The growing demand for low-cost, sustainable conductive filaments for additive manufacturing motivates the exploration of recycled polymer feedstocks as alternatives to virgin materials. However, the effects of prior thermal reprocessing on both the electrical performance and morphological integrity of recycled PLA (rPLA)–carbon black (CB) composite filaments remain insufficiently characterised, particularly under single-screw extrusion conditions. This study fabricates and characterises conductive filaments from virgin PLA and rPLA, each loaded with CB at 0.2, 0.6, and 1.0 wt%, using a low-cost desktop single-screw extruder. Melt blending was found to be essential for achieving continuous filament extrusion, as ball milling produced insufficient filler dispersion and frequent nozzle jamming. Electrical conductivity increased markedly with CB content, with both systems approaching percolation onset at 1.0 wt%, where conductivity reached 0.369 mS/m for PLA-CB and 0.362 mS/m for rPLA-CB. SEM and EDX analyses revealed that rPLA exhibited incomplete cross-sectional filling and a higher surface O/C ratio, both consistent with chain-scission-induced molecular degradation while quantitative agglomerate size analysis showed rPLA-CB produced larger and more heterogeneously distributed CB clusters compared to PLA-CB. Despite these microstructural differences, rPLA-CB achieved comparable electrical performance to its virgin counterpart, demonstrating its viability as a sustainable feedstock for semiconductive and antistatic additive manufacturing applications.
In plastic injection molding, minimizing defects is crucial for sustainable and stable manufacturing because resin behavior and molding conditions fluctuate due to variations in material lots, seasonal shifts, and factory environmental factors such as temperature and humidity. Among various process parameters, mold temperature - specifically the mold mating surface temperature immediately after part ejection- plays a critical role in mitigating these variations and maintaining consistent product quality. However, embedding conventional sensors into the mating surface is structurally difficult. While non-contact infrared thermography is an effective alternative, shiny metallic mold surfaces suffer from low emissivity, leading to inaccurate readings. Furthermore, high-end thermal cameras are often cost-prohibitive for small and medium-sized enterprises (SMEs). To address these challenges, this study proposes a low-cost remote temperature monitoring system. Small counterbores were machined outside the mold cavity and coated with a high-emissivity black body paint, resolving the emissivity problem without affecting product quality. Molding experiments were conducted by intentionally inducing short-shot defects using resins with different flow properties to simulate process variations. The temperature variations were captured using both high-end and low-cost infrared thermometers, and analyzed using the Mahalanobis distance (MD value). The results demonstrated that the proposed system could successfully detect short shots on a cycle-by-cycle basis. Notably, the low-cost thermometer provided adequate monitoring accuracy when measured from the front, comparable to the high-end camera. This system offers a cost-effective, easily implementable solution for remote process monitoring, significantly contributing to the digital transformation (DX) and smart factory realization in SMEs.
Rice production in South and Southeast Asia faces serious challenges, including acute labor shortages and rising wages, which threaten regional food security. Mechanical rice transplanting offers a promising solution; however, evidence on labor savings, especially region-specific data, remains inconsistent. This systematic review and meta-analysis aimed to quantify labor savings from mechanical versus manual transplanting across Bangladesh, India, Nepal, and the Philippines. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic search was conducted across four major scientific databases (2000–2026) using Boolean search terms for mechanical transplanting and labor outcomes. Of 284 initial records, 52 met eligibility criteria, and 40 provided sufficient data for a random-effects meta-analysis. The Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) risk-of-bias tool and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach were used for bias assessment and evidence-certainty evaluation, respectively. Results showed that mechanical transplanting reduced labor needs by 30–94% compared with manual methods. The pooled mean difference was −17.2 man-days·ha−1 (95% CI: −20.1 to −14.3; I2 = 68%; p < 0.001), with GRADE certainty rated as moderate. In conclusion, mechanical rice transplanting consistently reduced labor requirements across all four countries, with additional yield benefits, though adoption remained constrained by high capital costs and mat-type nursery requirements. These findings support mechanization as a key strategy to improve labor efficiency and food security in South and Southeast Asian rice systems.
Reliable energy access is widely recognized as essential for agricultural development, yet adoption of off-grid renewable energy technologies (RETs) in the Global South remains uneven despite their high potential. While RETs are increasingly promoted as solutions to food insecurity and energy poverty, evidence on what enables or constrains their uptake across agricultural contexts remains fragmented. This study systematically reviews 18 peer-reviewed articles published between 2013 and 2025 using the PRISMA framework and synthesizes findings through a PESTEL lens. The literature has expanded in recent years, reflecting growing policy attention to the energy–agriculture nexus, but remains concentrated in Asia and heavily focused on solar irrigation, with Africa, Latin America, and post-harvest applications largely underrepresented. Across studies, the most prominent drivers of adoption are technology reliability and support (n=18), sustainable resource use (n=18), and economic empowerment (n=17), while key barriers include technological limitations (n=18), high upfront costs (n=16), and climate or resource constraints (n=15). These drivers and barriers interact across political, economic, social, technological, environmental, and legal dimensions, shaping both adoption outcomes and scalability. The findings highlight the need for inclusive financing mechanisms, socially equitable program design, and coherent regulatory frameworks to unlock the potential of off-grid RETs in agriculture, with implications for productivity, poverty reduction, food security, and climate resilience in support of SDGs 1, 2, 7, and 13.
Rapid urbanization in developing countries has intensified housing challenges for younger generations, particularly Zillennials (aged 24–34), who demand affordable, accessible, and sustainable living environments. This study investigates the optimal location for small-scale housing integrated with large-scale developments in the Jakarta Metropolitan Area (JMA), emphasizing mobility as the primary criterion. The research is guided by a conceptual framework that synthesizes compact city principles, the 15-minute city concept, and Zillennial lifestyle preferences, with walkability and bikeability serving as mediating variables. Mobility simulations were conducted using the Urban Modeling Interface (UMI), applying Walk Score parameters to evaluate walking and cycling accessibility. Six simulation scenarios were tested using a case study of small-scale housing integrated with large-scale developments across four distance zones (400 m, 800 m, and up to 5 km). The results demonstrate that walking and cycling mobility are primarily determined by proximity to facilities rather than the diversity of facilities. The simulations confirm that the optimal location for affordable housing integrated with larger developments lies within a 400–800 m range. At this distance, walkability falls into the “Somewhat Walkable” category, while cycling achieves a “Very Bikeable” rating. The findings indicate that proximity enhances mobility. However, extremely close facilities do not necessarily result in higher scores than the 400–800 m threshold. This study concludes that infill housing within 400–800 m radius of large-scale developments offers a practical, affordable, and sustainable solution for Zillennials. It supports compact city strategies, enhances social connectivity, and reduces reliance on motorized transport. Despite limitations related to distance-based simulation and the use of a single case study, the research provides valuable insights for policymakers, developers, and urban planners in designing youth-oriented housing in rapidly urbanizing contexts.
