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Research Article
Green Synthesis, Characterization, and Antimicrobial Activity of ZnO Nanoparticles Using Zanthoxylum gilletii Leaf Extract
Issue:
Volume 11, Issue 3, September 2026
Pages:
92-103
Received:
16 June 2026
Accepted:
26 June 2026
Published:
17 July 2026
Abstract: The green synthesis of zinc oxide (ZnO) nanoparticles has attracted significant attention as an eco-friendly alternative to conventional chemical methods. In this study, ZnO nanoparticles were synthesized using aqueous leaf extract of Zanthoxylum gilletii, where plant phytochemicals acted as reducing and stabilizing agents. Key synthesis parameters, including precursor concentration, reaction pH, and temperature, were systematically optimized to obtain nanoparticles with desirable physicochemical properties. Optimal synthesis conditions were achieved at 0.7 M precursor concentration, pH 10, and 60°C, resulting in well-defined and stable nanoparticles. The synthesized ZnO nanoparticles were characterized using UV–Visible spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and photoluminescence (PL) analysis. UV–Vis results showed a characteristic absorption peak at 356 nm with a band gap of 3.12 eV, confirming ZnO formation. FTIR analysis revealed a Zn–O stretching vibration at ~410 cm-1, while XRD confirmed a hexagonal wurtzite structure with an average crystallite size of 29.70 nm. PL spectra exhibited an emission peak at 401 nm, indicating defect-related optical behaviour. The antimicrobial activity of the synthesized nanoparticles was evaluated against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans using the agar disc diffusion method. The nanoparticles exhibited significant antimicrobial activity, with mean zones of inhibition ranging from 18.67 mm to 22.00 mm. Statistical analysis (one-way ANOVA, p > 0.05) indicated no significant difference among the tested microorganisms, demonstrating consistent broad-spectrum antimicrobial performance. These findings demonstrate that Zanthoxylum gilletii-mediated green synthesis provides an effective and sustainable approach for producing ZnO nanoparticles with controlled structural and optical properties and strong antimicrobial potential.
Abstract: The green synthesis of zinc oxide (ZnO) nanoparticles has attracted significant attention as an eco-friendly alternative to conventional chemical methods. In this study, ZnO nanoparticles were synthesized using aqueous leaf extract of Zanthoxylum gilletii, where plant phytochemicals acted as reducing and stabilizing agents. Key synthesis parameters...
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Research Article
The Effect of Food Quality, Price, and Menu Variety on Consumer Repurchase in Restaurant
Issue:
Volume 11, Issue 3, September 2026
Pages:
104-114
Received:
7 June 2026
Accepted:
27 June 2026
Published:
22 July 2026
Abstract: Repurchase intention is essential for sustaining the competitiveness of hotel restaurants because repeat guests contribute to long-term profitability and customer loyalty. Although previous studies have examined the effects of food quality, price, and menu variety on customer behaviour, limited research has simultaneously investigated their relationships with repurchase intention through the mediating role of guest satisfaction in the context of hotel restaurants. Therefore, this study aims to examine the direct and indirect effects of food quality, price, and menu variety on repurchase intention, with guest satisfaction serving as a mediating variable. A quantitative causal research design was employed using a survey of 220 guests who had dined at Tjokro Restaurant, Grand Tjokro Hotel Yogyakarta. Data were collected through a structured questionnaire and analyzed using Partial Least Squares Structural Equation Modelling (PLS-SEM). The findings reveal that food quality and menu variety have positive and significant effects on both guest satisfaction and repurchase intention. Price has a significant negative effect on guest satisfaction but does not directly influence repurchase intention. Guest satisfaction positively affects repurchase intention and significantly mediates the relationships between food quality, price, menu variety, and repurchase intention. These findings demonstrate that repeat-purchase behaviour in hotel restaurants is driven not only by product-related attributes but also by guests' overall satisfaction with their dining experience. The study contributes to hospitality marketing literature by clarifying the mediating role of guest satisfaction and provides practical guidance for hotel managers in designing effective menu, pricing, and food quality strategies to encourage repeat patronage.
Abstract: Repurchase intention is essential for sustaining the competitiveness of hotel restaurants because repeat guests contribute to long-term profitability and customer loyalty. Although previous studies have examined the effects of food quality, price, and menu variety on customer behaviour, limited research has simultaneously investigated their relatio...
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Research Article
Economic Performance Analysis of Organic Rankine Cycle Retrofit for Carbon Neutral Shipping in the Gulf of Guinea
Victor Effiong Odokowo*
,
Robert Poku,
Oyinkepreye Lucky Bebeteidoh,
Ezenwa Alfred Ogbonnaya
Issue:
Volume 11, Issue 3, September 2026
Pages:
115-129
Received:
10 June 2026
Accepted:
8 July 2026
Published:
28 July 2026
DOI:
10.11648/j.ajset.20261103.13
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Views:
Abstract: This study presents a detailed economic assessment tailored for retrofitting marine diesel engine (MDE) with Organic Rankine Cycle (ORC) towards attaining energy efficiency and carbon neutrality in shipping. Addressing a vital gap in current research, the study, adeptly synchronizes thermodynamics, mass and energy balance equations coupled with economic indices to assess the viability of ORC retrofit technology onboard a tanker vessel on voyage in the Gulf of Guinea (GoG). To define a roadmap to the adoption of ORC onboard towards economic, energy and emission efficiency, the simulation and analysis were brought to fruition applying MATLAB. The results obtained establish that employing ORC retrofit significantly boosts the overall ship operational and economic performances by converting Waste Heat (WH) into power. Results showed that ORC retrofit remains attractive in the case study ship, with a Capital Expenditure (CAPEX) range of 20 to 60%, providing a lower Levelized Cost of Electricity (LCOE) and maximum Net Present Value (NPV). An interest rate of less than 8 % produces a strongly positive NPV and a LCOE of ₦80 per kWh. A rise in fuel price to about 0.9% cost/kg has a positive effect on the IRR and a reduction in the DPBT below 4 years. Analysis revealed that below 60% of base running hours, the NPV may turn negative causing the ORC retrofit investment unbeneficial and unviable. Above 60% of base running hours, the NPV rises, signaling the ranges of viability of the ORC retrofit especially in the GOG. The study also highlights the importance of adopting a well-matched ORC unit based on a vessel’s peculiarity of WH. Also, a proper blend of economic indicators is imperative to achieve an economically viable retrofitted system for enhanced operational and energy efficiency for a carbon neutral shipping.
Abstract: This study presents a detailed economic assessment tailored for retrofitting marine diesel engine (MDE) with Organic Rankine Cycle (ORC) towards attaining energy efficiency and carbon neutrality in shipping. Addressing a vital gap in current research, the study, adeptly synchronizes thermodynamics, mass and energy balance equations coupled with eco...
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