Luthfi Hakim^1,*, Yunida Syafriani Lubis², Apri Heri Iswanto¹, Harisyah Manurung¹, Jayusman², Widya Fatriasari³, Petar Antov⁴, Tomasz Rogoziński⁵, Lee Seng Hua⁶, Nur Izyan Wan Azelee⁷

Journal of Renewable Materials, Vol.13, No.12, pp. 2355-2373, 2025, DOI:10.32604/jrm.2025.02025-0078 - 23 December 2025

Abstract Activated charcoals were synthesized from sugar palm bunches (SPB) of the native tree of Arenga longipes in Indonesia. The synthesized activated charcoal (AC) was characterized, and utilized as an absorbent for heavy metals (lead/Pb and copper/Cu) through thermal activation. The synthesis of AC was accomplished through furnace activation at temperatures of 500°C, 600°C, 700°C, and 800°C. Acid chlorides were blended with the SPB-AC samples at 5% impregnation level and subsequently subjected to washing for activation, resulting in the elimination of volatile substances and ash content, which facilitates the development of a porous structure in the activated… More >

O. Mekhbi^a, K. Kamli^b,*, Z. Hadef^b, O. Kamli^c, M. Bouatrous^d, N. Houaidji^e, L. Zighed^h

Chalcogenide Letters, Vol.22, No.4, pp. 331-339, 2025, DOI:10.15251/CL.2025.224.331

Abstract This work presents a hybrid study that employs Ultrasonic Spray method for the deposition of SnS absorber films and SCAPS-1D simulation method for the analysis of various solar cell topologies. Different deposition times have been employed to optimize structural, optics, and electrical properties. To evaluate their potential as absorber layers for solar cells, the films were analyzed by using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and tested for electrical performance. Complementary numerical simulations were carried out with SCAPS-1D in modeling ZnO:Al/i-ZnO/SnS₂/SnS solar cell structures. Results showed that optimized SnS thickness of 2.5 µm and high carrier More >

B. Yassine, B. Tahar^*, G. Fathi, B. Meriem, B. Ibtissem

Chalcogenide Letters, Vol.22, No.7, pp. 637-648, 2025, DOI:10.15251/CL.2025.227.637 - 17 December 2025

Abstract In this paper, we designed a two-junction (tandem) solar cell model (tandem solar cell), consisting of an top and bottom subcell with absorber layers of Cu₂SnZnS₄ (CZTS) and Cu₂SnZnSe₄ (CZTSe) materials, respectively, for each subcell with a ZnS buffer layer and a ZnO window layer. This model was validated using the SCAPS-1D numerical simulation program. We also optimized the performance of the tandem cell as a whole using the simulation by studying the effect of the thickness of the absorber layer of the top subcell and the thickness of the absorber layer of the bottom subcell More >

Y. B. K. Kumar^a,, S. G. Prasad^b, A. S. S. Smitha^c, S. M. Naidu^d, G. S. Babu^c, P. U. Bhaskar^e, U. Chalapathi^f,

Chalcogenide Letters, Vol.22, No.9, pp. 847-854, 2025, DOI:10.15251/CL.2025.229.847

Abstract Cu₂MgSnS₄ thin films have emerged as potential candidates for use in photovoltaic applications owing to their direct band gap properties. These quaternary compounds are fabricated through the spray pyrolysis method at 175 °C, utilizing two different carrier gases, such as air and nitrogen. After pyrolysis, deposited films are annealed at 450 °C for 1 hour. Structural analysis confirms the films exhibit a tetragonal kesterite structure. Using nitrogen as the carrier gas results in a larger crystallite size, accompanied by a reduction in both the dislocation density and microstrain. Raman spectroscopy further validates phase purity. Surface morphology analysis indicates More >

Fan He^1,2,3,*, Xu He⁴, Jie Wang¹, Yu Hu⁵

Chalcogenide Letters, Vol.22, No.11, pp. 939-949, 2025, DOI:10.15251/CL.2025.2211.939

Abstract Selenium (Se) has garnered significant attention as a promising wide-bandgap material for photovoltaic applications. However, progress in enhancing the efficiency of Se solar cells remains limited. This study addresses this challenge by targeting the critical emitter/Se absorber interface for performance improvement. Through numerical simulations, we systematically investigate the impact of key interface properties—specifically, band alignment and defect characteristics—on device performance. Our results demonstrate that a slight positive conduction band offset (CBO) effectively strengthens absorber band bending and reduces hole concentration at the Se surface. Furthermore, minimizing interface defect density or incorporating donor-type defects significantly alleviates More >

S. Srinivasa senthil, K. Vijayakumar^*

Energy Engineering, Vol.122, No.12, pp. 5149-5173, 2025, DOI:10.32604/ee.2025.070889 - 27 November 2025

Abstract Heating, ventilation, and air conditioning (HVAC) systems contribute substantially to global energy consumption, while rejecting significant amounts of low-grade heat into the environment. This paper presents a non-intrusive spiral-coil heat exchanger designed to recover waste heat from the outdoor condenser of a split-type air conditioner. The system operates externally without altering the existing HVAC configuration, thereby rendering it suitable for retrofitting. Water was circulated as the working fluid at flow rates of 0.028–0.052 kg/s to assess thermal performance. Performance indicators, including the outlet water temperature, heat transfer rate, convective coefficient, and efficiency, were systematically evaluated.… More >

Lailan Ni`mah^1,*, Sri Rachmania Juliastuti², Mahfud Mahfud²

Journal of Renewable Materials, Vol.13, No.11, pp. 2169-2190, 2025, DOI:10.32604/jrm.2025.02025-0044 - 24 November 2025

Abstract This study evaluates the effectiveness of microwave technology in producing activated carbon from lemongrass waste, an underutilized agricultural byproduct. Microwave-assisted production offers faster heating, lower energy consumption, and better process control compared to conventional methods. It also enhances pore development, resulting in larger, cleaner, and more uniform pores, making the activated carbon more effective for adsorption. The microwave-assisted process significantly accelerates production, reducing the required time to just 10 min at a power of 400 W. Activated carbon derived from lemongrass waste at 400 W exhibits a water absorption capacity of 7.88%, ash content of… More > Graphic Abstract

Zhiguang Zhang, Caisheng Wei, Guanhua Huang, Zeyang Yin^*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.33, No.3, pp. 1-1, 2025, DOI:10.32604/icces.2025.010967

Abstract An optimal predictive control method for spacecraft rendezvous based on Koopman operator is proposed for the the libration point rendezvous problem of Earth-moon system. Firstly, the relative motion dynamics model between the chaser and the target spacecraft in the Earth-moon system is established. Secondly, considering the influence of nonlinearity on spacecraft rendezvous control, a global linearization method of nonlinear rendezvous system driven by Koopman operator is proposed. In this method, the Koopman linearization operator is approximated by the extended dynamic mode decomposition (EDMD) method on the finite dimension. Subsequently, based on the linearization model of… More >

Haiyan Yu^1,*, Mingdong Li¹, Ning Guo¹, Fengying Ren¹, Yongheng Lu¹, Mu Du^2,*

Frontiers in Heat and Mass Transfer, Vol.23, No.5, pp. 1495-1509, 2025, DOI:10.32604/fhmt.2025.071263 - 31 October 2025

Abstract High-temperature radiative cooling is essential for solar absorbers, as it mitigates efficiency degradation resulting from thermal accumulation. While porous structures have proven effective in enhancing absorber performance, practical manufacturing processes and prolonged operational wear inevitably introduce surface roughness and structural deviations, which profoundly impact radiative properties. This study constructs a ZnS/Ag solar absorber model with surface roughness and employs the finite-difference time-domain method to investigate how characteristic length, surface roughness, porosity, pore shape factor, and taper influence its radiative properties in the 3 μm–5 μm band at 750 K. Results show optimal absorption at a More >

Anna Elisa Silva, Eduardo Thiago Formigari, João Pedro Mayer Camacho Araújo, Dagoberto de Oliveira Silva, Jürgen Andreaus, Eduardo Guilherme Cividini Neiva^*

Journal of Renewable Materials, Vol.13, No.10, pp. 1899-1912, 2025, DOI:10.32604/jrm.2025.02025-0130 - 22 October 2025

Abstract Here, we report a comprehensive study on the characterization of cotton biomass residue, its conversion into carbon-based materials via pyrolysis, and its application as an electrochemical sensor for ascorbic acid (AA). The compositions, morphologies, and structures of the resulting materials were investigated using XRD, FTIR, TGA, SEM, and EDS. Pyrolysis was carried out in an air atmosphere at different temperatures (300°C and 400°C) and durations (1, 60, and 240 min), leading to the transformation of lignocellulosic cotton residue into carbon-based materials embedded with inorganic nanoparticles, including carbonates, sulfates, chlorates, and phosphates of potassium, calcium, and… More > Graphic Abstract