1,721,021 research outputs found
Network slicing and softwarization: A survey on principles, enabling technologies and solutions
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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
Green Inhibition of Mild Steel Corrosion in a CO2 Saturated Saline Solution
No full textA Master of Science thesis in Chemical Engineering by Elron Edgar Gomes entitled, "Green Inhibition of Mild Steel Corrosion in a CO2 Saturated Saline Solution," submitted in May 2015. Thesis advisor is Dr. Taleb Ibrahim. Soft and hard copy available.Mild steel is extensively used in equipment such as pipelines and machinery by many industries, where it is exposed to corrosive environments. Dissolved carbon dioxide (CO2) can be found in produced water and results in severe corrosion due to the formation of carbonic acid. CO2 corrosion presents not only an economic loss but also an environmental and safety risk. Most industries use synthetic inhibitors, which are effective in reducing corrosion, but are also toxic and persistent. This has led to stricter regulations and thus, there is a need for alternative inhibitors which can replace them but not exhibit their undesired characteristics. The aqueous extracts of Fig leaves (FLE), Calotropis procera (CPLE) and Eggplant peels (EPPE) were investigated as novel corrosion inhibitors for mild steel in a CO2-saturated 3.5wt% NaCl solution using various electrochemical techniques such as linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS) and cyclic sweep (CS). The results showed that the corrosion rate is decreasing and inhibition efficiency is increasing as the concentration of inhibitor increased. Corrosion inhibition efficiencies of 90-95% were obtained using low dosage of the green inhibitors. FLE, CPLE and EPPE proved to be effective inhibitors and are compared to the performance of two commercially available inhibitors, A (green inhibitor) and B (synthetic inhibitor). Polarization studies show that FLE, CPLE and EPPE act as mixed inhibitors. The adsorption data was analyzed using various adsorption isotherm models and the results at temperatures of 25, 40, 50 and 70°C have shown that the adsorption behavior of FLE, CPLE and EPPE is best described by the Langmuir adsorption isotherm. The conclusion drawn from this work is that the FLE, CLE and ELE inhibitors proved to be effective inhibitors when compared to Inhibitor A. Inhibitor B proved to be a much more effective inhibitor than the others due to its synergistic mix of active ingredients.College of EngineeringDepartment of Chemical EngineeringMaster of Science in Chemical Engineering (MSChE
Removal of Heavy Metals from Wastewater Using Multiwalled Carbon Nanotubes
No full textA Master of Science thesis in Chemical Engineering by Malaz Suliman entitled, "Removal of Heavy Metals from Wastewater Using Multiwalled Carbon Nanotubes," submitted in April 2017. Thesis advisor is Dr. Taleb Ibrahim. Soft and hard copy available.Recently, carbon nanotubes have been employed as new adsorbent for the removal of many pollutants. In this study, raw multiwalled carbon nanotubes (MWCNTs) were firstly tested for the removal of lead from aqueous solutions. Then, sodium lauryl sulfate modified multiwalled carbon nanotubes (SLS-MWCNTs) were produced, characterized and used for lead removal. Surface characterization using energy dispersive X-ray spectroscopy (EDS), thermogravimetric analyzer (TGA) and Fourier transform infrared spectroscopy (FTIR) showed that surface modification has been achieved successfully. Adsorption results revealed that the surface modification has increased the adsorption capacity from 3.84 mg/g for raw-MWCNTs to 141 mg/g for SLS-MWCNTs. On the other hand, the optimum values of some important parameters were determined. Optimum values of adsorbent dosage, contact time, pH and temperature using raw-MWCNTs were found to be 15.0 g/L, 50 min, 6.5 and 25 °C, respectively and for the SLS-MWCNTs the optimum parameters were found to be 3.00 g/L, 30 min, 5.3 and 25 °C, respectively. Fitting equilibrium data on different isotherm models showed that adsorption on raw-MWCNTs follows Langmuir model with qm = 3.84 mg/g and KL = 0.29 L/mg, while adsorption on SLS-MWCNTs is best described by Freundlich model with n = 2.50 and KF = 15.40 (mg0.6. L0.4)/g. Furthermore, kinetics study results revealed that both raw and SLS-MWCNTs follow the pseudo second order model with rate constants 0.11 g/mg.min and 0.06 g/mg.min, respectively. Thermodynamics study showed that mode of adsorption is physisorption on both raw and SLS-MWCNTs with ∆G values -0.45 and -9.21 kJ/mol at 25 °C, respectively. In order to get higher density particles with more granular structure to enhance column operation, magnetite pellets of SLS-MWCNTs were prepared and used in packed bed column. Column data were found to fit well by the modified dose response model with parameters values qmdr = 28.4 mg/g and a' = 3.47 mg-1.College of EngineeringDepartment of Chemical EngineeringMaster of Science in Chemical Engineering (MSChE
Removal of Lead (II) Ions from Wastewater Using Eggplant Peels
No full textA Master of Science thesis in Chemical Engineering by Zaeem Bin Babar entitled, "Removal of Lead (II) Ions from Wastewater Using Eggplant Peels," submitted in January 2013. Thesis advisor is Dr. Taleb Hassan Ibrahim. Available are both soft and hard copies of the thesis.In this study, three methods have been tested for the production of eggplant peel activated charcoal (EPPAC) from eggplant peel charcoal (EPPC). A new method has also been devised which does not include continuous involvement of inert gas stream from any external source. Activation parameters used for the production of activated charcoal such as activation temperature, activation time have been optimized. Based upon the maximum removal efficiency of 70% for lead (II) from wastewater, EPPAC-2 (prepared by physical mixing of grinded KOH and EPPC) has been considered most efficient as compared to EPPAC-1 (prepared by the physical mixing of KOH lentils and EPPC) and EPPAC-3 (impregnation). The surface area of EPPAC-2 is 739m2/g. Surface characterization of EPPAC-2 involves the determination of physical and chemical properties such as surface structure, pH, surface area, and surface functional groups. Adsorption of lead (II) ions has been confirmed by energy dispersive X-ray spectrometry (EDS) analysis on lead (II) loaded EPPAC-2. Adsorption experiments have also been conducted for the removal of lead (II) ions from wastewater by using EPPAC-2 as adsorbent. Optimum pH, adsorbent dose and equilibrium time are 5.1, 0.32g and 24h respectively. Adsorption kinetics of lead (II) has been best described by pseudo-second-order kinetic model. The adsorption equilibrium data has been fitted by using different models such as Langmuir, Freundlich, Duninin-Radushkevich, Temkin, Toth and Langmuir-Freundlich isotherm models. Langmuir adsorption model suits best for the equilibrium data. Maximum adsorption capacity of 140.84 mg/g has been given by Langmuir isotherm model. This study demonstrates that EPPAC-2 can be used as a low cost adsorbent for the removal of lead (II) ions in water treatment. Keywords: Eggplant peel activated charcoal; Adsorption; Isotherm; Low cost adsorbent; Wastewater treatment; Heavy metalsCollege of EngineeringDepartment of Chemical EngineeringMaster of Science in Chemical Engineering (MSChE
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
Treatment of Spent Caustic Using Ionic Liquids
No full textA Master of Science thesis in Chemical Engineering by Muhammad Ashraf Sabri entitled, "Treatment of Spent Caustic Using Ionic Liquids," submitted in April 2017. Thesis advisor is Dr. Taleb Hassan Ibrahim. Soft and hard copy available.Treatment of spent caustic (SC) wastes from downstream of refineries and petrochemical industries is not only complex but also highly expensive due to its content of high concentration of hazardous compounds, high pH, variations in the waste composition and the need to comply with the environmental regulations. Owing to the presence of pollutants such as sulfides, mercaptans and phenols, SC is known to be among the most difficult class of wastes to be treated and disposed. Several existing technologies have been applied to treat SC; however, they require extreme operation conditions of pressure and temperature. These methods are neither environment friendly nor cost effective. Thus, efforts are directed toward removal of specific pollutants particularly phenols, sulfides and mercaptans from SC streams in simple and environment-friendly manner. In this work, two hydrophobic ionic liquids (IL), tetrahexylammoniumdihexyl-sulfosuccinate (IL1) and trioctylmethylammonium salicylate (IL2), were used to treat industrial SC at room temperature using both bench scale batch contactor and sequential batch contactor modes. UVVis spectroscopy, gas chromatography coupled with mass spectrometry (GC-MS) and chemical oxygen demand (COD) analysis were employed for SC characterization. The chemical composition and the COD values of SC were determined before and after treatment with IL1 and IL2. The operating conditions for extraction were optimized. The results reveal that both ionic liquids have the same optimum phase ratio and initial pH of 1.0 and 1.7, respectively. The optimum contact time for IL1 and IL2 is less than 6.0 minutes and 1.0 minute, respectively. Under these optimum conditions, IL1 and IL2 are able to reduce the COD level from 6.4x104 mg/L to 63 mg/L and the phenol level from 3.2x102 mg/L to 0.032 mg/L in SC. Thiol and benzaldehyde concentrations after treatment are brought below the detection limit of the GC-MS. Thus, this work highlights the high potential of ILs as an alternative SC treatment solution compared tothe current complex industrial processes that require drastic operation conditions, use of hazardous chemicals and long contact times for SC treatment. The results of this work assure that the use of ILS for SC treatment is highly efficient, environmentally friendly, simple and novel.College of EngineeringDepartment of Chemical EngineeringMaster of Science in Chemical Engineering (MSChE
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