hydrolysis by 21-27% and 38-64% respectively. Due to the accelerated acidogenesis, more than 3-fold of acetic acid and butyric acid were produced in LBR-3h as compared to the anaerobic treatment LBR-AN resulting in the maximum methane yield of 0.27 L CH4/g VS(added) in the UASB. The performance of LBR-6h with inadequate aeration was similar to that of LBR-AN with a comparable hydrolysis degree. Nevertheless, higher aeration intensity in LBR-2h was also unfavorable for methane yield due to significant biomass generation and CO2 respiration of up to 18.5% and 32.8% of the total soluble hydrolysate, respectively. To conclude, appropriate micro-aeration rate can promote the hydrolysis of solid organic waste and methane yield without undesirable carbon loss and an aeration intensity of 258 L-air/kg TS/d is recommended for acidogenic LBR treating food waste.

  19. Turbine Aeration Design Software for Mitigating Adverse Environmental Impacts Resulting From Conventional Hydropower Turbines

    SciTech Connect

    Gulliver, John S.

    2015-03-01

    Conventional hydropower turbine aeration test-bed for computational routines and software tools for improving environmental mitigation technologies for conventional hydropower systems. In achieving this goal, we have partnered with Alstom, a global leader in energy technology development and United States power generation, with additional funding from the Initiative for Renewable Energy and the Environment (IREE) and the College of Science and Engineering (CSE) at the UMN

  20. Field trial of a new aeration system for enhancing biodegradation in a biopile.

    PubMed

    Li, L; Cunningham, C J; Pas, Valerie; Philp, J C; Barry, D A; Anderson, P

    2004-01-01

    The influence of a new aeration system on the biopile performance was investigated. The purpose was to increase biodegradation efficiency by optimising airflow through the pile. During a 1-month field trial, the performance of a new system using two perforated vertical pipes with wind-driven turbines was compared with that of a standard pile configuration with two horizontal perforated pipes. Both piles were composed of a similar mix of diesel-contaminated soils, woodchips, compost and NPK fertiliser. Hydrocarbons were recovered using solvent extraction, and determined both gravimetrically and by gas chromatography. Total heterotrophs, pH and moisture content were also assessed. Air pressure measurements were made to compare the efficiency of suction in the pipes. Results at the end of the experiment showed that there was no significant difference between the two piles in the total amount of hydrocarbon biodegradation. The normalised degradation rate was, however, considerably higher in the new system than in the standard one, suggesting that the vertical venting method may have improved the efficiency of the biological reactions in the pile. The pressure measurements showed a significant improvement in the suction produced by the new aeration system. However, many factors other than the airflow (oxygen supply) may influence and limit the biodegradation rates, including moisture content, age of contaminants and the climatic conditions. Additional experiments and modelling need to be carried out to explore further the new aeration method and to develop criteria and guidelines for engineering design of optimal aeration schemes in order to achieve maximum biodegradation in biopiles. PMID:14761751

  1. Field trial of a new aeration system for enhancing biodegradation in a biopile.

    PubMed

    Li, L; Cunningham, C J; Pas, Valerie; Philp, J C; Barry, D A; Anderson, P

    2004-01-01

    The influence of a new aeration system on the biopile performance was investigated. The purpose was to increase biodegradation efficiency by optimising airflow through the pile. During a 1-month field trial, the performance of a new system using two perforated vertical pipes with wind-driven turbines was compared with that of a standard pile configuration with two horizontal perforated pipes. Both piles were composed of a similar mix of diesel-contaminated soils, woodchips, compost and NPK fertiliser. Hydrocarbons were recovered using solvent extraction, and determined both gravimetrically and by gas chromatography. Total heterotrophs, pH and moisture content were also assessed. Air pressure measurements were made to compare the efficiency of suction in the pipes. Results at the end of the experiment showed that there was no significant difference between the two piles in the total amount of hydrocarbon biodegradation. The normalised degradation rate was, however, considerably higher in the new system than in the standard one, suggesting that the vertical venting method may have improved the efficiency of the biological reactions in the pile. The pressure measurements showed a significant improvement in the suction produced by the new aeration system. However, many factors other than the airflow (oxygen supply) may influence and limit the biodegradation rates, including moisture content, age of contaminants and the climatic conditions. Additional experiments and modelling need to be carried out to explore further the new aeration method and to develop criteria and guidelines for engineering design of optimal aeration schemes in order to achieve maximum biodegradation in biopiles.

  2. Nitrogen Removal over Nitrite by Aeration Control in Aerobic Granular Sludge Sequencing Batch Reactors

    PubMed Central

    Lochmatter, Samuel; Maillard, Julien; Holliger, Christof

    2014-01-01

    This study investigated the potential of aeration control for the achievement of N-removal over nitrite with aerobic granular sludge in sequencing batch reactors. N-removal over nitrite requires less COD, which is particularly interesting if COD is the limiting parameter for nutrient removal. The nutrient removal performances for COD, N and P have been analyzed as well as the concentration of nitrite-oxidizing bacteria in the granular sludge. Aeration phase length control combined with intermittent aeration or alternate high-low DO, has proven to be an efficient way to reduce the nitrite-oxidizing bacteria population and hence achieve N-removal over nitrite. N-removal efficiencies of up to 95% were achieved for an influent wastewater with COD:N:P ratios of 20:2.5:1. The total N-removal rate was 0.18 kgN·m−3·d−1. With N-removal over nitrate the N-removal was only 74%. At 20 °C, the nitrite-oxidizing bacteria concentration decreased by over 95% in 60 days and it was possible to switch from N-removal over nitrite to N-removal over nitrate and back again. At 15 °C, the nitrite-oxidizing bacteria concentration decreased too but less, and nitrite oxidation could not be completely suppressed. However, the combination of aeration phase length control and high-low DO was also at 15 °C successful to maintain the nitrite pathway despite the fact that the maximum growth rate of nitrite-oxidizing bacteria at temperatures below 20 °C is in general higher than the one of ammonium-oxidizing bacteria. PMID:25006970

  3. Mesocosm-scale evaluation of faunal and microbial communities of aerated and unaerated leachfield soil.

    PubMed

    Amador, José A; Potts, David A; Savin, Mary C; Tomlinson, Peter; Görres, Josef H; Nicosia, Erika L

    2006-01-01

    Aeration improves the capacity of leachfields to decontaminate and reduce the nutrient load of wastewater. To gain a better understanding of the effects of aeration, we examined the faunal and microbial communities of septic system leachfield soil (0-4 and 4-13 cm) using replicated (n = 3) mesocosms that were actively aerated (AIR) or unaerated (LEACH). Protozoa were 40 to 140 times more abundant in AIR than in LEACH soil. No nematodes were found in LEACH soil, whereas AIR soil contained 5 to 14 x 10(3) nematodes (all bacteriovores) kg(-1). Active microbial biomass was four to five times higher in AIR than LEACH soil. Proteobacteria and actinomycetes/sulfate-reducing bacteria constituted a higher proportion of the community in AIR soil, whereas anaerobic Gram-negative bacteria/firmicutes were more prominent in LEACH soil. Ratios of prokaryotic to eukaryotic phospholipid fatty acids (PLFAs) were higher in LEACH soil, as were membrane stress index values, whereas the starvation index was higher in AIR soil. Community-level physiological profiles showed that 29 and 30 different substrates were used for growth by LEACH and AIR soil microorganisms, respectively. The AIR soil had more microorganisms capable of growing on 10 substrates, whereas growth on two substrates was higher in LEACH soil. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis of 16S rRNA gene fragments revealed greater diversity of dominant phylotypes in AIR than LEACH soil, with communities separated by treatment. Aerated leachfield soil had a larger and more diverse faunal and microbial community than unaerated soil, possibly due to differences in the type and availability of electron acceptors.

  4. A Trade Study of Two Membrane-Aerated Biological Water Processors

    NASA Technical Reports Server (NTRS)

    Allada, Ram; Lange, Kevin; Vega. Leticia; Roberts, Michael S.; Jackson, Andrew; Anderson, Molly; Pickering, Karen

    2011-01-01

    Biologically based systems are under evaluation as primary water processors for next generation life support systems due to their low power requirements and their inherent regenerative nature. This paper will summarize the results of two recent studies involving membrane aerated biological water processors and present results of a trade study comparing the two systems with regards to waste stream composition, nutrient loading and system design. Results of optimal configurations will be presented.

  5. Effects of the combination of aeration and biofilm technology on transformation of nitrogen in black-odor river.

    PubMed

    Pan, Mei; Zhao, Jun; Zhen, Shucong; Heng, Sheng; Wu, Jie

    2016-01-01

    Excess nitrogen in urban river networks leading to eutrophication has become one of the most urgent environmental problems. Combinations of different aeration and biofilm techniques was designed to remove nitrogen from rivers. In laboratory water tank simulation experiments, we assessed the removal efficiency of nitrogen in both the overlying water and sediments by using the combination of the aeration and biofilm techniques, and then analyzed the transformation of nitrogen during the experiments. Aeration (especially sediment aeration) combined with the biofilms techniques was proved efficient in removing nitrogen from polluted rivers. Results indicated that the combination of sediment aeration and biofilms, with the highest nitrogen removal rate from the overlying water and sediments, was the most effective combined process, which especially inhibited the potential release of nitrogen from sediments by reducing the enzyme activity. It was found that the content of dissolved oxygen in water could be restored on the basis of the application of aeration techniques ahead, and the biofilm technique would be effective in purifying water in black-odor rivers. PMID:27508370

  6. Effects of the combination of aeration and biofilm technology on transformation of nitrogen in black-odor river.

    PubMed

    Pan, Mei; Zhao, Jun; Zhen, Shucong; Heng, Sheng; Wu, Jie

    2016-01-01

    Excess nitrogen in urban river networks leading to eutrophication has become one of the most urgent environmental problems. Combinations of different aeration and biofilm techniques was designed to remove nitrogen from rivers. In laboratory water tank simulation experiments, we assessed the removal efficiency of nitrogen in both the overlying water and sediments by using the combination of the aeration and biofilm techniques, and then analyzed the transformation of nitrogen during the experiments. Aeration (especially sediment aeration) combined with the biofilms techniques was proved efficient in removing nitrogen from polluted rivers. Results indicated that the combination of sediment aeration and biofilms, with the highest nitrogen removal rate from the overlying water and sediments, was the most effective combined process, which especially inhibited the potential release of nitrogen from sediments by reducing the enzyme activity. It was found that the content of dissolved oxygen in water could be restored on the basis of the application of aeration techniques ahead, and the biofilm technique would be effective in purifying water in black-odor rivers.

  7. The effect of aeration and effluent recycling on domestic wastewater treatment in a pilot-plant system of duckweed ponds.

    PubMed

    Ben-shalom, Miriam; Shandalov, Semion; Brenner, Asher; Oron, Gideon

    2014-01-01

    Three pilot-scale duckweed pond (DP) wastewater treatment systems were designed and operated to examine the effect of aeration and effluent recycling on treatment efficiency. Each system consisted of two DPs in series fed by pre-settled domestic sewage. The first system (duckweed+ conventional treatment) was 'natural' and included only duckweed plants. The second system (duckweed aeration) included aeration in the second pond. The third system (duckweed+ aeration+ circulation) included aeration in the second pond and effluent recycling from the second to the first pond. All three systems demonstrated similarly efficient removal of organic matter and nutrients. Supplemental aeration had no effect on either dissolved oxygen levels or on pollutant removal efficiencies. Although recycling had almost no influence on nutrient removal efficiencies, it had a positive impact on chemical oxygen demand and total suspended solids removals due to equalization of load and pH, which suppressed algae growth. Recycling also improved the appearance and growth rate of the duckweed plants, especially during heavy wastewater loads.

  8. Clinical and Molecular Epidemiology of Multidrug-Resistant P. aeruginosa Carrying aac(6')-Ib-cr, qnrS1 and blaSPM Genes in Brazil

    PubMed Central

    Araujo, Bruna Fuga; Ferreira, Melina Lorraine; de Campos, Paola Amaral; Royer, Sabrina; Batistão, Deivid William da Fonseca; Dantas, Raquel Cristina Cavalcanti; Gonçalves, Iara Rossi; Faria, Ana Luiza Souza; de Brito, Cristiane Silveira; Yokosawa, Jonny; Gontijo-Filho, Paulo Pinto; Ribas, Rosineide Marques

    2016-01-01

    We described a comprehensive analysis of the molecular epidemiology of multidrug-resistant (MDR) P. aeruginosa. Molecular analysis included typing by Pulsed Field Gel Electrophoresis, identification of genes of interest through PCR-based assays and sequencing of target genes. Case-control study was conducted to better understand the prognostic of patients and the impact of inappropriate therapy in patients with bacteremia, as well as the risk factors of MDR infections. We observed a high rate of MDR isolates (40.7%), and 51.0% of them was independently associated with inappropriate antibiotic therapy. Bacteremia was detected in 66.9% of patients, and prolonged hospital stay was expressive in those resistant to fluoroquinolone. Plasmid-mediated quinolone resistance genes (PMQR), qnrS1 and aac(6’)Ib-cr, were detected in two different nosocomial isolates (5.3%), and the aac(6’)-Ib7 variant was detected at a high frequency (87.5%) in those negative to PMQR. The presence of mutations in gyrA and parC genes was observed in 100% and 85% of selected isolates, respectively. Isolates harboring PMQR genes or mutations in gyrA and parC were not closely related, except in those containing SPM (São Paulo metallo-β-lactamase) clone. In addition, there is no study published in Brazil to date reporting the presence of Pseudomonas aeruginosa isolates harboring both qnrS1 and aac(6’)Ib-cr genes, with alarming frequency of patients with inappropriate therapy. PMID:27219003

  9. Relationship between respiratory quotient, nitrification, and nitrous oxide emissions in a forced aerated composting process

    SciTech Connect

    Tsutsui, Hirofumi; Fujiwara, Taku; Inoue, Daisuke; Ito, Ryusei; Matsukawa, Kazutsugu; Funamizu, Naoyuki

    2015-08-15

    Highlights: • RQ can be an indicator of N{sub 2}O emission in forced aerated composting process. • Emission of N{sub 2}O with nitrification was observed with RQ decrease. • Mass balances demonstrated the RQ decrease was caused by nitrification. • Conversion ratio of oxidized ammonia and total N to N{sub 2}O were ∼2.7%. - Abstract: We assessed the relationship between respiratory quotient (RQ) and nitrification and nitrous oxide (N{sub 2}O) emission in forced aerated composting using lab-scale reactors. Relatively high RQ values from degradation of readily degradable organics initially occurred. RQ then stabilized at slightly lower values, then decreased. Continuous emission of N{sub 2}O was observed during the RQ decrease. Correlation between nitrification and N{sub 2}O emission shows that the latter was triggered by nitrification. Mass balances demonstrated that the O{sub 2} consumption of nitrification (∼24.8 mmol) was slightly higher than that of CO{sub 2} emission (∼20.0 mmol), indicating that the RQ decrease was caused by the occurrence of nitrification. Results indicate that RQ is a useful index, which not only reflects the bioavailability of organics but also predicts the occurrence of nitrification and N{sub 2}O emission in forced aerated composting.

  10. Computational fluid dynamics simulations of membrane filtration process adapted for water treatment of aerated sewage lagoons.

    PubMed

    Cano, Grégory; Mouahid, Adil; Carretier, Emilie; Guasp, Pascal; Dhaler, Didier; Castelas, Bernard; Moulin, Philippe

    2015-01-01

    The aim of this study is to apply the membrane bioreactor technology in an oxidation ditch in submerged conditions. This new wastewater filtration process will benefit rural areas (<5,000 population equivalent) subject to chronic water shortages by reusing this water for irrigation of green areas. For this purpose, the membranes developed without support are immersed in an aeration well and work in suction mode. The development of the membrane without support and more precisely the performance of spacers are approached by computational fluid dynamics in order to provide the best compromise between pressure drop/flow velocity and permeate flux. The numerical results on the layout and the membrane modules' geometry in the aeration well indicate that the optimal configuration is to install the membranes horizontally on three levels. Membranes should be connected to each other to a manifold providing a total membrane area of 18 m². Loss rate compared to the theoretical throughput is relatively low (less than 3%). Preliminary data obtained by modeling the lagoon provide access to its hydrodynamics, revealing that recirculation zones can be optimized by making changes in the operating conditions. The experimental validation of these results and taking into account the aeration in the numerical models are underway. PMID:25633942

  11. Power generation from cassava alcohol wastewater: effects of pretreatment and anode aeration.

    PubMed

    Quan, Xiangchun; Tao, Kun; Mei, Ying; Jiang, Xiaoman

    2014-11-01

    Cassava alcohol wastewater produced from the bioethanol production industry is carbohydrate-rich wastewater with large quantities of insoluble organic compounds. Microbial fuel cells (MFCs) were used for electricity recovery and pollutants removal from this wastewater. Different pretreatment methods (solid-liquid separation, ultrasonication, pre-fermentation) and anode-aeration modes were explored in MFCs aimed to enhance the efficiency of power generation and pollutants removal. Pre-fermentation was found to be the most effective pretreatment method. A maximum power density of 437.13 ± 15.6 mW/m(2) and TCOD removal of 62.5 ± 3.5% were achieved using the pre-fermented wastewater, 150 and 20% higher than the un-pretreated control. Aeration in anode chamber could promote the hydrolysis of organic matter and production of VFAs in the raw wastewater, and increase TCOD removal and power density. Pre-fermentation coupled with halfway anode aeration may be a feasible strategy to enhance power generation and pollutants removal from the cassava wastewater in MFCs. PMID:24842224

  12. Evaluation of aerated biofilter systems for microbial methane oxidation of poor landfill gas.

    PubMed

    Haubrichs, R; Widmann, R

    2006-01-01

    In the long-term, landfills are producing landfill gas (LFG) with low calorific values. Therefore, the utilization of LFG in combined heat and power plants (CHP) is limited to a certain period of time. A feasible method for LFG treatment is microbial CH(4) oxidation. Different materials were tested in actively aerated lab-scale bio-filter systems with a volume of 0.167 m(3). The required oxygen for the microbial CH(4) oxidation was provided through perforated probes, which distributed ambient air into the filter material. Three air input levels were installed along the height of the filter, each of them adjusted to a particular flow rate. During the tests, stable degradation rates of around 28 g/(m(3) h) in a fine-grained compost material were observed at a CH(4) inlet concentration of 30% over a period of 148 days. Compared with passive (not aerated) tests, the CH(4) oxidation rate increased by a factor of 5.5. Therefore, the enhancement of active aeration on the microbial CH(4) oxidation was confirmed. At a O(2)/CH(4) ratio of 2.5, nearly 100% of the CH(4) load was decomposed. By lowering the ratio from 2.5 to 2, the efficiency fell to values from 88% to 92%. By varying the distribution to the three air input levels, the CH(4) oxidation process was spread more evenly over the filter volume. PMID:16386886

  13. Mechanism and design of intermittent aeration activated sludge process for nitrogen removal.

    PubMed

    Hanhan, Oytun; Insel, Güçlü; Yagci, Nevin Ozgur; Artan, Nazik; Orhon, Derin

    2011-01-01

    The paper provided a comprehensive evaluation of the mechanism and design of intermittent aeration activated sludge process for nitrogen removal. Based on the specific character of the process the total cycle time, (T(C)), the aerated fraction, (AF), and the cycle time ratio, (CTR) were defined as major design parameters, aside from the sludge age of the system. Their impact on system performance was evaluated by means of process simulation. A rational design procedure was developed on the basis of basic stochiometry and mass balance related to the oxidation and removal of nitrogen under aerobic and anoxic conditions, which enabled selected of operation parameters of optimum performance. The simulation results indicated that the total nitrogen level could be reduced to a minimum level by appropriate manipulation of the aerated fraction and cycle time ratio. They also showed that the effluent total nitrogen could be lowered to around 4.0 mgN/L by adjusting the dissolved oxygen set-point to 0.5 mg/L, a level which promotes simultaneous nitrification and denitrification.

  14. Evaluation of aerated biofilter systems for microbial methane oxidation of poor landfill gas.

    PubMed

    Haubrichs, R; Widmann, R

    2006-01-01

    In the long-term, landfills are producing landfill gas (LFG) with low calorific values. Therefore, the utilization of LFG in combined heat and power plants (CHP) is limited to a certain period of time. A feasible method for LFG treatment is microbial CH(4) oxidation. Different materials were tested in actively aerated lab-scale bio-filter systems with a volume of 0.167 m(3). The required oxygen for the microbial CH(4) oxidation was provided through perforated probes, which distributed ambient air into the filter material. Three air input levels were installed along the height of the filter, each of them adjusted to a particular flow rate. During the tests, stable degradation rates of around 28 g/(m(3) h) in a fine-grained compost material were observed at a CH(4) inlet concentration of 30% over a period of 148 days. Compared with passive (not aerated) tests, the CH(4) oxidation rate increased by a factor of 5.5. Therefore, the enhancement of active aeration on the microbial CH(4) oxidation was confirmed. At a O(2)/CH(4) ratio of 2.5, nearly 100% of the CH(4) load was decomposed. By lowering the ratio from 2.5 to 2, the efficiency fell to values from 88% to 92%. By varying the distribution to the three air input levels, the CH(4) oxidation process was spread more evenly over the filter volume.

  15. Computational Fluid Dynamics Simulation of Flows in an Oxidation Ditch Driven by a New Surface Aerator

    PubMed Central

    Huang, Weidong; Li, Kun; Wang, Gan; Wang, Yingzhe

    2013-01-01

    Abstract In this article, we present a newly designed inverse umbrella surface aerator, and tested its performance in driving flow of an oxidation ditch. Results show that it has a better performance in driving the oxidation ditch than the original one with higher average velocity and more uniform flow field. We also present a computational fluid dynamics model for predicting the flow field in an oxidation ditch driven by a surface aerator. The improved momentum source term approach to simulate the flow field of the oxidation ditch driven by an inverse umbrella surface aerator was developed and validated through experiments. Four kinds of turbulent models were investigated with the approach, including the standard k−ɛ model, RNG k−ɛ model, realizable k−ɛ model, and Reynolds stress model, and the predicted data were compared with those calculated with the multiple rotating reference frame approach (MRF) and sliding mesh approach (SM). Results of the momentum source term approach are in good agreement with the experimental data, and its prediction accuracy is better than MRF, close to SM. It is also found that the momentum source term approach has lower computational expenses, is simpler to preprocess, and is easier to use. PMID:24302850

  16. [Treatment of petrochemical secondary effluent by ozone-biological aerated filter].

    PubMed

    Liu, Ming-Guo; Wu, Chang-Yong; Zhou, Yue-Xi; Gao, Zhen; Wang, Pei-Chao; Yang, Qi; Dong, De

    2014-02-01

    The advanced treatment of petrochemical secondary wastewater by ozone- aerated biological filter was carried out in this study. The effect of pH on ozonation and the removal of COD and UV254 by the ozone-aerated biological filter combined process were investigated. In addition, the variation of relative molecular mass distribution of organics and the characteristics of three-dimensional fluorescence spectra of the wastewater were also investigated. The results showed that the suitable operating conditions of the ozonation unit were: ozone dosage 10 mg x L(-1), contact time 4 min and slightly alkaline pH. Ozonation can transfer macromolecular organics into small molecular organics, resulting in a 15% increase in the percentage of the organics with small relative molecular mass (less than 1 000). The biodegradability of the petrochemical secondary effluent was significantly improved by ozonation, making it more suitable for the treatment by aerated biological filter. The removal efficiency of COD and UV254 were 40.8% and 45.8% when the hydraulic retention time was 3 hours and the gas to water ratio was 3:1 for BAF. The average COD of the petrochemical wastewater was 86.5 mg x L(-1) while the average COD of the effluent of the combined process was 49.4 mg x L(-1) when it was operated under optimal conditions.

  17. Treatment of sewage sludge in a thermophilic membrane reactor (TMR) with alternate aeration cycles.

    PubMed

    Collivignarelli, Maria Cristina; Castagnola, Federico; Sordi, Marco; Bertanza, Giorgio

    2015-10-01

    The management of sewage sludge is becoming a more and more important issue, both at national and international level, in particular due to the uncertain recovery/disposal future options. Therefore, it is clear that the development of new technologies that can mitigate the problem at the source by reducing sludge production is necessary, such as the European Directive 2008/98/EC prescribes. This work shows the results obtained with a thermophilic membrane reactor, for processing a biological sludge derived from a wastewater treatment plant (WWTP) that treats urban and industrial wastewater. Sewage sludge was treated in a thermophilic membrane reactor (TMR), at pilot-scale (1 m(3) volume), with alternate aeration cycles. The experimentation was divided into two phases: a "startup phase" during which, starting with a psychrophilic/mesophilic biomass, thermophilic conditions were progressively reached, while feeding a highly biodegradable substrate; the obtained thermophilic biomass was then used, in the "regime phase", to digest biological sludge which was fed to the plant. Good removal yields were observed: 64% and 57% for volatile solids (VS) and total COD (CODtot), respectively, with an average hydraulic retention time (HRT) equal to 20 d, an organic loading rate (OLR) of about 1.4-1.8 kg COD m(-3) d(-1) and aeration/non aeration cycles alternated every 4 h.

  18. Multiple electron transfer systems in oxygen reducing biocathodes revealed by different conditions of aeration/agitation.

    PubMed

    Rimboud, Mickaël; Bergel, Alain; Erable, Benjamin

    2016-08-01

    Oxygen reducing biocathodes were formed at -0.2V/SCE (+0.04V/SHE) from compost leachate. Depending on whether aeration was implemented or not, two different redox systems responsible for the electrocatalysis of oxygen reduction were evidenced. System I was observed at low potential (-0.03V/SHE) on cyclic voltammetries (CVs). It appeared during the early formation of the biocathode (few hours) and resisted the hydrodynamic conditions induced by the aeration. System II was observed at higher potential on CV (+0.46V/SHE); it required a longer lag time (up to 10days) and quiescent conditions to produce an electrochemical signal. The hydrodynamic effects produced by the forced aeration led to its extinction. From their different behaviors and examples in the literature, system I was identified as being a membrane-bound cytochrome-related molecule, while system II was identified as a soluble redox mediator excreted by the biofilm. This study highlighted the importance of controlling the local hydrodynamics to design efficient oxygen reducing biocathodes able to operate at high potential.

  19. Bio-oxidation of airborne volatile organic compounds in an activated sludge aeration tank.

    PubMed

    Chou, Ming-Shean; Chang, Hsiao-Yu

    2005-05-01

    An activated sludge aeration tank (40 x 40 x 300 cm, width x length x height) with a set of 2-mm orifice air spargers was used to treat gas-borne volatile organic compounds (VOCs; toluene, p-xylene, and dichloromethane) in air streams. The effects of liquid depth (Z), aeration intensity (G/A), the overall mass-transfer rate of oxygen in clean water (KLaO2), the Henry's law constant of the tested VOC (H), and the influent gaseous VOC concentration (C0) on the efficiency of removal of VOCs were examined and compared with a literature-cited model. Results show that the measured VOC removal efficiencies and those predicted by the model were comparable at a G/A of 3.75-11.25 m3/m2 hr and C0 of approximately 1000-6000 mg/m3. Experimental data also indicated that the designed gas treatment reactor with KLaO2 = 5-15 hr(-l) could achieve > 85% removal of VOCs with H = 0.24-0.25 at an aerated liquid depth of 1 m and > 95% removal of dichloromethane with H = 0.13 at a 1-m liquid depth.

  20. Computational fluid dynamics simulations of membrane filtration process adapted for water treatment of aerated sewage lagoons.

    PubMed

    Cano, Grégory; Mouahid, Adil; Carretier, Emilie; Guasp, Pascal; Dhaler, Didier; Castelas, Bernard; Moulin, Philippe

    2015-01-01

    The aim of this study is to apply the membrane bioreactor technology in an oxidation ditch in submerged conditions. This new wastewater filtration process will benefit rural areas (<5,000 population equivalent) subject to chronic water shortages by reusing this water for irrigation of green areas. For this purpose, the membranes developed without support are immersed in an aeration well and work in suction mode. The development of the membrane without support and more precisely the performance of spacers are approached by computational fluid dynamics in order to provide the best compromise between pressure drop/flow velocity and permeate flux. The numerical results on the layout and the membrane modules' geometry in the aeration well indicate that the optimal configuration is to install the membranes horizontally on three levels. Membranes should be connected to each other to a manifold providing a total membrane area of 18 m². Loss rate compared to the theoretical throughput is relatively low (less than 3%). Preliminary data obtained by modeling the lagoon provide access to its hydrodynamics, revealing that recirculation zones can be optimized by making changes in the operating conditions. The experimental validation of these results and taking into account the aeration in the numerical models are underway.

  1. Impact of carbon to nitrogen ratio and aeration regime on mainstream deammonification.

    PubMed

    Han, M; De Clippeleir, H; Al-Omari, A; Wett, B; Vlaeminck, S E; Bott, C; Murthy, S

    2016-01-01

    While deammonification of high-strength wastewater in the sludge line of sewage treatment plants has become well established, the potential cost savings spur the development of this technology for mainstream applications. This study aimed at identifying the effect of aeration and organic carbon on the deammonification process. Two 10 L sequencing bath reactors with different aeration frequencies were operated at 25°C. Real wastewater effluents from chemically enhanced primary treatment and high-rate activated sludge process were fed into the reactors with biodegradable chemical oxygen demand/nitrogen (bCOD/N) of 2.0 and 0.6, respectively. It was found that shorter aerobic solids retention time (SRT) and higher aeration frequency gave more advantages for aerobic ammonium-oxidizing bacteria (AerAOB) than nitrite oxidizing bacteria (NOB) in the system. From the kinetics study, it is shown that the affinity for oxygen is higher for NOB than for AerAOB, and higher dissolved oxygen set-point could decrease the affinity of both AerAOB and NOB communities. After 514 days of operation, it was concluded that lower organic carbon levels enhanced the activity of anoxic ammonium-oxidizing bacteria (AnAOB) over denitrifiers. As a result, the contribution of AnAOB to nitrogen removal increased from 40 to 70%. Overall, a reasonably good total removal efficiency of 66% was reached under a low bCOD/N ratio of 2.0 after adaptation. PMID:27438242

  2. Effect of forced aeration on citric acid production by Aspergillus sp. mutants in SSF.

    PubMed

    Rodrigues, Cristine; Vandenberghe, Luciana P S; Sturm, Wilerson; Dergint, Dario E A; Spier, Michele Rigon; de Carvalho, Júlio Cesar; Soccol, Carlos R

    2013-12-01

    Citric acid (CA) is one of the most important products of fermentation in the world. A great variety of agro-industrial residues can be used in solid state fermentation. Aspergillus niger parental strain (CCT 7716) and two strains obtained by mutagenesis (CCT 7717 and CCT 7718) were evaluated in Erlenmeyer flasks and glass columns using citric pulp (CP) as substrate/support, sugarcane molasses and methanol. Best results using glass columns (forced aeration) were found in the fourth day of fermentation: 278.4, 294.9 and 261.1 g CA/kg of dry CP with CCT 7716, CCT 7718 and CCT 7717, respectively. In Erlenmeyer flasks (aeration by diffusion) CA reached 410.7, 446.8 and 492.7 g CA/kg of dry CP with CCT 7716, CCT 7718 and CCT 7717, respectively. The aeration by diffusion improved CA production by the three strains. A data acquisition system specially developed for biotechnological processes analysis was used to perform the respirometric parameters measurement.

  3. Thermophilic aeration of cattle slurry with whey and/or jam wastes.

    PubMed

    Heinonen-Tanski, Helvi; Kiuru, Tapio; Ruuskanen, Juhani; Korhonen, Kari; Koivunen, Jari; Ruokojärvi, Arja

    2005-01-01

    Thermophilic aeration of cattle slurry and food industrial by-products was studied with the aim to improve hygienic qualities of the slurry so that it could be used as a safe fertiliser for berries to be eaten raw. We also wanted to study if the process would be energetically favourable in an arctic climate. Cattle slurry alone or with whey and/or jam waste was treated. The tests were done in a well heat-insulated reactor with a 10 m(3) volume. Temperature increases up to over 70 degrees C could be recorded in 19 days even though some processes were carried out in winter time when the ambient air temperature was less than 0 degrees C. The heat energy formed was higher than the electrical energy needed to carry out the aeration. The hygienic qualities of the aerated product were good with only minor nitrogen losses. The end product could be useful as a fertiliser and soil improving compound to increase the organic matter content of agricultural soil. Cattle slurry alone was well suited as the raw material if attaining a high temperature was the main goal. A part of slurry could be replaced with food-industrial side products. Whey waste suited better for co-composting than jam waste but the mixture of whey, jam waste, and slurry was optimal for composting.

  4. Power generation from cassava alcohol wastewater: effects of pretreatment and anode aeration.

    PubMed

    Quan, Xiangchun; Tao, Kun; Mei, Ying; Jiang, Xiaoman

    2014-11-01

    Cassava alcohol wastewater produced from the bioethanol production industry is carbohydrate-rich wastewater with large quantities of insoluble organic compounds. Microbial fuel cells (MFCs) were used for electricity recovery and pollutants removal from this wastewater. Different pretreatment methods (solid-liquid separation, ultrasonication, pre-fermentation) and anode-aeration modes were explored in MFCs aimed to enhance the efficiency of power generation and pollutants removal. Pre-fermentation was found to be the most effective pretreatment method. A maximum power density of 437.13 ± 15.6 mW/m(2) and TCOD removal of 62.5 ± 3.5% were achieved using the pre-fermented wastewater, 150 and 20% higher than the un-pretreated control. Aeration in anode chamber could promote the hydrolysis of organic matter and production of VFAs in the raw wastewater, and increase TCOD removal and power density. Pre-fermentation coupled with halfway anode aeration may be a feasible strategy to enhance power generation and pollutants removal from the cassava wastewater in MFCs.

  5. Mechanism and design of intermittent aeration activated sludge process for nitrogen removal.

    PubMed

    Hanhan, Oytun; Insel, Güçlü; Yagci, Nevin Ozgur; Artan, Nazik; Orhon, Derin

    2011-01-01

    The paper provided a comprehensive evaluation of the mechanism and design of intermittent aeration activated sludge process for nitrogen removal. Based on the specific character of the process the total cycle time, (T(C)), the aerated fraction, (AF), and the cycle time ratio, (CTR) were defined as major design parameters, aside from the sludge age of the system. Their impact on system performance was evaluated by means of process simulation. A rational design procedure was developed on the basis of basic stochiometry and mass balance related to the oxidation and removal of nitrogen under aerobic and anoxic conditions, which enabled selected of operation parameters of optimum performance. The simulation results indicated that the total nitrogen level could be reduced to a minimum level by appropriate manipulation of the aerated fraction and cycle time ratio. They also showed that the effluent total nitrogen could be lowered to around 4.0 mgN/L by adjusting the dissolved oxygen set-point to 0.5 mg/L, a level which promotes simultaneous nitrification and denitrification. PMID:21104491

  6. Carbonation and its effects in reinforced concrete

    SciTech Connect

    Broomfield, J.P.

    2000-01-01

    Carbonation is the result of interaction of carbon dioxide (CO{sub 2}) gas in the atmosphere with the alkaline hydroxides in the concrete. CO{sub 2} diffuses through the concrete and rate of movement of the carbonation front roughly follows Fick's law of diffusion. Carbonation depth can be measured by exposing fresh concrete and spraying it with phenolphthalein indicator solution. An example of the test on a reinforced concrete mullion is given.

  7. Klebsiella pneumoniae clinical isolate coproducing SHV-2a, DHA-1, QnrB4, and AAC(6')-Ib-cr determinants in France.

    PubMed

    Corvec, Stéphane; Crémet, Lise; Caroff, Nathalie; Dauvergne, Sandie; Le Floch, Ronan; Reynaud, Alain; Lepelletier, Didier; Bémer, Pascale

    2009-08-01

    We report on a Klebsiella pneumoniae clinical isolate coproducing bla(DHA-1), bla(SHV-2a), qnrB4, and aac(6')-Ib-cr genes. Molecular analysis demonstrated the presence of this combination on the same large plasmid. Despite a negative result for extended-spectrum beta-lactamase (ESBL) by Vitek2(R) system (bioMérieux, Marcy-l'Etoile, France), an ESBL was detected by a double-disk test. Phenotypic techniques and molecular analysis are key approaches to determine coresistance.

  8. QnrS1- and Aac(6′)-Ib-cr-Producing Escherichia coli among Isolates from Animals of Different Sources: Susceptibility and Genomic Characterization

    PubMed Central

    Jones-Dias, Daniela; Manageiro, Vera; Graça, Rafael; Sampaio, Daniel A.; Albuquerque, Teresa; Themudo, Patrícia; Vieira, Luís; Ferreira, Eugénia; Clemente, Lurdes; Caniça, Manuela

    2016-01-01

    Salmonella enterica and Escherichia coli can inhabit humans and animals from multiple origins. These bacteria are often associated with gastroenteritis in animals, being a frequent cause of resistant zoonotic infections. In fact, bacteria from animals can be transmitted to humans through the food chain and direct contact. In this study, we aimed to assess the antibiotic susceptibility of a collection of S. enterica and E. coli recovered from animals of different sources, performing a genomic comparison of the plasmid-mediated quinolone resistance (PMQR)-producing isolates detected. Antibiotic susceptibility testing revealed a high number of non-wild-type isolates for fluoroquinolones among S. enterica recovered from poultry isolates. In turn, the frequency of non-wild-type E. coli to nalidixic acid and ciprofloxacin was higher in food-producing animals than in companion or zoo animals. Globally, we detected two qnrS1 and two aac(6′)-Ib-cr in E. coli isolates recovered from animals of different origins. The genomic characterization of QnrS1-producing E. coli showed high genomic similarity (O86:H12 and ST2297), although they have been recovered from a healthy turtle dove from a Zoo Park, and from a dog showing symptoms of infection. The qnrS1 gene was encoded in a IncN plasmid, also carrying blaTEM−1−containing Tn3. Isolates harboring aac(6′)-Ib-cr were detected in two captive bottlenose dolphins, within a time span of two years. The additional antibiotic resistance genes of the two aac(6′)-Ib-cr-positive isolates (blaOXA−1, blaTEM−1,blaCTX−M−15, catB3, aac(3)-IIa, and tetA) were enclosed in IncFIA plasmids that differed in a single transposase and 60 single nucleotide variants. The isolates could be assigned to the same genetic sublineage—ST131 fimH30-Rx (O25:H4), confirming clonal spread. PMQR-producing isolates were associated with symptomatic and asymptomatic hosts, which highlight the aptitude of E. coli to act as silent vehicles, allowing

  9. Using Visual Scene Displays as Communication Support Options for People with Chronic, Severe Aphasia: A Summary of AAC Research and Future Research Directions.

    PubMed

    Beukelman, David R; Hux, Karen; Dietz, Aimee; McKelvey, Miechelle; Weissling, Kristy

    2015-01-01

    Research about the effectiveness of communicative supports and advances in photographic technology has prompted changes in the way speech-language pathologists design and implement interventions for people with aphasia. The purpose of this paper is to describe the use of photographic images as a basis for developing communication supports for people with chronic aphasia secondary to sudden-onset events due to cerebrovascular accidents (strokes). Topics include the evolution of AAC-based supports as they relate to people with aphasia, the development and key features of visual scene displays (VSDs), and future directions concerning the incorporation of photographs into communication supports for people with chronic and severe aphasia.

  10. QnrS1- and Aac(6')-Ib-cr-Producing Escherichia coli among Isolates from Animals of Different Sources: Susceptibility and Genomic Characterization.

    PubMed

    Jones-Dias, Daniela; Manageiro, Vera; Graça, Rafael; Sampaio, Daniel A; Albuquerque, Teresa; Themudo, Patrícia; Vieira, Luís; Ferreira, Eugénia; Clemente, Lurdes; Caniça, Manuela

    2016-01-01

    Salmonella enterica and Escherichia coli can inhabit humans and animals from multiple origins. These bacteria are often associated with gastroenteritis in animals, being a frequent cause of resistant zoonotic infections. In fact, bacteria from animals can be transmitted to humans through the food chain and direct contact. In this study, we aimed to assess the antibiotic susceptibility of a collection of S. enterica and E. coli recovered from animals of different sources, performing a genomic comparison of the plasmid-mediated quinolone resistance (PMQR)-producing isolates detected. Antibiotic susceptibility testing revealed a high number of non-wild-type isolates for fluoroquinolones among S. enterica recovered from poultry isolates. In turn, the frequency of non-wild-type E. coli to nalidixic acid and ciprofloxacin was higher in food-producing animals than in companion or zoo animals. Globally, we detected two qnrS1 and two aac(6')-Ib-cr in E. coli isolates recovered from animals of different origins. The genomic characterization of QnrS1-producing E. coli showed high genomic similarity (O86:H12 and ST2297), although they have been recovered from a healthy turtle dove from a Zoo Park, and from a dog showing symptoms of infection. The qnrS1 gene was encoded in a IncN plasmid, also carrying bla TEM-1-containing Tn3. Isolates harboring aac(6')-Ib-cr were detected in two captive bottlenose dolphins, within a time span of two years. The additional antibiotic resistance genes of the two aac(6')-Ib-cr-positive isolates (bla OXA-1, bla TEM-1,bla CTX-M-15, catB3, aac(3)-IIa, and tetA) were enclosed in IncFIA plasmids that differed in a single transposase and 60 single nucleotide variants. The isolates could be assigned to the same genetic sublineage-ST131 fimH30-Rx (O25:H4), confirming clonal spread. PMQR-producing isolates were associated with symptomatic and asymptomatic hosts, which highlight the aptitude of E. coli to act as silent vehicles, allowing the accumulation

  11. Klebsiella pneumoniae clinical isolate coproducing SHV-2a, DHA-1, QnrB4, and AAC(6')-Ib-cr determinants in France.

    PubMed

    Corvec, Stéphane; Crémet, Lise; Caroff, Nathalie; Dauvergne, Sandie; Le Floch, Ronan; Reynaud, Alain; Lepelletier, Didier; Bémer, Pascale

    2009-08-01

    We report on a Klebsiella pneumoniae clinical isolate coproducing bla(DHA-1), bla(SHV-2a), qnrB4, and aac(6')-Ib-cr genes. Molecular analysis demonstrated the presence of this combination on the same large plasmid. Despite a negative result for extended-spectrum beta-lactamase (ESBL) by Vitek2(R) system (bioMérieux, Marcy-l'Etoile, France), an ESBL was detected by a double-disk test. Phenotypic techniques and molecular analysis are key approaches to determine coresistance. PMID:19631103

  12. Molecular Survey of Concrete Biofilm Microbial Communities

    EPA Science Inventory

    Although several studies have shown that bacteria can deteriorate concrete structures, there is very little information on the composition of concrete microbial communities. To this end, we studied different microbial communities associated with concrete biofilms using 16S rRNA g...

  13. RADON GENERATION AND TRANSPORT IN AGED CONCRETE

    EPA Science Inventory

    The report gives results of a characterization of radon generation and transport in Florida concretes sampled from 12- to 45-year-old residential slabs. It also compares measurements from old concrete samples to previous measurements on newly poured Florida residential concretes....

  14. 9 CFR 91.26 - Concrete flooring.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Concrete flooring. 91.26 Section 91.26... LIVESTOCK FOR EXPORTATION Inspection of Vessels and Accommodations § 91.26 Concrete flooring. (a) Pens aboard an ocean vessel shall have a 3 inch concrete pavement, proportioned and mixed to give 2000...

  15. 9 CFR 91.26 - Concrete flooring.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Concrete flooring. 91.26 Section 91.26... LIVESTOCK FOR EXPORTATION Inspection of Vessels and Accommodations § 91.26 Concrete flooring. (a) Pens aboard an ocean vessel shall have a 3 inch concrete pavement, proportioned and mixed to give 2000...

  16. Lightweight concrete with enhanced neutron shielding

    DOEpatents

    Brindza, Paul Daniel; Metzger, Bert Clayton

    2016-09-13

    A lightweight concrete containing polyethylene terephthalate in an amount of 20% by total volume. The concrete is enriched with hydrogen and is therefore highly effective at thermalizing neutrons. The concrete can be used independently or as a component of an advanced neutron radiation shielding system.

  17. Evaluation of ilmenite serpentine concrete and ordinary concrete as nuclear reactor shielding

    NASA Astrophysics Data System (ADS)

    Abulfaraj, Waleed H.; Kamal, Salah M.

    1994-07-01

    The present study involves adapting a formal decision methodology to the selection of alternative nuclear reactor concretes shielding. Multiattribute utility theory is selected to accommodate decision makers' preferences. Multiattribute utility theory (MAU) is here employed to evaluate two appropriate nuclear reactor shielding concretes in terms of effectiveness to determine the optimal choice in order to meet the radiation protection regulations. These concretes are Ordinary concrete (O.C.) and Ilmenite Serpentile concrete (I.S.C.). These are normal weight concrete and heavy heat resistive concrete, respectively. The effectiveness objective of the nuclear reactor shielding is defined and structured into definite attributes and subattributes to evaluate the best alternative. Factors affecting the decision are dose received by reactor's workers, the material properties as well as cost of concrete shield. A computer program is employed to assist in performing utility analysis. Based upon data, the result shows the superiority of Ordinary concrete over Ilmenite Serpentine concrete.

  18. Concrete Finisher Program. Apprenticeship Training.

    ERIC Educational Resources Information Center

    Alberta Learning, Edmonton. Apprenticeship and Industry Training.

    This document presents information about the apprenticeship training program of Alberta, Canada, in general and the concrete finishing program in particular. The first part of the document discusses the following items: Alberta's apprenticeship and industry training system; the apprenticeship and industry training committee structure; local…

  19. Quick-setting concrete and a method for making quick-setting concrete

    DOEpatents

    Wagh, Arun S.; Singh, Dileep; Pullockaran, Jose D.; Knox, Lerry

    1997-01-01

    A method for producing quick setting concrete is provided comprising hydrng a concrete dry mixture with carbonate solution to create a slurry, and allowing the slurry to cure. The invention also provides for a quick setting concrete having a predetermined proportion of CaCO.sub.3 of between 5 and 23 weight percent of the entire concrete mixture, and whereby the concrete has a compression strength of approximately 4,000 pounds per square inch (psi) within 24 hours after pouring.

  20. Root aeration improves growth and nitrogen accumulation in rice seedlings under low nitrogen.

    PubMed

    Zhu, Jingwen; Liang, Jing; Xu, Zhihui; Fan, Xiaorong; Zhou, Quansuo; Shen, Qirong; Xu, Guohua

    2015-11-16

    In wetland soils, changes in oxygen (O2) level in the rhizosphere are believed to influence the behaviour of nutrients and their usage by plants. However, the effect of aeration on nitrogen (N) acquisition under different N supply conditions remains largely unknown. In this study, the rice cultivars Yangdao 6 (YD6, with higher root aerenchyma abundance) and Nongken 57 (NK57, with lower root aerenchyma abundance) were used to evaluate the effects of aeration on rice growth and N accumulation. Our results showed that the number of adventitious roots and the root surface area increased significantly, and ethylene production and aerenchyma formation decreased in both cultivars after external aeration (EA). Five N treatments, including no N (-N), 0.125 mM NH4NO3 (LN), 1.25 mM Ca(NO3)2 (NO3-N), 1.25 mM (NH4)2SO4 (NH4-N) and 1.25 mM NH4NO3 (N/N), were applied to YD6 and NK57 for 2 days under internal aeration or EA conditions. External aeration increased the root biomass in both cultivars and the shoot biomass in NK57 by 18-50 %. The total N concentrations in roots of YD6 grown under -N and LN and of NK57 grown under NO3-N were increased by EA. Expression of OsPAD4, one of four putative genes regulating aerenchyma formation, showed a similar pattern alongside changes in the ethylene level in the EA-treated rice irrespective of the N treatments. Furthermore, expression of the high-affinity nitrate transporter gene OsNRT2.1 was increased by EA under -N, LN and NO3-N conditions. Our data provide evidence of an interaction between O2 and the supply of N in ethylene production, aerenchyma formation and N nutrition through modification of the expression of OsPAD4 and OsNRT2.1.

  1. Root aeration improves growth and nitrogen accumulation in rice seedlings under low nitrogen

    PubMed Central

    Zhu, Jingwen; Liang, Jing; Xu, Zhihui; Fan, Xiaorong; Zhou, Quansuo; Shen, Qirong; Xu, Guohua

    2015-01-01

    In wetland soils, changes in oxygen (O2) level in the rhizosphere are believed to influence the behaviour of nutrients and their usage by plants. However, the effect of aeration on nitrogen (N) acquisition under different N supply conditions remains largely unknown. In this study, the rice cultivars Yangdao 6 (YD6, with higher root aerenchyma abundance) and Nongken 57 (NK57, with lower root aerenchyma abundance) were used to evaluate the effects of aeration on rice growth and N accumulation. Our results showed that the number of adventitious roots and the root surface area increased significantly, and ethylene production and aerenchyma formation decreased in both cultivars after external aeration (EA). Five N treatments, including no N (−N), 0.125 mM NH4NO3 (LN), 1.25 mM Ca(NO3)2 (NO3-N), 1.25 mM (NH4)2SO4 (NH4-N) and 1.25 mM NH4NO3 (N/N), were applied to YD6 and NK57 for 2 days under internal aeration or EA conditions. External aeration increased the root biomass in both cultivars and the shoot biomass in NK57 by 18–50 %. The total N concentrations in roots of YD6 grown under −N and LN and of NK57 grown under NO3-N were increased by EA. Expression of OsPAD4, one of four putative genes regulating aerenchyma formation, showed a similar pattern alongside changes in the ethylene level in the EA-treated rice irrespective of the N treatments. Furthermore, expression of the high-affinity nitrate transporter gene OsNRT2.1 was increased by EA under −N, LN and NO3-N conditions. Our data provide evidence of an interaction between O2 and the supply of N in ethylene production, aerenchyma formation and N nutrition through modification of the expression of OsPAD4 and OsNRT2.1. PMID:26578743

  2. Microbiologically induced deterioration of concrete - A Review

    PubMed Central

    Wei, Shiping; Jiang, Zhenglong; Liu, Hao; Zhou, Dongsheng; Sanchez-Silva, Mauricio

    2013-01-01

    Microbiologically induced deterioration (MID) causes corrosion of concrete by producing acids (including organic and inorganic acids) that degrade concrete components and thus compromise the integrity of sewer pipelines and other structures, creating significant problems worldwide. Understanding of the fundamental corrosion process and the causal agents will help us develop an appropriate strategy to minimize the costs in repairs. This review presents how microorganisms induce the deterioration of concrete, including the organisms involved and their colonization and succession on concrete, the microbial deterioration mechanism, the approaches of studying MID and safeguards against concrete biodeterioration. In addition, the uninvestigated research area of MID is also proposed. PMID:24688488

  3. Diffusion of Radionuclides in Concrete and Soil

    SciTech Connect

    Mattigod, Shas V.; Wellman, Dawn M.; Bovaird, Chase C.; Parker, Kent E.; Recknagle, Kurtis P.; Clayton, Libby N.; Wood, Marcus I.

    2012-04-25

    One of the methods being considered for safely disposing of Category 3 low-level radioactive wastes is to encase the waste in concrete. Such concrete encasement would contain and isolate the waste packages from the hydrologic environment and would act as an intrusion barrier. Any failure of concrete encasement may result in water intrusion and consequent mobilization of radionuclides from the waste packages. The mobilized radionuclides may escape from the encased concrete by mass flow and/or diffusion and move into the surrounding subsurface environment. Therefore, it is necessary to assess the performance of the concrete encasement structure and the ability of the surrounding soil to retard radionuclide migration. The objective of our study was to measure the diffusivity of Re, Tc and I in concrete containment and the surrounding vadose zone soil. Effects of carbonation, presence of metallic iron, and fracturing of concrete and the varying moisture contents in soil on the diffusivities of Tc and I were evaluated.

  4. Towards understanding the kinetic behaviour and limitations in photo-induced copper(I) catalyzed azide-alkyne cycloaddition (CuAAC) reactions

    PubMed Central

    El-Zaatari, Bassil M.; Shete, Abhishek U.; Adzima, Brian J.; Kloxin, Christopher J.

    2016-01-01

    The kinetic behaviour of the photo-induced copper(I) catalyzed azide—alkyne cycloaddition (CuAAC) reaction was studied in detail using real-time Fourier Transform Infrared Spectroscopy (FTIR) on both a solvent-based monofunctional and a neat polymer network forming system. The results in the solvent-based system showed near first-order kinetics on copper and photoinitiator concentrations up to a threshold value in which the kinetics switch to zeroth-order. This kinetic shift shows that the photo-CuAAC reaction is not suseptible from side reactions such as copper disproportionation, copper(I) reduction, and radical termination at the early stages of the reaction. The overall reaction rate and conversion is highly dependent on the initial concentrations of photoinitiator and copper(II), as well as their relative ratios. The conversion was decreased when an excess of photoinitiator was utilized compared to its threshold value. Interestingly, the reaction showed an induction period at relatively low intensities. The induction period is decreased by increasing light intensity, and photoinitiator concentration. The reaction trends and limitations were further observed in a solventless polymer network forming system, exhibiting a similar copper and photoinitiator threshold behaviour. PMID:27711587

  5. Eina! Ouch! Eish! Professionals' Perceptions of How Children with Cerebral Palsy Communicate About Pain in South African School Settings: Implications for the use of AAC.

    PubMed

    Johnson, Ensa; Nilsson, Stefan; Adolfsson, Margareta

    2015-01-01

    Most children with severe cerebral palsy experience daily pain that affects their school performance. School professionals need to assess pain in these children, who may also have communication difficulties, in order to pay attention to the pain and support the children's continued participation in school. In this study, South African school professionals' perceptions of how they observed pain in children with cerebral palsy, how they questioned them about it and how the children communicated their pain back to them were investigated. Thirty-eight school professionals participated in five focus groups. Their statements were categorized using qualitative content analysis. From the results it became clear that professionals observed children's pain communication through their bodily expressions, behavioral changes, and verbal and non-verbal messages. Augmentative and alternative communication (AAC) methods were rarely used. The necessity of considering pain-related vocabulary in a multilingual South African context, and of advocating for the use of AAC strategies to enable children with cerebral palsy to communicate their pain was highlighted in this study. PMID:26372118

  6. Eina! Ouch! Eish! Professionals' Perceptions of How Children with Cerebral Palsy Communicate About Pain in South African School Settings: Implications for the use of AAC.

    PubMed

    Johnson, Ensa; Nilsson, Stefan; Adolfsson, Margareta

    2015-01-01

    Most children with severe cerebral palsy experience daily pain that affects their school performance. School professionals need to assess pain in these children, who may also have communication difficulties, in order to pay attention to the pain and support the children's continued participation in school. In this study, South African school professionals' perceptions of how they observed pain in children with cerebral palsy, how they questioned them about it and how the children communicated their pain back to them were investigated. Thirty-eight school professionals participated in five focus groups. Their statements were categorized using qualitative content analysis. From the results it became clear that professionals observed children's pain communication through their bodily expressions, behavioral changes, and verbal and non-verbal messages. Augmentative and alternative communication (AAC) methods were rarely used. The necessity of considering pain-related vocabulary in a multilingual South African context, and of advocating for the use of AAC strategies to enable children with cerebral palsy to communicate their pain was highlighted in this study.

  7. Synthesis of alpha- and beta-D-glucopyranosyl triazoles by CuAAC 'click chemistry': reactant tolerance, reaction rate, product structure and glucosidase inhibitory properties.

    PubMed

    Dedola, Simone; Hughes, David L; Nepogodiev, Sergey A; Rejzek, Martin; Field, Robert A

    2010-06-16

    Cu(I)-catalysed azide alkyne 1,3-dipolar cycloaddition (CuAAC) 'click chemistry' was used to assemble a library of 21 alpha-D- and beta-D-glucopyranosyl triazoles, which were assessed as potential glycosidase inhibitors. In the course of this work, different reactivities of isomeric alpha- and beta-glucopyranosyl azides under CuAAC conditions were noted. This difference was further investigated using competition reactions and rationalised on the basis of X-ray crystallographic data, which revealed significant differences in bond lengths within the azido groups of the alpha- and beta-anomers. Structural studies also revealed a preference for perpendicular orientation of the sugar and triazole rings in both the alpha- and beta-glucosyl triazoles in the solid state. The triazole library was assayed for inhibition of sweet almond beta-glucosidase (GH1) and yeast alpha-glucosidase (GH13), which led to the identification of a set of glucosidase inhibitors effective in the 100 microM range. The preference for inhibition of one enzyme over the other proved to be dependent on the anomeric configuration of the inhibitor, as expected.

  8. Preparation, properties and biological application of pH-sensitive poly(ethylene oxide) (PEO) hydrogels grafted with acrylic acid(AAc) using gamma-ray irradiation

    NASA Astrophysics Data System (ADS)

    Nho, Young Chang; Mook Lim, Youn; Moo Lee, Young

    2004-09-01

    pH-sensitive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing it in the small intestine. In this study, hydrogels based on poly(ethylene oxide) (PEO) networks grafted with acrylic acid (AAc) were prepared via a two-step process. PEO hydrogels were prepared by γ-ray irradiation, and then grafting by AAc monomer onto the PEO hydrogels with the subsequent irradiation (radiation dose: 5-20 kGy, dose rate: 2.15 kGy/h). These grafted hydrogels showed a pH-sensitive swelling behavior. The grafted hydrogels were used as a carrier for the drug delivery systems for the controlled release of insulin. The in vitro drug release behaviors of these hydrogels were examined by quantification analysis with a UV/VIS spectrophotometer. Insulin was loaded into freeze-dried hydrogels (7 mm×3 mm×2.5 mm) and administrated orally to healthy and diabetic Wistar rats. The oral administration of insulin-loaded hydrogels to Wistar rats decreased the blood glucose levels obviously for at least 4 h due to the absorption of insulin in the gastrointestinal tract.

  9. Eina! Ouch! Eish! Professionals’ Perceptions of How Children with Cerebral Palsy Communicate About Pain in South African School Settings: Implications for the use of AAC

    PubMed Central

    Johnson, Ensa; Nilsson, Stefan; Adolfsson, Margareta

    2015-01-01

    Abstract Most children with severe cerebral palsy experience daily pain that affects their school performance. School professionals need to assess pain in these children, who may also have communication difficulties, in order to pay attention to the pain and support the children’s continued participation in school. In this study, South African school professionals’ perceptions of how they observed pain in children with cerebral palsy, how they questioned them about it and how the children communicated their pain back to them were investigated. Thirty-eight school professionals participated in five focus groups. Their statements were categorized using qualitative content analysis. From the results it became clear that professionals observed children’s pain communication through their bodily expressions, behavioral changes, and verbal and non-verbal messages. Augmentative and alternative communication (AAC) methods were rarely used. The necessity of considering pain-related vocabulary in a multilingual South African context, and of advocating for the use of AAC strategies to enable children with cerebral palsy to communicate their pain was highlighted in this study. PMID:26372118

  10. Coupling of bio-PRB and enclosed in-well aeration system for remediation of nitrobenzene and aniline in groundwater.

    PubMed

    Liu, Na; Ding, Feng; Wang, Liu; Liu, Peng; Yu, Xiaolong; Ye, Kang

    2016-05-01

    A laboratory-scale bio-permeable reactive barrier (bio-PRB) was constructed and combined with enclosed in-well aeration system to treat nitrobenzene (NB) and aniline (AN) in groundwater. Batch-style experiments were first conducted to evaluate the effectiveness of NB and AN degradation, using suspension (free cells) of degrading consortium and immobilized consortium by a mixture of perlite and peat. The NB and AN were completely degraded in <3 days using immobilized consortium, while 3-5 days were required using free cells. The O2 supply efficiency of an enclosed in-well aeration system was assessed in a box filled with perlite and peat. Dissolved O2 (DO) concentrations increased to 8-12 mg L(-1) in 12 h for sampling ports within 12 cm of the aeration well. A diffusion coefficient as 33.5 cm(2) s(-1) was obtained. The DO concentration was >4 mg L(-1) when the aeration system was applied into the bio-PRB system. The NB and AN were effectively removed when the aeration system was functional in the bio-PRB. The removal efficiency decreased when the aeration system malfunctioned for 20 days, thus indicating that DO was an important factor for the degradation of NB and AN. The regain of NB and AN removal after the malfunction indicates the robustness of degradation consortium. No original organics and new formed by-products were observed in the effluent. The results indicate that NB and AN in groundwater can be completely mineralized in a bio-PRB equipped with enclosed in-well aeration system and filled with perlite and peat attached with degrading consortium.

  11. Changes in the chemical and physicochemical properties of the solid fraction of cattle slurry during composting using different aeration strategies.

    PubMed

    Cáceres, Rafaela; Flotats, Xavier; Marfà, Oriol

    2006-01-01

    Replacement of peat as a growing medium by a renewable material, such as an organic waste, is an issue of concern since harvesting of peat has a considerable environmental impact and, actually, it is a non-renewable resource. Cattle manure is a readily available organic waste, which means that once it goes through the composting process, it can be used as an alternative to peat, specifically, the solid fraction obtained from mechanical liquid-solid separation of cattle slurry (SF). Studies have shown it to be suitable for such uses. The purpose of this study was to detect possible changes in the physicochemical and chemical properties of SF when it is composted using different aeration strategies, with an emphasis on the changes that would make it feasible for use as a substrate. With this aim in mind, an experiment was designed with three aeration strategies that would be used during composting. The first consisted of applying air through a static method (forced ventilation). The second involved improving aeration by adding a bulking agent and a dynamic turning method. In the third strategy, aeration was carried out by turning (control). The results show that the different aeration strategies had a clear effect on the evolution of pH, electrical conductivity (EC), nitrate-N, ammonia-N and bicarbonate content. Nitrification was favored under good aeration conditions using the static composting method, probably due to the greater availability of ammonia-N that was transformed into nitrate-N. In general, the low buffering capacity allowed for a reduction of the pH during the curing stage of composting (in conjunction with low temperatures during this period), a characteristic that favors the use of this compost as a growing medium. We also conclude that measuring bicarbonate levels during composting could be used as an indicator of the possible acidification of the material and as a way of evaluating the level of material aeration. PMID:16146687

  12. Changes in the chemical and physicochemical properties of the solid fraction of cattle slurry during composting using different aeration strategies.

    PubMed

    Cáceres, Rafaela; Flotats, Xavier; Marfà, Oriol

    2006-01-01

    Replacement of peat as a growing medium by a renewable material, such as an organic waste, is an issue of concern since harvesting of peat has a considerable environmental impact and, actually, it is a non-renewable resource. Cattle manure is a readily available organic waste, which means that once it goes through the composting process, it can be used as an alternative to peat, specifically, the solid fraction obtained from mechanical liquid-solid separation of cattle slurry (SF). Studies have shown it to be suitable for such uses. The purpose of this study was to detect possible changes in the physicochemical and chemical properties of SF when it is composted using different aeration strategies, with an emphasis on the changes that would make it feasible for use as a substrate. With this aim in mind, an experiment was designed with three aeration strategies that would be used during composting. The first consisted of applying air through a static method (forced ventilation). The second involved improving aeration by adding a bulking agent and a dynamic turning method. In the third strategy, aeration was carried out by turning (control). The results show that the different aeration strategies had a clear effect on the evolution of pH, electrical conductivity (EC), nitrate-N, ammonia-N and bicarbonate content. Nitrification was favored under good aeration conditions using the static composting method, probably due to the greater availability of ammonia-N that was transformed into nitrate-N. In general, the low buffering capacity allowed for a reduction of the pH during the curing stage of composting (in conjunction with low temperatures during this period), a characteristic that favors the use of this compost as a growing medium. We also conclude that measuring bicarbonate levels during composting could be used as an indicator of the possible acidification of the material and as a way of evaluating the level of material aeration.

  13. The use of an aeration system to prevent thermal stratification of a freshwater impoundment and its effect on downstream fish assemblages.

    PubMed

    Miles, N G; West, R J

    2011-03-01

    Warm-water riverine fish assemblages were investigated downstream of an impoundment before and after thermal stratification and the associated cold-water pollution was prevented using an aeration system. Temperatures below the dam significantly increased after installation of the aeration system and this correlated with an increased abundance and greater number of species downstream. Overall, aeration appeared to be beneficial for both the lake (upstream) and the downstream riverine environments.

  14. Structure of the bifunctional aminoglycoside-resistance enzyme AAC(6′)-Ie-APH(2′′)-Ia revealed by crystallographic and small-angle X-ray scattering analysis

    PubMed Central

    Smith, Clyde A.; Toth, Marta; Weiss, Thomas M.; Frase, Hilary; Vakulenko, Sergei B.

    2014-01-01

    Broad-spectrum resistance to aminoglycoside antibiotics in clinically important Gram-positive staphylococcal and entero­coccal pathogens is primarily conferred by the bifunctional enzyme AAC(6′)-Ie-APH(2′′)-Ia. This enzyme possesses an N-terminal coenzyme A-dependent acetyltransferase domain [AAC(6′)-Ie] and a C-terminal GTP-dependent phosphotransferase domain [APH(2′′)-Ia], and together they produce resistance to almost all known aminoglycosides in clinical use. Despite considerable effort over the last two or more decades, structural details of AAC(6′)-Ie-APH(2′′)-Ia have remained elusive. In a recent breakthrough, the structure of the isolated C-terminal APH(2′′)-Ia enzyme was determined as the binary Mg2GDP complex. Here, the high-resolution structure of the N-terminal AAC(6′)-Ie enzyme is reported as a ternary kanamycin/coenzyme A abortive complex. The structure of the full-length bifunctional enzyme has subsequently been elucidated based upon small-angle X-ray scattering data using the two crystallographic models. The AAC(6′)-Ie enzyme is joined to APH(2′′)-Ia by a short, predominantly rigid linker at the N-terminal end of a long α-helix. This α-helix is in turn intrinsically associated with the N-terminus of APH(2′′)-Ia. This structural arrangement supports earlier observations that the presence of the intact α-helix is essential to the activity of both functionalities of the full-length AAC(6′)-Ie-APH(2′′)-Ia enzyme. PMID:25286858

  15. Remediation of Urban River Water by Pontederia Cordata Combined with Artificial Aeration: Organic Matter and Nutrients Removal and Root-Adhered Bacterial Communities.

    PubMed

    Gu, Dungang; Xu, Huan; He, Yan; Zhao, Feng; Huang, Minsheng

    2015-01-01

    Macrophyte combined with artificial aeration is a promising in situ remediation approach for urban rivers polluted with nutrients and organic matter. However, seasonal variations and aeration effects on phytoremediation performance and root-adhered microbial communities are still unclear. In this study, Pontederia cordata was used to treat polluted urban river water under various aeration intensities. Results showed that the highest removal efficiencies of chemical oxygen demand (COD(Cr)) and total nitrogen (TN) were attained under aeration of 30 L min(-1) in spring and summer and 15 L min(-1) in autumn, while total phosphorus (TP) removal reached maximum with aeration of 15 L min(-1) in all seasons. Moderate aeration was beneficial for increasing the diversity of root-adhered bacteria communities, and the shift of bacterial community structure was more pronounced in spring and autumn with varying aeration intensity. The dual effect, i.e. turbulence and dissolved oxygen (DO), of aeration on the removal of COD(Cr) and TN prevailed over the individual effect of DO, while DO was the most influential factor for TP removal and the root-adhered bacterial community diversity. P. cordata combined with 15 L min(-1) aeration was deemed to be the best condition tested in this study.

  16. Fracture properties of lightweight concrete

    SciTech Connect

    Chang, T.P.; Shieh, M.M.

    1996-02-01

    This study presents the experimental results of fracture properties of concrete incorporating two kinds of domestic lightweight aggregate (LWA) manufactured through either a cold-bonding or a sintering process. The cold-bonded aggregates were mainly made of pulverized fly-ash through a cold-pelletization process at ambient temperature, while the sintered aggregates were made of clay and shale expanded by heat at a temperature near 1,200 C. Experimental results show that the 28-day compressive strengths of {phi} 100 x 200 mm cylindrical concrete specimen made of those LWAs range from 30.1 (sintered) to 33.9 MPa (cold-bonded). By means of size effect law, it is found that the fracture energies, G{sub f}, were 34.42 N/m (sintered) and 37.2 N/m (cold-bonded), respectively.

  17. Radionuclide Retention in Concrete Wasteforms

    SciTech Connect

    Bovaird, Chase C.; Jansik, Danielle P.; Wellman, Dawn M.; Wood, Marcus I.

    2011-09-30

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. The information present in the report provides data that (1) measures the effect of concrete wasteform properties likely to influence radionuclide migration; and (2) quantifies the rate of carbonation of concrete materials in a simulated vadose zone repository.

  18. The effect of aeration and recirculation on a sand-based hybrid constructed wetland treating low-strength domestic wastewater.

    PubMed

    Zapater-Pereyra, M; Kyomukama, E; Namakula, V; van Bruggen, J J A; Lens, P N L

    2016-08-01

    The Duplex-constructed wetland (CW) is a hybrid system composed of a vertical flow (VF) CW on top of a horizontal flow filter (HFF). Each compartment is designed to play a different role: aerobic treatment in the VF CW due to intermittent feeding and anoxic treatment in the HFF due to saturated conditions. Three Duplex-CWs were used in this study: Control, Aerated and Recirculating. The role of each compartment was tested for pollutant removal and micro-invertebrate abundance. In all systems, the VF CW removed mainly organic matter, solids and NH4(+)-N. Pathogens were removed in both compartments. Likewise, total nitrogen removal occurred in both compartments, only the Recirculating HFF was not able to denitrify the nitrogen due to the slightly more oxic conditions as compared to the other systems. All systems met discharge guidelines for organic matter, but only the Control and Aerated systems met those for total nitrogen. At the applied loading rates, the pollutant removal was not significantly enhanced by the use of aeration and recirculation. Therefore, operation as in the Control system, without aeration or recirculation, is recommended for the tested Duplex-CWs. If artificial aeration will be used in CWs, the support material should be carefully selected to allow a proper air distribution. PMID:26732367

  19. Nitrogen and carbon removal from synthetic wastewater in a vertical structured-bed reactor under intermittent aeration.

    PubMed

    Moura, Rafael B; Damianovic, Márcia H R Z; Foresti, Eugenio

    2012-05-15

    The removal of nitrogen and organic matter using a single reactor has been a common focus of investigation, and reactors operated in batch mode and under intermittent aeration have attracted special attention. This study aimed to evaluate the application of a new reactor configuration consisting of a fixed-bed reactor that was operated under conditions of continuous feeding and intermittent aeration. The reactor was built using acrylic, with a working volume of 6.1L. The fixed bed used for biomass support was composed of polyurethane foam cylinders vertically oriented inside the reaction zone. The reactor was operated under intermittent aeration (2h aerated and 1h non-aerated) and a recirculation ratio Q(r)/Q=5. Three different operating conditions (Phase I, Phase II, and Phase III) corresponding to hydraulic retention times (HRT) of 12h, 8h, and 10h, respectively, were tested. In Phase I, the system achieved total nitrogen (TN) and chemical oxygen demand (COD) removal efficiencies of 82% and 89%, respectively. At HRTs of 8 h and 10 h, the reactor was unstable with respect to TN removal, and the average resultant removal efficiencies were 49% and 45%, respectively. However, COD removal efficiencies remained high with mean values of 85% and 88% for Phases II and III, respectively. Based on these results, it can be concluded that this new reactor configuration constitutes an alternative method for effective removal of organic matter and nitrogen from wastewater.

  20. Internal aeration of paddy field rice (Oryza sativa) during complete submergence---importance of light and floodwater O2.

    PubMed

    Winkel, Anders; Colmer, Timothy D; Ismail, Abdelbagi M; Pedersen, Ole

    2013-03-01

    Flash floods can submerge paddy field rice (Oryza sativa), with adverse effects on internal aeration, sugar status and survival. Here, we investigated the in situ aeration of roots of rice during complete submergence, and elucidated how underwater photosynthesis and floodwater pO(2) influence root aeration in anoxic soil. In the field, root pO(2) was measured using microelectrodes during 2 d of complete submergence. Leaf gas films that formed on the superhydrophobic leaves were left intact, or experimentally removed, to elucidate their effect on internal aeration. In darkness, root pO(2) declined to very low concentrations (0.24 kPa) and was strongly correlated with floodwater pO(2). In light, root pO(2) was high (14 kPa) and primarily a function of the incident light determining the rates of underwater net photosynthesis. Plants with intact leaf gas films maintained higher underwater net photosynthesis relative to plants without gas films when the submerged shoots were in light. During complete submergence, internal aeration of rice in the field relies on underwater photosynthesis during the day and entry of O(2) from the floodwater during the night. Leaf gas films enhance photosynthesis during submergence leading to improved O(2) production and sugar status, and therefore contribute to the submergence tolerance of rice.