5 research outputs found
Parametric study of low-pressure premixed ethylene/hydrogen/oxygen flame synthesis of titania nanoparticles and their phases
No full textParametric study of operating conditions of low-pressure premixed flame (ethylene/hydrogen/oxygen) synthesis using titanium tetra-isopropoxide (TTIP) precursor is investigated, specifically examining as-synthesized nanopowder phase and properties. The Sandia SPIN code is used to simulate the synthesis flow field to guide and compare with experiments. Strategic dilution of inert gases is used to adjust the characteristic flame temperature. As-produced samples are thermally stable without any sign of phase change, as characterized using TGA and DSC, up to 500⁰C. X-ray photoelectron spectroscopy (XPS) indicates Ti4+ valence and presence of carbon (13 – 30 atomic %), with absence of Ti3+, Ti-C, and nitrogen. SEM and TEM confirm mixed micro- and nano-meter features. XRD and SAED divulge srilankite, rutile, and anatase phases produce under different experimental conditions. Temperatures ranging from 1560K to 2650K, ambient pressures from 20 to 40 torr, and burner flow velocities from 150 to 300 cm/s are investigated, producing nanoparticles ranging from 3-10nm ± 3nm with mixed srilankite and rutile titania phases. Oxygen concentration effects are also studied from equivalence ratios of 1.08 to 0.37. Fuel-lean conditions produce anatase-rutile mixed nanopowders, while fuel-rich conditions yielded srilankite-rutile mixed nanopowders. By modifying the composition of the precursor (e.g. by adding ethylene), the phase of the product can be changed, likely because of carbon-doping stabilizing a specific phase.M.S.Includes bibliographical referencesby Hadi Dharma Hali
Investigation of srilankite phase formation in low-pressure premixed flame synthesis of titania nanoparticles
No full textThe effects of experimental and simulation parameters on phase formation of TiO2 nanoparticles in metalorganic-precursor-seeded ethylene/hydrogen/oxygen burner-stabilized premixed flames impinging on a chilled substrate are investigated. Using titanium tetra-iso-propoxide (TTIP) as precursor, anatase, rutile, and srilankite phases of titania nanoparticles are produced. Experimental conditions vary temperature from 1590K to 2650K, pressure from 20 to 40 torr, equivalence ratio from 0.37 to 1.08, and burner-exit gas flow velocities from 150 to 300 cm/s. Final nanoparticle sizes range from 3-10 nm ± 3nm with mixed phases. As-produced samples are stable without any sign of subsequent phase change, as characterized using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), up to 500°C. X-ray photoelectron spectroscopy (XPS) indicates Ti4+ valence and presence of carbon (13-30 atomic %), with absence of Ti3+, Ti-C, and nitrogen. Scanning Electron Microscopy (SEM) and transmission electron microscopy (TEM) confirm mixed micro- and nano-meter features. X-ray diffraction (XRD) and selected area electron diffraction (SAED) divulge srilankite, rutile, and anatase phases produce under different experimental conditions. Qualitatively, lower equivalence ratio seems to favor anatase formation, and higher equivalence ratio seems to favor srilankite formation, with other parameters fixed.The rare srilankite phase of TiO2 is created in this work using ethylene as both fuel and precursor dopant in the burning premixture. TiO2 nanoparticles (i.e., 5–10 nm) of polymorphs of srilankite TiO2-II, anatase, and rutile are produced by changing residence time and carbon content of the synthesis flow field. By tuning the residence time and fraction of included carbon, different polymorphs are generated. Anatase is formed at 20 torr by a H2/O2/N2 premixed flame, while rutile and srilankite are formed at 20 torr in a H2/C2H4/O2/N2 flame. Longer particle residence time facilitates srilankite formation over rutile. Additional carbon facilitates the formation of srilankite over that of anatase, as evidenced by the greater weight percentage of carbon in the srilankite samples than that in the anatase samples. To rule out the temperature effect on phase formation, srilankite is also synthesized in an ethylene-based flame at a lower characteristic temperature that matches that of an anatase-synthesizing ethylene-free flame. Decomposition of feed ethylene allows a higher percentage of carbon to be doped into the TiO2 lattice, which is the key (along with small nanoparticle size with high internal pressures) in stabilizing the high-pressure metastable srilankite phase in our low-pressure system.
Computational simulation, using the Sandia SPIN code for the flow field and flame structure, a code for particle trajectory, and monodisperse and sectional models for particle growth dynamics, determines final properties, including primary and aggregate particle size, to compare with experiments. Characteristic particle residence times are estimated to be from 4.42 to 15.7 ms. Using pseudo-Voigt fitting on XRD and SAED spectra, nanopowders produced are determined to have anatase percentages varying from 0 to 90%, rutile percentages from 7 to 100%, and srilankite percentages from 0 to 83%. Pseudo-Monte-Carlo method is employed to account for change of direction between “rate of change” of input to output parameters.
Using statistical analysis, the significant contributors to phase changes are narrowed down to equivalence ratio, pressure, residence time, and temperature. By establishing case to case Δ as 0.3 equivalence ratio, 20 torr pressure, 1 ms residence time, and 75K temperature, the pseudo-Monte-Carlo output is analyzed to yield the following conclusions:
-Equivalence ratio exerts large influence on specific phase formation with -37.92 anatase, 16.69 srilankite, and 12.27 %rutile/ Φ case Δ.
-Pressure exerts medium influence on specific phase formation with 19.83 rutile, 15.06 srilankite, and 7.37% %anatase/P case Δ.
-Residence time exerts small influence on specific phase formation with 5.85 srilankite, -5.19 rutile, and -1.45 anatase%/t case Δ.
-Temperature exerts small influence on specific phase formation with 5.49 srilankite, -3.18 rutile, and -2.04 anatase%/T case Δ.
These results are consistent to that observed in the experiments, along with the reasons for the formation of specific phases.Ph.D.Includes bibliographical reference
Implementasi Monitoring Jaringan Berbasis Web Terintegrasi Cacti Menggunakan Notifikasi Telegram
Get PDFImproving the quality of services on the network must be implemented and run easily in every institution, school, home, or other place that uses a computer network as an important means. One appropriate way is to find out network disruptions that occur in a fast time period, so that the interference can be overcome without needing a long time. Knowing the disruption that occurs in a faster time period is not easy if done the old way, that is network users realize that the network is not connected and report it to the network technician. After receiving the report the damaged network will be repaired. With a web-based system that is integrated with cacti, it can monitor and provide information via telegram messages in real time. The technician will immediately fix the disruption that occurred before the report from the user, so that network disruptions that occur will not last long. Keywords : cacti, web, telegram, networkin
Revisión bibliométrica del tratamiento de las aguas residuales mediante residuos frutales como medio de adsorción de colorantes: una visión global
No full textCurrently, conservation of water resources is a major challenge. For this reason, research has intensified into methodologies that are not only efficient but also economically viable for treating wastewater from the textile industry. The objective of this study was to reveal the current state of scientific literature related to the use of fruit waste as a means of adsorbing dyes in wastewater treatment. The methodology used consisted of a bibliometric analysis based on documents indexed in Scopus® published between 2010 and 2022. Significant trends within the field were determined using networks through VOSviewer software. Initially, 705 documents were found and after applying the filters, 532 documents published during the search period were obtained. The study found that China is the leading country, accounting for 38.72 % of all publications. Likewise, author Liu, Y. obtained the highest number of citations, followed by Ren, S. and Yan, Q. In addition, the average number of citations per document was 28.83, with a total of 2027 authors and an average of 3.81 authors per publication. On the other hand, Chemosphere was the journal with the highest number of publications, followed by the Journal of Environmental Chemical Engineering and Water Science & Technology. The results provided a broad overview of the research landscape on wastewater treatment using fruit waste as bioadsorbents, which serves as a basis for future research. Finally, it is concluded that the data obtained provide guidance on the most important authors, journals, materials, mathematical models, and use of characterization techniques. Despite being a relevant topic, a search of the literature reveals no bibliometric analyses on the subject. Thus, bibliometric analyses are an interesting alternative to traditional literature reviews.En la actualidad, la conservación de los recursos hídricos es un desafío importante. Por tal motivo, se ha intensificado el estudio de metodologías que no solo sean eficientes, sino que también sean económicamente viables para tratar aguas residuales de la industria textil. Este estudio tuvo como objetivo revelar el estado actual de la literatura científica relacionada con la utilización de los residuos frutales como medio de adsorción de colorantes en el tratamiento de las aguas residuales. La metodología empleada consistió en un análisis bibliométrico con base en los documentos indexados en Scopus® y publicados entre 2010 y 2022. Las tendencias trascendentales dentro del campo se determinaron utilizando redes por medio del software VOSviewer. Inicialmente, se encontraron 705 documentos y luego de aplicar los filtros se obtuvieron 532 documentos publicados durante el rango de búsqueda. Se encontró que China es el país predominante con el 38,72 % del total de las publicaciones. Asimismo, el autor Liu, Y. obtuvo el mayor número de citaciones seguido por Ren, S. y Yan, Q. Además, el promedio de citas por documento fue de 28,83, con un total de 2027 autores y una media de 3,81 autores por publicación. Por otro lado, Chemosphere fue la revista con mayor número de publicaciones seguidas de Journal of Environmental Chemical Engineering y Water Science & Technology. Los resultados permitieron obtener una visión amplia sobre el panorama investigativo del tratamiento de agua residuales utilizando residuos frutales como bioadsorbentes, lo cual sirve de base para futuras investigaciones. Finalmente, se concluye que los datos obtenidos orientan en cuanto autores, revistas, materiales, modelos matemáticos y uso de técnicas de caracterización más importantes. A pesar de ser un tema relevante, haciendo una búsqueda en la literatura, no se encontraron análisis bibliométricos sobre la temática. Es así como los análisis bibliométricos son una alternativa interesante a las revisiones literarias tradicionales
Revisión bibliométrica del tratamiento de las aguas residuales mediante residuos frutales como medio de adsorción de colorantes: una visión global
Get PDFCurrently, conservation of water resources is a major challenge. For this reason, research has intensified into methodologies that are not only efficient but also economically viable for treating wastewater from the textile industry. The objective of this study was to reveal the current state of scientific literature related to the use of fruit waste as a means of adsorbing dyes in wastewater treatment. The methodology used consisted of a bibliometric analysis based on documents indexed in Scopus® published between 2010 and 2022. Significant trends within the field were determined using networks through VOSviewer software. Initially, 705 documents were found and after applying the filters, 532 documents published during the search period were obtained. The study found that China is the leading country, accounting for 38.72 % of all publications. Likewise, author Liu, Y. obtained the highest number of citations, followed by Ren, S. and Yan, Q. In addition, the average number of citations per document was 28.83, with a total of 2027 authors and an average of 3.81 authors per publication. On the other hand, Chemosphere was the journal with the highest number of publications, followed by the Journal of Environmental Chemical Engineering and Water Science & Technology. The results provided a broad overview of the research landscape on wastewater treatment using fruit waste as bioadsorbents, which serves as a basis for future research. Finally, it is concluded that the data obtained provide guidance on the most important authors, journals, materials, mathematical models, and use of characterization techniques. Despite being a relevant topic, a search of the literature reveals no bibliometric analyses on the subject. Thus, bibliometric analyses are an interesting alternative to traditional literature reviews.En la actualidad, la conservación de los recursos hídricos es un desafío importante. Por tal motivo, se ha intensificado el estudio de metodologías que no solo sean eficientes, sino que también sean económicamente viables para tratar aguas residuales de la industria textil. Este estudio tuvo como objetivo revelar el estado actual de la literatura científica relacionada con la utilización de los residuos frutales como medio de adsorción de colorantes en el tratamiento de las aguas residuales. La metodología empleada consistió en un análisis bibliométrico con base en los documentos indexados en Scopus® y publicados entre 2010 y 2022. Las tendencias trascendentales dentro del campo se determinaron utilizando redes por medio del software VOSviewer. Inicialmente, se encontraron 705 documentos y luego de aplicar los filtros se obtuvieron 532 documentos publicados durante el rango de búsqueda. Se encontró que China es el país predominante con el 38,72 % del total de las publicaciones. Asimismo, el autor Liu, Y. obtuvo el mayor número de citaciones seguido por Ren, S. y Yan, Q. Además, el promedio de citas por documento fue de 28,83, con un total de 2027 autores y una media de 3,81 autores por publicación. Por otro lado, Chemosphere fue la revista con mayor número de publicaciones seguidas de Journal of Environmental Chemical Engineering y Water Science & Technology. Los resultados permitieron obtener una visión amplia sobre el panorama investigativo del tratamiento de agua residuales utilizando residuos frutales como bioadsorbentes, lo cual sirve de base para futuras investigaciones. Finalmente, se concluye que los datos obtenidos orientan en cuanto autores, revistas, materiales, modelos matemáticos y uso de técnicas de caracterización más importantes. A pesar de ser un tema relevante, haciendo una búsqueda en la literatura, no se encontraron análisis bibliométricos sobre la temática. Es así como los análisis bibliométricos son una alternativa interesante a las revisiones literarias tradicionales
