1,720,975 research outputs found
Modeling Nutrient Uptake Process and Growth Kinetics of Duckweed Spirodela punctata 7776 for Nutrient Recovery from Swine Wastewater
No full textUse of plants for swine waste management involves the removal of nutrients from the swine wastewater by the plants and the utilization of the plant biomass for other useful purposes such as feed supplement and soil amendment. Duckweed has gained much interest for this purpose in the past decades because of its high growth rate and high protein content. The goal of this research was to study the characteristics of duckweed growth and nutrient uptake from swine wastewater in order to improve the efficiency of duckweed nutrient recovery. In the first part of this research, nutrient distribution and transport in a quiescent duckweed-covered pond containing swine lagoon liquid were investigated and described mathematically. A superior duckweed strain for total protein production in swine wastewater Spirodela punctata 7776 was used as a subject of the study. Diffusive transport of ammonium was shown to be a limiting process in nitrogen removal by duckweed plants in static ponds. In addition, a pH profile developed along the depth of the pond, creating an additional barrier to ammonia volatilization from the pond covered with a duckweed mat. In the second part of the research, growth and nutrient uptake characteristics of Spirodela punctata 7776 in artificial swine medium were examined in sterile batch cultures. Growth of Spirodela punctata 7776 corresponded to the amount of nitrogen storage in its biomass rather than the nutrient concentration in the growth medium. The relationship followed Monod-like kinetics with a maximum specific growth rate of 0.2381 g/g/d. Reduction in the specific growth rate of Spirodela punctata 7776 was observed in the culture with higher crop density, which signified the adverse effects of surface crowding. A mathematical expression to represent the effects of crop density (mass per unit area) on specific growth rate was developed, which can be used in optimization of crop density management in duckweed nutrient recovery systems
Development of a startup procedure to treat pork slaughtering wastewater using the Anaerobic Sequencing Batch Reactor (ASBR)
Get PDFThe Anaerobic Sequencing Batch Reactor (ASBR) is a new reactor design developed at Iowa State University. The system combines suspended growth with batch feeding. For a full-scale ASBR, the minimum amount of seed at startup and the time required for startup are a concern of this application. A modification to the ASBR, the Effluent Baffle System (EBS) was tested to provide traditional ASBR with the capability to reduce seed and time requirements for the startup. Thus, in addition to the traditional ASBR, the EBS has been employed to improve performance in solids separation. In this study, two laboratory-scale ASBRs were operated for a nine-month period. The EBS was applied to both ASBRs in the first run and to one ASBR in the second run. Pork slaughterhouse wastewater from the Swift Company in Marshalltown, Iowa, was used in the first run and pork slaughterhouse wastewater from the Excel Corporation in Ottumwa, Iowa, was fed to the reactors in the second run.
To correspond to the full-scale ASBR in Ottumwa, Iowa which is designed to operate at hydraulic retention time (HRT) of 18 hours, the HRT was stepwise reduced to a target of 18 hours at the end of both runs. A seed concentration of 1,000 mg/L mixed liquor suspended solids (MLSS) was deemed feasible for startup of the laboratory scale ASBR with EBS (EBS-ASBR). The EBS-ASBRs were able to achieve total chemical oxygen demand (TCOD) removal as high as 90% and 73% at the design loading stage of 18 hour HRT. High soluble chemical oxygen demand (SCOD) removal was consistent at all HRTs. An exponential-like organic loading pattern in the second run was found to be an effective scheme to reach the designated load in a shorter time than the first run. When compared to the traditional ASBR, the EBS provides for more stability of the system in terms of TCOD removal. The success of the laboratory-scale EBS-ASBR in this study indicates that future research efforts could attempt to develop a full-scale operation for testing at one site.
In the current research, it was necessary to develop an organic loading procedure that was sustainable for treatment of pork slaughtering wastewater. The ability to maneuver an organic loading procedure with the type of wastes to be processed at the startup period without over stressing the biological treatment system will be a key factor for the success of a full-scale operation. Moreover, understanding the unique characteristics of the wastewater to be treated and the chemical actions occurring during the degradation process will lead to greater success in removing the pollutants from the wastestream
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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