14 research outputs found
Statistical optimisation of process parameters on the efficiency of N-TiO2 dye sensitised solar cell using response surface methodology (RSM)
No full textPhase Transformation and Band Gap Narrowing in Mechanochemically Synthesized Nitrogen-Doped TiO₂ for use in Dye Sensitized Solar Cell
No full textTitanium dioxide (TiO₂) is widely used as a photoanode in dye-sensitized solar cells (DSSCs), but its wide band gap (3.0–3.2 eV) restricts absorption to the ultraviolet region, limiting solar energy conversion efficiency. Nitrogen doping has been recognized as an effective strategy to extend the optical response of TiO₂ into the visible spectrum and improve charge separation. In this study, nitrogen-doped TiO₂ (N-TiO₂) nanocrystals were synthesized via a mechanochemical method using high-energy ball milling of commercial TiO₂ (P25) in ammonium hydroxide solution. Structural and surface analyses were carried out using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). XRD results revealed that the synthesized samples consisted mainly of anatase and rutile phases, with mechanical energy promoting a partial transformation of brookite to rutile. XPS confirmed the incorporation of nitrogen into the TiO₂ lattice, showing distinct Ti–N and Ti–O–N bonding states. The incorporation of nitrogen decreased the band gap and expanded the spectral response of TiO₂ into the visible-light region, while also enhancing oxygen adsorption and reducing charge recombination. These modifications are expected to improve the photocurrent density and overall photovoltaic performance of N-TiO₂ based DSSCs. The findings highlight mechanochemical synthesis as a simple and effective route for producing visible-light-active N-TiO₂ nanomaterials for next-generation solar energy applications
Electrical properties of graphene film for counter electrode in dye sensitized solar cells
No full textWavelet Attention VGG19 and XGBOOST for Classification of Skin Disease
No full text<p><strong>Abstract:</strong> This research paper introduces a novel framework for skin disease classification, combining Wavelet Attention VGG19 and XGBoost algorithms. Wavelet Attention VGG19 leverages the power of deep learning and wavelet attention mechanisms to extract discriminative features from skin lesion images, while XGBoost, a gradient boosting technique, complements the feature extraction capabilities with its ability to handle complex data relationships. The integration of these methodologies aims to improve accuracy and resilience in binary skin disease classification. The two goals of this study are to first improve feature learning and representation from skin lesion images by introducing wavelet attention into the VGG19 architecture, and second to improve classification performance by utilising XGBoost's ensemble and generalisation capabilities.</p>
<p><strong>Keywords:</strong> Wavelet Attention, Xgboost, deep learning, convolutional neural network, skin disease classification, VGG19.</p>
<p><strong>Title:</strong> Wavelet Attention VGG19 and XGBOOST for Classification of Skin Disease</p>
<p><strong>Author:</strong> Samaila Audu, Ali Ahmad Aminu</p>
<p><strong>International Journal of Computer Science and Information Technology Research</strong></p>
<p><strong>ISSN 2348-1196 (print), ISSN 2348-120X (online)</strong></p>
<p><strong>Vol. 11, Issue 4, October 2023 - December 2023</strong></p>
<p><strong>Page No: 5-13</strong></p>
<p><strong>Research Publish Journals</strong></p>
<p><strong>Website: www.researchpublish.com</strong></p>
<p><strong>Published Date: 07-October-2023</strong></p>
<p><strong>DOI: <a href="https://doi.org/10.5281/zenodo.8416714">https://doi.org/10.5281/zenodo.8416714</a></strong></p>
<p><strong>Paper Download Link (Source)</strong></p>
<p><strong><a href="https://www.researchpublish.com/papers/wavelet-attention-vgg19-and-xgboost-for-classification-of-skin-disease">https://www.researchpublish.com/papers/wavelet-attention-vgg19-and-xgboost-for-classification-of-skin-disease</a></strong></p>International Journal of Computer Science and Information Technology Research, ISSN 2348-1196 (print), ISSN 2348-120X (online), Research Publish Journals, Website: www.researchpublish.co
Chloroplast genome of Ecbolium viride: Plastome evolution and Phylogenomics of Justiceae (Acanthaceae, Acanthoideae)
No full textJusticieae is the most taxonomically complex tribe in Acanthaceae. Here, we sequenced the plastome of Ecbolium viride, a medicinally important species. The genome was analyzed with previously reported plastome of Justiceae. The plastome of E. viride has quadripartite structure with a length of 151, 185 bp. The comparative genomic analyses revealed no structural inversion in Justiceae and some regions (rpoC2, ycf2, ycf1 and ndhH rps16-trnQ-UGG, and trnL-CAA-ycf15) exhibiting a significant level of nucleotide divergence. The positive selection analyses revealed that some species in the tribe have undergone adaptive evolution. The visualization of the boundaries between the single copy and inverted repeat regions revealed that Justiceae chloroplast genome experienced some levels of variation which give an insight into the evolution of the species. The longest genome was in the earliest diverged taxa of the tribe P. haikangense and from this genome, a series of contraction and expansion occurred contributing to the evolution of other lineages. The plastome-based phylogeny revealed and confirmed the monophyly of Justiceae, polyphyly of Justicia and supported the tribal classification Graptophyllinae, Tetrameriinae, Isoglossinae. We proposed that Declipterinae should be treated as subtribe and the status of Justiciinae can only be confirmed after the resolution of the polyphyletic JusticiaThe presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Response surface modeling of photogenerated charge collection of silver-based plasmonic dye-sensitized solar cell using central composite design experiments
No full textIn this study, silver nanoparticles (AgNP) have been prepared and successfully incorporated in TiO2 nanopowder and used in dye-sensitized solar cell as photoanode. The effect of the AgNP concentration and photoanode film thickness on the charge collection efficiency of a photogenerated electron at the external circuit was investigated using response surface methodology. A multiple regression analysis of second order polynomial was employed to fit the experimental data and an empirical model was subsequently developed using analysis of variance (ANOVA). The results show that two independent variables (AgNP concentration and photoanode film thickness) have significantly influenced the charge collection efficiency of the silver-based plasmonic DSSC. An optimum charge collection of 64.3% was obtained at AgNP concentration and film thickness of 5%wt and 10 μm, respectively. Keywords: Modeling, Solar cell, Optimization, Plasmoni
Statistical optimisation of process parameters on the efficiency of N-TiO2 dye sensitised solar cell using response surface methodology (RSM)
No full textIn this study, nitrogen doped titanium dioxide-based dye-sensitised solar cell was successfully fabricated using screen printing technique to discover the optimisation of process parameters for the solar cell efficiency using response surface methodology (RSM). Parameter optimisation has been a major concern in solar cell fabrication. The selected parameters were: nitrogen concentration (15-25 mg of urea), the film thickness (25-60 µm) and dye loading time (12-24 hours), the optimum condition which yields the highest efficiency of 3.5% was at 15 mg nitrogen concentration, 25 µm film thickness and 24-hours dye loading time. Film thickness was found to have a significant influence on efficiency while the loading time exceeding 18 hours has the least significant effect
Enhanced visible light absorption and reduced charge recombination in AgNP plasmonic photoelectrochemical cell
No full textIn this research work, silver nanoparticles (AgNP) were synthesized using a simple solvothermal technique, the obtained AgNP were used to prepare a titania/silver (TiO2/Ag) nanocomposites with varied amount of Ag contents and used to fabricated a photoanode of dye-sensitized solar cell (DSSC). X-ray photoelectron spectroscopy (XPS) was used to ascertain the presence of silver in the nanocomposite. A photoluminance (PL) spectra of the nanocomposite powder shows a low PL activity which indicates a reduced election- hole recombination within the material. UV–vis spectra reveal that the Ag in the DSSC photoanode enhances the light absorption of the solar cell device within the visible range between λ = 382 nm and 558 nm nm owing to its surface plasmon resonance effect. Power conversion efficiency was enhanced from 4.40% for the pure TiO2 photoanode based device to 6.56% for the device fabricated with TiO2/Ag due to the improvement of light harvesting caused by the localized surface plasmonic resonance effect of AgNP. The improvement of power conversion was also achieved due to the reduced charge recombination within the photoanode
Enhanced visible light absorption and reduced charge recombination in AgNP plasmonic photoelectrochemical cell
No full textIn this research work, silver nanoparticles (AgNP) were synthesized using a simple solvothermal technique, the obtained AgNP were used to prepare a titania/silver (TiO2/Ag) nanocomposites with varied amount of Ag contents and used to fabricated a photoanode of dye-sensitized solar cell (DSSC). X-ray photoelectron spectroscopy (XPS) was used to ascertain the presence of silver in the nanocomposite. A photoluminance (PL) spectra of the nanocomposite powder shows a low PL activity which indicates a reduced election- hole recombination within the material. UV–vis spectra reveal that the Ag in the DSSC photoanode enhances the light absorption of the solar cell device within the visible range between λ = 382 nm and 558 nm nm owing to its surface plasmon resonance effect. Power conversion efficiency was enhanced from 4.40% for the pure TiO2 photoanode based device to 6.56% for the device fabricated with TiO2/Ag due to the improvement of light harvesting caused by the localized surface plasmonic resonance effect of AgNP. The improvement of power conversion was also achieved due to the reduced charge recombination within the photoanode. Keywords: Nanoparticle, Silver, Plasmonic, Power, Photo
Enhanced visible light absorption and reduced charge recombination in AgNP plasmonic photoelectrochemical cell
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