1,720,976 research outputs found
Morphology controlled oxide nanostructures and their effect on biosensing capabilities and photocatalytic activity
No full textWe report the fabrication of metal oxide nanostructure grown directly on the electrode surface by electrodeposition and thermal oxidation techniques. Chemical additives were used as morphology modifying agents to obtain morphology-controlled nanostructures. These nanostructures were used as platforms for biosensing applications as well the photoelectrochemical devices. The variation in morphology strongly influenced the performance of the electrodes.
Nanomaterials have played an important role in such devices due to their unique properties. Zinc oxide (ZnO), cerium oxide (CeO₂), and copper oxide (CuO) are such promising materials and finds potential in various applications. Those nanostructures have attracted a lot of interest because of their many advantages, including high sensitivity, unique surface characteristics that influence adsorption qualities, biocompatibility, affordability, and simplicity. Additionally, they have high light absorption capability, which makes the nanostructures appealing candidates for the generation of hydrogen via photocatalytic water splitting for photoelectrochemical studies.
The nanostructures are used in electrochemical applications, in which we focused on investigating the detection of numerous analytes. The nanostructures acted as high surface area supporting platforms as well as highly reactive surfaces, enhancing adsorption and analytes detection by immobilizing the enzyme. The morphology, substrate, scalability, selectivity, and stability of the fabricated biosensors were all thoroughly studied. The morphology of nanostructures and the underlying substrates have a significant impact on the sensitivity and detection limit of biosensors, according to our findings. The development of highly responsive systems to determine the different analytes contained in human blood, food and environment are progressing rapidly. The design and development of amperometric biosensors to monitor the concentration of several clinically important analytes such as glucose, cholesterol, lactate, pesticide, and hydrogen peroxide have been studied. To assess the photoelectrochemical (PEC) properties of the nanostructures, linear sweep voltammetry (LSV) and stability measurement also was performed and investigated
Zinc Oxide Nanostructures for Heavy Metal Detection in Water
No full text"Current procedures and tests for the detection of heavy metals in water sources is expensive and tedious. However, promising alternate techniques have been discovered. A tin oxide/reduced graphene oxide nanocomposite was first used as an accurate sensing material in 2011. Since then, it has also been discovered that zinc oxide (ZnO) and certain additives can produce similar results, but at a much cheaper cost as graphene is a new and expensive material. In order to confirm and test this process, this work was performed using an electrodeposition technique to form zinc oxide nanostructures on the surface of an indium tin oxide (ITO) glass electrode. By adding certain other additives such as potassium chloride during the deposition, the ZnO morphology could be altered with the hope of creating an even more sensitive electrode. The experiment parameters were to synthesize 11 different ZnO electrodes with varying morphologies to determine which was the most sensitive. The electrodes were then individually tested using square wave anodic stripping voltammetry to see how well they could test for lead ions in an acetate buffer solution at a concentration of 3.5uM. Once data was collected, charts were made to compare results from each morphology and determine which were the most sensitive and accurate.
Lithium-ion Batteries; The Intercalation of Lithium Ions and the Plating Phenomenon in Li-ion Batteries
Get PDFLithium-ion batteries are very important nowadays. They are the most popular types of rechargeable for portable electronics, from laptops and smart phones to hybrid and electric cars. Studying the surface deformation and the intercalation phenomenon of the lithium-ions in the crystal structure of the graphite electrode play a crucial role in understanding the capacity fade in lithium-ion batteries. This report shows a study on lithium cobalt oxide/graphite pouch cells charged with two different C rates (1 and 4C) over 5 cycles. It explores the internal stresses in the battery, the plating in the battery and what is associated with it. This report investigates the changes in surface deformation while charging and discharging the Lithium-ion batteries by using two different rates of charge and discharge, 1C and 4C rates. Phase shifting curvature interferometry was performed to detect the change of surface deformation. Several questions were examined throughout this report, such as the causes of expansion and contraction of the battery during charging and discharging. Charging with 4C rate showed different data than charging with 1C rate. Cycling the cells in 4C rate resulted in large capacity losses, where in 1C, it showed less capacity losses, and evidence of Lithium-ion stripping during relaxation after charging
Direct writing of calcium phosphate/graphite nanocomposite film using laser induced graphitization of polyimides
Get PDFWe report the direct writing technique of synthesizing calcium phosphate/graphite nanocomposite using laser-induced polyimide (PI) film graphitization. Two forms of nano calcium phosphate were prepared via a mechanochemical processing technique using eggshells, calcium oxide powders and diammonium hydrogen phosphate (DHP). The processed powders were characterized using fourier transform infrared (FTIR) spectroscopy. FTIR results demonstrates that both CaO and eggshell transitions through a phase change when the material is synthesized with DHP. New C=O peak and ratio change change between Calcium carbonate and phosphate was observed by increasing the mechanochemical processing time. Calcium phosphate/graphite nanocomposites were synthesized by laser irradiation of calcium phosphate-covered polyimide surfaces. The chemical structure of the synthesized nanocomposite surfaces was characterized using Ramam spectroscopy. The surface morphology and chemical composition were imaged using SEM and EDS mapping. Four electrode resistance measurements were used to determine the surface electrical conductivity. Raman spectroscopy reveals that nanocomposite that were irradiated multiple time had a lower ID/IG ratio. Eggshell CaP based laser induced graphite (LIG) had an ID/IG ratio of 0.65 during the first time it was irradiated and 0.38 when the film was irradiated five times. Similarly, CaOCaP LIG also had a higher ID/IG ratio of 0.55 during the first layer and 0.42 on the 5th layer. Furthermore, C-O, C=O stretch modes and various 〖PO〗_4 groups were found on both variant of calcium phosphate/graphite nanocomposite. SEM results exhibited novel nuclei structures on the surface that resemble a hierarchical porous network and EDS mapping was able to illustrate Calicum and Phosphate was well synthesized while the interconnecting tubes were a mixture of Graphite, Calcium and phosphate. Sheet resistance of LIG, CaOCaP LIG, and EggCaP LIG had a sheet resistance of 103Ω∎, 85Ω∎, 54Ω∎ respectively. This technique is advantageous for the manufacturing of biosensors and bioelectronics due to the straightforward one-step direct writing process and the enhanced cell adhesion properties of the rough surface
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
Proteins and natural biopolymers as templates for inorganic nanomaterial synthesis
No full textThe synthesis of one dimensional (1D) structures, using the bottom up technique has gained much attention in the past few years. This is due to the unique advantages of the synthesis method. The bottom up synthesis route for the fabrication of 1D structures utilizes mild experimental conditions, short experimental time, relatively inexpensive precursors and does not require a precise control of process variables. Moreover, the biotemplate can be functionalized which helps in the proper positioning of the 1D structures in complex circuits. In the present work, alpha synuclein protein was used as a model template for the fabrication of metallic (silver, platinum) and semiconducting (cadmium sulfide, lead sulfide, zinc sulfide) nanowires. The lateral dimensions of the nanowires could be controlled by varying the process variables. Further, this work was extended on to a cellulose template. The cellulose template is an inexpensive template, compared to proteins, and is abundantly available in various forms. Later, the biotemplated Silica and Titania nanowires were utilized for a biosensing application. The synthesized 1D structures show promise in various fields ranging from electronics, catalysis to biosensing
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
Morphology controlled oxide nanostructures and their effect on biosensing capabilities and photocatalytic activity
Get PDFWe report the fabrication of metal oxide nanostructure grown directly on the electrode surface by electrodeposition and thermal oxidation techniques. Chemical additives were used as morphology modifying agents to obtain morphology-controlled nanostructures. These nanostructures were used as platforms for biosensing applications as well the photoelectrochemical devices. The variation in morphology strongly influenced the performance of the electrodes.
Nanomaterials have played an important role in such devices due to their unique properties. Zinc oxide (ZnO), cerium oxide (CeO₂), and copper oxide (CuO) are such promising materials and finds potential in various applications. Those nanostructures have attracted a lot of interest because of their many advantages, including high sensitivity, unique surface characteristics that influence adsorption qualities, biocompatibility, affordability, and simplicity. Additionally, they have high light absorption capability, which makes the nanostructures appealing candidates for the generation of hydrogen via photocatalytic water splitting for photoelectrochemical studies.
The nanostructures are used in electrochemical applications, in which we focused on investigating the detection of numerous analytes. The nanostructures acted as high surface area supporting platforms as well as highly reactive surfaces, enhancing adsorption and analytes detection by immobilizing the enzyme. The morphology, substrate, scalability, selectivity, and stability of the fabricated biosensors were all thoroughly studied. The morphology of nanostructures and the underlying substrates have a significant impact on the sensitivity and detection limit of biosensors, according to our findings. The development of highly responsive systems to determine the different analytes contained in human blood, food and environment are progressing rapidly. The design and development of amperometric biosensors to monitor the concentration of several clinically important analytes such as glucose, cholesterol, lactate, pesticide, and hydrogen peroxide have been studied. To assess the photoelectrochemical (PEC) properties of the nanostructures, linear sweep voltammetry (LSV) and stability measurement also was performed and investigated
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