446494 research outputs found
Sort by
A Pythagorean Fuzzy Cognitive Mapping Approach for Iran’s Electricity Sustainability as a Case Study for Developing Economies
No full textTransition to renewable electricity faces diverse challenges, the systemic interdependencies of which are still underexplored. This study applies a Pythagorean Fuzzy Cognitive Map (PFCM) to analyze and prioritize challenges of transitioning to the electricity sustainability across five dimensions of economic, technological, policy, social, and geopolitical. The analysis is based on experts’ opinions from Iran’s energy domain. Results indicate that geopolitical constraints such as sanctions and water scarcity, and social challenges like public acceptance and skills gaps are more influential than conventional economic and technological challenges. The analysis reveals that sanctions (C51) and water stress (C52) have cascading effects, disrupting financing (C11), technology imports (C21–C22), and governance coherence (C31–C33). Meanwhile, low public trust (C41) and fossil fuel subsidies (C13) emerge as secondary but pivotal bottlenecks. The study shows that economic or infrastructural improvement alone cannot drive transition. Instead, it argues that geopolitical solutions such as sanctions relief and social preparedness are prerequisites for starting progress in other domains. These findings suggest that policymakers should prioritize diplomatic engagement and social-centric energy campaigns alongside technical investments
A review of training approaches for floor gymnastics performance
No full textThis study is a systematic literature review aimed at evaluating ten evidence-based training approaches used to enhance floor gymnastics performance. The review includes ten verified scientific articles published between 2013 and 2025, covering core strength development, neuromuscular training, flexibility enhancement, rhythm coordination through music, nutritional strategies, and audiovisual learning tools. The findings indicate that multidimensional training approaches significantly improve technical, physical, and artistic aspects of floor routines. The review highlights the importance of structured, progressive, and evidence-based training to support athlete performance and safety
Dynamics of local leadership and community asset mobilization in Makassar's community-based waste management program
No full textThe waste volume in Makassar City has escalated significantly, reaching over 1,500 tons per day due to changing consumption patterns. Amidst this crisis, community-based waste management programs are a vital solution, though their success is highly dependent on internal dynamics. This phenomenological study analyzes the central role of local leadership and the process of community asset mobilization in sustaining the program's continuity. Data were collected through in-depth interviews and observation, and thematically analyzed to uncover the meaning of the actors' experiences. Findings reveal that local leadership acts as a dynamic catalyst. Leaders mobilize assets by building strategic partnerships with various parties, including the government, CBOs, and the private sector. This collaboration is then operationalized through a structured division of roles and capacity-building programs, such as entrepreneurship and organizational development training, to ensure long-term sustainability. The study concludes that the core of the program's success lies in the leadership's ability to synergistically orchestrate internal and external assets, transforming them into an organized collective movement. Therefore, it is recommended that future support prioritizes strengthening leadership and community organizational capacity, rather than merely physical aid
The dynamically hazardous asteroid 2025 TV
No full textContext. Twenty co-orbital asteroids of Venus are currently known, several of which may evolve into potentially hazardous asteroids (PHAs) over timescales of thousands of years.
Aims. We report the identification and first dynamical characterization of 2025 TV10, a newly discovered Venus co-orbital asteroid, and assess its potential collisional hazard to Earth.
Methods. We performed numerical simulations of a large number of asteroid clones, and we studied their close encounters with Venus and Earth.
Results. The asteroid may leave its co-orbital configuration on timescales of 1200 yr. The orbit of 2025 TV10 is one of the closest of the absolute minimum of the “minimum orbital intersection distance” (MOID) with Earth for the Venus co-orbital asteroids known to date.
Conclusions. Owing to its orbital parameters, 2025 TV10 represents one of the most dynamically hazardous members of the Venus co-orbital population identified to date. Its faint magnitude and restricted observability windows make future observations challenging but essential for constraining its orbit
Innovative Flotation Reagents: Locked Cycle Flotation Testing by Florrea Specialty Reagents for the Challenging Gold Ores in Sarawak
No full textRefractory gold ores, particularly those containing sulfide, pose significant challenges. Flotation is a promising alternative to enhance the recovery of gold from these types of ore. This study investigates gold ore samples from Sarawak, Malaysia. The primary objectives were to assess the concentrate recovery and grade, and identify the effect of the recycle stream through a locked-cycle flotation test. It optimized the flotation process to enhance gold grade and recovery. The flotation process was carried out using mechanical flotation cells, along with generic and Florrea reagents, which included depressants (CMC, Florrea D140- 7), activators (CuSO4, Florrea 621), collectors (PAX, Florrea X2), and frothers (MIBC, Florrea 530X). The flotation products were analyzed for Au, SxS, Fe, and Sb content using fire assay and atomic absorption spectroscopy (AAS) methods. Results from the Locked Cycle Test indicated that utilizing the Florrea Baseline yielded the best Au/S recovery, with +28.50% for Au and +18.66% for S, resulting in concentrate grades of 56.65 ppm Au and 37.35% S
Dissolution and Kinetic Study of Lithium Leaching from β-Spodumene Waste Using Citric Acid
No full textLithium extraction methods from spodumene include beneficiation to produce a concentrate, which requires structural conversion. This process mainly includes the sulfuric acid method, the sulfate roasting method, the alkali method, and the chlorination roasting method. Although sulfuric acid-based processes are industrially mature, producing one ton of lithium carbonate by this method generates 8 – 10 tons of solid waste residue. Based on the chemical assay, the solid waste residue still contains 0.3% of Li. This study will investigate a green process for lithium recovery from waste spodumene processing using citric acid. This study investigates the effect of various leaching variables, including temperature, time, acid concentration, and solid-to-liquid ratio, on lithium extraction efficiency. Raw material characterisation has been conducted using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM) on representative powdered bulk samples. The leach solution has been analysed via ICP-OES to determine elemental composition and calculate recovery rates. After 24 hours of leaching using 1 M citric acid, 10% solid-liquid ratio, and a 60 °C leaching temperature, lithium recovery is at the highest level, at up to 65.7%. Moreover, the kinetics of lithium leaching were studied to determine the controlling mechanism using the shrinking core model. The obtained value of Ea was 52.77 kJ/mol
Existence of solutions and selection problem for quasi-stationary contact mean field games
No full textFirst, we study the existence of solutions for a class of first order mean field games systems
\begin{equation*}
\left\{\begin{aligned}
&H(x,u,Du)=F(x,m(t)),\quad &&x\in M,\ \forall\ t\in[0,T],\\
&\partial_t m-\text{div}\left(m\dfrac{\partial H}{\partial p}(x,u,Du)\right)=0,\quad &&(x,t)\in M\times(0,T],\\
&m(0)=m_0,
\end{aligned}\right.
\end{equation*}
where the system comprises a stationary Hamilton-Jacobi equation in the contact case and an evolutionary continuity equation.
Then, for any fixed , let be a solution of the system
\begin{equation*}
\left\{
\begin{aligned}
&H(x,\lambda u^\lambda,Du^\lambda)=F(x,m^\lambda(t))+c(m^\lambda(t)),\quad &&x\in M,\ \forall t\in[0,T],\\
&\partial_t m^\lambda-\text{div}\left(m^\lambda\dfrac{\partial H}{\partial p}(x,\lambda u^\lambda,Du^\lambda)\right)=0,\quad &&(x,t)\in M\times(0,T],\\
&m(0)=m_0,
\end{aligned}\right.
\end{equation*}
where is the Ma\~n\'e critical value of the Hamiltonian . We investigate the selection problem for the limit of as tends to 0
Purification of Waste Carbon for Battery Applications via Ascorbic Acid Leaching
No full textGraphite is increasingly recognized as a critical material with its essential role in clean energy technologies, specifically as an anode material in lithium-ion batteries (LIBs). With the growing global demand for electric vehicles (EVs) and supply risks, finding alternative sources has become necessary. Waste carbon (WC) materials, which have significant graphite content, offer a promising secondary source for battery applications. Despite developments in recycling technologies, most efforts remain focused on cathode materials from spent LIBs and rely on corrosive leaching agents that are challenging to manage and impact the environment through emissions. Thus, it is essential to advance research focused on waste carbon recycling, and this study seeks to develop a green leaching technology using ascorbic acid to purify waste carbon, particularly graphitic waste from the Acheson furnace, with about 99.85% purity. The effectiveness of ascorbic acid has been investigated for removing impurities like Fe, Al, Ca, and S. A 2-level factorial design was employed using Stat-Ease Design Expert (DOE) software to identify the significant factors and interactions between selected variables such as acid concentration, temperature, and time. The effective removal of Fe, Al, Ca, and S using ascorbic acid leaching demonstrated the potential to enhance the graphite purity to >99.95%, meeting the minimum purity required for battery-grade applications
Effects of Harvest Age and Nitrogen Fertilization Levels on Nutrient Composition and Yield of Red Elephant Grass (
No full textThis study evaluated the effect of harvest age and fertilisation rate on nutrient production of Red Napier Grass (Pennisetum purpureum cv. Red) (RNG) in the fifth harvest period. The design used was a factorial completely randomised design (CRD), with two factors, namely harvest age (50, 60, 70, and 80 days) and fertilization level (P0: 0 kg N/ha/year, P1: 150 kg N/ha/year, and P2: 300 kg N/ha/year). Each treatment combination was repeated three times, resulting in 12 treatments. Parameters observed included nutrient content i.e. Dry Matter (DM), Organic Matter (OM), Crude Protein (CP), Crude Fiber (CF), Crude Fat and nutrient production of DM, OM and CP. The results showed that harvesting age and fertilization rate had a significant effect on nutrient content. The interaction between harvest age and fertilizer level also had a very significant effect on nutrient content. The results also showed that harvest age and fertilizer level had a significant effect (P0.05). The highest DM and OM production was found in the P2 treatment at the age of 80 days, while CP production reached its peak at the age of 60 days with the same fertilizer level. It is recommended to harvest Red Napier Grass at the age of 80 days with fertilizer treatment P2 (300 kg N/ha/year) to get optimal yields. In addition, the CP content that decreases at older harvest ages can be added with concentrate feed in animal
The Influence Environmental Dimension of Good Dairy Farming Practices on Sustainability Smallholder Farm-Income at Malang Raya, East Java, Indonesia
No full textSmallholder dairy farmer faced many challenges, including fluctuating milk process, rising input cost, and pressure to comply with quality and adopting environmental requirements. Implementing good dairy farming practice (GDFP) particularly in the environment dimension offered most useful in improving efficiency, productivity, and milk quality, hence generating farm income. This study investigates the adoption of environment dimension of GDFP in Jabung sub-district, Malang Raya, East Java Province of Indonesia. The 76 respondents who members of the "KUBE PSP Maju Mapan group were selected by multistage sampling method. They were grouped into two farm-scale based on Animal Unit (AU): farm-scale I (having 1- 6.38 AU; n=46 farmers) and farm-scale II (having 6.39 - 13.75 AU; n=30 farmers). Survey method was applied to gather primary data, whereas secondary data was provided by the related institutions. Descriptive and regression analyses have been carried to analyse the data. Results found that environmental practices vary in the two farm-scales. For farm-scale I, forage planting decrease farm income, while and housing density enhanced the farm return. For farm-scale II, cleaner housing improved farm income, whereas waste treatment activities and heavy water use reduce profitability due to additional operational costs. The study highlights the need future investigation that targeted policy interventions, cooperative-level infrastructure, and more nuanced sustainability strategies that support both environmental sustainability and rural livelihoods