Hasil untuk "Municipal refuse. Solid wastes"

Rodrigo Batista, Luís Filipe Cunha, Purificação Silvano et al.

Municipal meeting minutes are official documents of local governance, exhibiting heterogeneous formats and writing styles. Effective information retrieval (IR) requires identifying metadata such as meeting number, date, location, participants, and start/end times, elements that are rarely standardized or easy to extract automatically. Existing named entity recognition (NER) models are ill-suited to this task, as they are not adapted to such domain-specific categories. In this paper, we propose a two-stage pipeline for metadata extraction from municipal minutes. First, a question answering (QA) model identifies the opening and closing text segments containing metadata. Transformer-based models (BERTimbau and XLM-RoBERTa with and without a CRF layer) are then applied for fine-grained entity extraction and enhanced through deslexicalization. To evaluate our proposed pipeline, we benchmark both open-weight (Phi) and closed-weight (Gemini) LLMs, assessing predictive performance, inference cost, and carbon footprint. Our results demonstrate strong in-domain performance, better than larger general-purpose LLMs. However, cross-municipality evaluation reveals reduced generalization reflecting the variability and linguistic complexity of municipal records. This work establishes the first benchmark for metadata extraction from municipal meeting minutes, providing a solid foundation for future research in this domain.

Rishab Alagharu, Ishneet Sukhvinder Singh, Shaibi Shamsudeen et al.

Language models are commonly fine-tuned for safety alignment to refuse harmful prompts. One approach fine-tunes them to generate categorical refusal tokens that distinguish different refusal types before responding. In this work, we leverage a version of Llama 3 8B fine-tuned with these categorical refusal tokens to enable inference-time control over fine-grained refusal behavior, improving both safety and reliability. We show that refusal token fine-tuning induces separable, category-aligned directions in the residual stream, which we extract and use to construct categorical steering vectors with a lightweight probe that determines whether to steer toward or away from refusal during inference. In addition, we introduce a learned low-rank combination that mixes these category directions in a whitened, orthonormal steering basis, resulting in a single controllable intervention under activation-space anisotropy, and show that this intervention is transferable across same-architecture model variants without additional training. Across benchmarks, both categorical steering vectors and the low-rank combination consistently reduce over-refusals on benign prompts while increasing refusal rates on harmful prompts, highlighting their utility for multi-category refusal control.

Ricardo Campos, Ana Filipa Pacheco, Ana Luísa Fernandes et al.

City councils play a crucial role in local governance, directly influencing citizens' daily lives through decisions made during municipal meetings. These deliberations are formally documented in meeting minutes, which serve as official records of discussions, decisions, and voting outcomes. Despite their importance, municipal meeting records have received little attention in Information Retrieval (IR) and Natural Language Processing (NLP), largely due to the lack of annotated datasets, which ultimately limit the development of computational models. To address this gap, we introduce CitiLink-Minutes, a multilayer dataset of 120 European Portuguese municipal meeting minutes from six municipalities. Unlike prior annotated datasets of parliamentary or video records, CitiLink-Minutes provides multilayer annotations and structured linkage of official written minutes. The dataset contains over one million tokens, with all personal identifiers de-identified. Each minute was manually annotated by two trained annotators and curated by an experienced linguist across three complementary dimensions: (1) metadata, (2) subjects of discussion, and (3) voting outcomes, totaling over 38,000 individual annotations. Released under FAIR principles and accompanied by baseline results on metadata extraction, topic classification, and vote labeling, CitiLink-Minutes demonstrates its potential for downstream NLP and IR tasks, while promoting transparent access to municipal decisions.

Rachma Lutfiny Putri, Freek Colombijn

Gender differences in the work of female and male waste pickers have often been overlooked. In this article we want to show that for waste pickers in Indonesia there are remarkable similarities between female and male waste pickers. At first sight, there is practically no division of tasks between female and male waste pickers. Nevertheless, the domestic chores of women, gendered differences in stigmatisation, and possible societal expectations about the compatibility of waste picking with femininity do seriously hamper their work as waste pickers. A better understanding of how waste picking is done is important because the activity is one step in recycle chains in the Global South. The article also warns against the generic use of the term ‘waste picker’ without carefully distinguishing between their different roles in the municipal waste management assemblage.

Dulce W. González-Martínez, Alma D. Casas-Rodríguez, Sergio A. Coronado-Contreras et al.

Black beans (<i>Phaseolus vulgaris</i> L.) are one of the most consumed legumes worldwide. Black beans are rich in proteins, vitamins, minerals, and polyphenolic compounds. The present study aims to valorize black beans for the extraction of polyphenolic compounds using solid-state fermentation (SSF) from <i>Aspergillus niger</i> GH1. A physicochemical analysis of black beans was performed. Fermentation kinetics was performed to establish the best accumulation time of condensed polyphenols. A two-level Plackett–Burman experimental design was used to evaluate the culture conditions (temperature, humidity, inoculum, particle size, pH and salt concentration) for the accumulation of condensed polyphenols. The results of the physicochemical analysis showed that black beans can be used as a substrate in the SSF process. In addition, the best time for the accumulation of condensed polyphenols was 48 h. Treatment 5 achieved an accumulation of 21.04 mg/g of condensed polyphenols. While the factors of particle size, humidity, and temperature had a significant effect on the accumulation of condensed polyphenols. It is concluded that the SSF process is an efficient and eco-friendly extraction method for obtaining bioactive molecules with potential applications in the pharmaceutical, food, and cosmetic industries.

Alice Waithaka, Sofia Plakantonaki, Kyriaki Kiskira et al.

Plastic materials are widely used for packaging due to their versatility and availability. Global production, mainly from petrochemicals, is estimated at 380 million tons, increasing annually by 4%. Packaging plastics have the shortest lifespan and contribute significantly to environmental pollution. Current production, use, and disposal of these plastics harm the environment, hu-mans, and ecosystems. Microplastics, (plastics particles ranging from 1 µm to 5 mm) formed through degradation, accumulate in ecosystems and the human body, including the brain. Bioplastics and biodegradable polymers from biological sources are a sustainable alternative; however, most production still relies on food crops, raising concerns about food security and sustainability. Utilizing organic wastes reduces production costs, lessens pressure on food systems, and supports waste management efforts. Cellulose, an abundant natural polymer, offers strong potential due to biodegradability, availability, and mechanical properties. This review explores extracting cellulose from banana pseudostem waste for packaging, high-lighting extraction and conversion methods and characterization via FTIR, TGA, SEM, XRD, and mechanical testing. FTIR confirmed the effective removal of lignin and hemicellulose, XRD revealed increased crystallinity corresponding to Type I cellulose, SEM showed a roughened fiber surface after alkaline treatment, and TGA indicated high thermal stability up to 250 °C. The goal is eco-friendly packaging by promoting agrowaste use. Further research should improve performance and scalability of cellulose-based bioplastics to meet industry needs and compete effectively with conventional plastics.

Fotini Drosou, Tryfon Kekes, Athanasios Kardamanidis et al.

The juice industry generates substantial quantities of solid waste and wastewater. Consequently, efforts have focused on their treatment and valorization to obtain high-value-added products. Traditionally, these wastes are managed through landfill disposal and treatment in municipal wastewater facilities, respectively. In the present work, two alternative scenarios for the valorization of orange juice waste were developed and assessed in comparison to the conventional approach by performing a Life Cycle Assessment (LCA). Scenario 1 involved hydro-distillation of solid waste for essential oil recovery, followed by anaerobic digestion for biogas and fertilizer production, with wastewater treated via membrane filtration and chlorination. In Scenario 2, solvent-free microwave extraction (SFME) was employed for essential oil recovery, followed by anaerobic digestion. Wastewater was treated in a membrane bioreactor followed by ultraviolet treatment. According to the results, Scenario 1 achieved a 36% reduction in greenhouse gas emissions due to the beneficial effects of biogas and fertilizer production, despite its high energy demands. Scenario 2 exhibited the best environmental performance due to lower energy demands and higher extraction efficiency compared to Scenario 1, with reductions of 46% in greenhouse gas emissions and 48% in resource depletion. Overall, the findings highlight the potential of integrating innovative, energy-efficient technologies for the sustainable valorization of juice industry waste, offering measurable environmental advantages for industrial-scale implementation.

Saskia Abrahms-Kavunenko

The ever-increasing abundance and expanding affordances of plastics have come to instantiate modernity through their successes and failures in usage and beyond. Materially, plastics have a capacity to stubbornly endure yet simultaneously to fracture. Grounded in ethnographic fieldwork on an Indian Ocean island, this article will explore the heritage of plastic objects in their shattering and dispersal. The novel presence and ubiquity of plastics have caused some scholars to propose that the presence of plastics could constitute a possible marker of the Anthropocene. Yet plastics won’t stay in their own epoch. Microplastics can migrate and infuse sedimentary layers from previous eras, shimmying down to earlier stratigraphic layers and complicating the very knowability of the past. This paper will look at the temporal vertiginousness of the current epoch through the recalcitrance of human-made materials, arguing that, even in their material remnants, plastics radically complicate the delineation and understanding of geological time.

Jerry Xu, Justin Wang, Joley Leung et al.

There are a growing number of AI applications, but none tailored specifically to help residents answer their questions about municipal budget, a topic most are interested in but few have a solid comprehension of. In this research paper, we propose GRASP, a custom AI chatbot framework which stands for Generation with Retrieval and Action System for Prompts. GRASP provides more truthful and grounded responses to user budget queries than traditional information retrieval systems like general Large Language Models (LLMs) or web searches. These improvements come from the novel combination of a Retrieval-Augmented Generation (RAG) framework ("Generation with Retrieval") and an agentic workflow ("Action System"), as well as prompt engineering techniques, the incorporation of municipal budget domain knowledge, and collaboration with local town officials to ensure response truthfulness. During testing, we found that our GRASP chatbot provided precise and accurate responses for local municipal budget queries 78% of the time, while GPT-4o and Gemini were only accurate 60% and 35% of the time, respectively. GRASP chatbots greatly reduce the time and effort needed for the general public to get an intuitive and correct understanding of their town's budget, thus fostering greater communal discourse, improving government transparency, and allowing citizens to make more informed decisions.

Wenbo Pan, Jie Xu, Qiguang Chen et al.

Large Language Models (LLMs) should refuse to answer questions beyond their knowledge. This capability, which we term knowledge-aware refusal, is crucial for factual reliability. However, existing metrics fail to faithfully measure this ability. On the one hand, simple refusal-based metrics are biased by refusal rates and yield inconsistent scores when models exhibit different refusal tendencies. On the other hand, existing calibration metrics are proxy-based, capturing the performance of auxiliary calibration processes rather than the model's actual refusal behavior. In this work, we propose the Refusal Index (RI), a principled metric that measures how accurately LLMs refuse questions they do not know. We define RI as Spearman's rank correlation between refusal probability and error probability. To make RI practically measurable, we design a lightweight two-pass evaluation method that efficiently estimates RI from observed refusal rates across two standard evaluation runs. Extensive experiments across 16 models and 5 datasets demonstrate that RI accurately quantifies a model's intrinsic knowledge-aware refusal capability in factual tasks. Notably, RI remains stable across different refusal rates and provides consistent model rankings independent of a model's overall accuracy and refusal rates. More importantly, RI provides insight into an important but previously overlooked aspect of LLM factuality: while LLMs achieve high accuracy on factual tasks, their refusal behavior can be unreliable and fragile. This finding highlights the need to complement traditional accuracy metrics with the Refusal Index for comprehensive factuality evaluation.

Federico Gibellini, Piero Fraternali, Giacomo Boracchi et al.

Improper solid waste management represents both a serious threat to ecosystem health and a significant source of revenues for criminal organizations perpetrating environmental crimes. This issue can be mitigated thanks to the increasing availability of Very-High-Resolution Remote Sensing (VHR RS) images. Modern image-analysis tools support automated photo-interpretation and large territory scanning in search of illegal waste disposal sites. This paper illustrates a semi-automatic waste detection pipeline, developed in collaboration with a regional environmental protection agency, for detecting candidate illegal dumping sites in VHR RS images. To optimize the effectiveness of the waste detector at the core of the pipeline, extensive experiments evaluate such design choices as the network architecture, the ground resolution and geographic span of the input images, as well as the pretraining procedures. The best model attains remarkable performance, achieving 92.02 % F1-Score and 94.56 % Accuracy. A generalization study assesses the performance variation when the detector processes images from various territories substantially different from the one used during training, incurring only a moderate performance loss, namely an average 5.1 % decrease in the F1-Score. Finally, an exercise in which expert photo-interpreters compare the effort required to scan large territories with and without support from the waste detector assesses the practical benefit of introducing a computer-aided image analysis tool in a professional environmental protection agency. Results show that a reduction of up to 30 % of the time spent for waste site detection can be attained.

Maria Râpă, Raluca Nicoleta Darie-Niță, George Coman

This review aims to streamline the approach to assessing the most used valorization methods for fruit and vegetable waste (FVW) that are eco-friendly, cost-effective, and sustainable within a circular economy framework. Green processing technologies for the extraction of bioactive compounds from FVW, their applications, and the technico-economical assessment of FVW’ biorefinery to support circular economy are highlighted. Important value-added products generated by FVW include bioactive compounds, pectin, protein isolates, such as soy, natural pigments such as anthocyanins, quinones, carotenoids, betalains, and chlorophyll. At this time, the prospects of using FVW have increased in the food supplements, bioactive and edible food packaging, agriculture, energy, and water purification fields. The findings report that proper management of FVW not only minimizes their addition to landfills in the absence of composting, but also promotes the efficient utilization of resources for the development of innovative materials with a wide range of beneficial applications. Implementing the possible solutions described in this paper would not only reduce environmental impact, but also open up new economic opportunities through the valorization of FVW.

Eduardo Kloeckner Sbardelotto, Karyne Ferreira dos Santos, Isabel Milagre Martins et al.

Concrete waste recycling processes involve multiple stages, equipment, and procedures which produce Fine Recycled Concrete Aggregates (FRCA) for use in construction. This research aims at performing a comprehensive overview of the recycling technologies, recycling processes, and normative requirements to produce high-quality FRCA and to investigate the influence of these processes on their physical properties. The properties investigated were the particle size distribution (PSD), water absorption, oven-dry density, and adhered paste. The correlations between these properties were also investigated. The results indicate that the recycling processes with the highest potential for producing high-quality aggregates demand jaw crusher and impact crusher combinations. These processes are better suited for achieving FRCA with the desired particle size distribution and oven-dry density. However, water absorption and adhered paste, which are critical factors for obtaining high-quality FRCA, seem to be more dependent on the original material than on the recycling process.

Zakariae Belmokhtar, Simon Sanchez-Diaz, Patrice Cousin et al.

This study investigates the potential for recycling fishing rope waste from the Magdalen Islands, Canada, into sustainable wall cladding panels, addressing both environmental concerns and waste management challenges. A comprehensive characterization of the fishing ropes was conducted using various analytical techniques to assess their suitability for recycling. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) identified polyethylene (PE) and isotactic polypropylene (iPP) as the main polymers present in the ropes, with a composition of approximately 25% PE and 75% PP. The effects of photodegradation were evaluated through carbonyl index analysis, differential scanning calorimetry (DSC), tensile testing, and gel permeation chromatography (GPC). The results showed reduced crystallinity, a 20% decrease in tensile strength, and lower molecular weights due to environmental exposure in comparison with unused ropes. However, melt flow rate (MFR) measurements aligned with virgin HDPE and PP values used in rope manufacturing, indicating suitable processability for recycling. Panels produced from recycled fishing ropes exhibited lower flexural and impact properties compared to commercial alternatives due to the presence of mineral contaminants and voids in the panels as revealed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). This comprehensive investigation provides valuable insights into the potential repurposing of fishing rope waste, contributing to the development of sustainable waste management strategies for coastal communities.

Qian Hui Tan, Brenda S.A. Yeoh

This paper seeks to redress the over-emphasis on state-driven circular policies in public and academic discourses by attending to two physical community-based freecycling markets at the emerging frontiers of circular waste/resource management in Singapore. Freecycling markets that close short reuse loops are a counterpoint to policies that close long recycling loops. Drawing primarily on empirical data from ethnographic fieldwork, we argue that freecycling markets exemplify a sustainable materialist movement concerned about the sustainability of material resources vis-a-vis the closing/shortening of material circularity loops. This is achieved through the reconfiguration of (a) material flows and (b) material relations. The redirection of unwanted but reusable household objects away from the incinerator and towards potential reusers animates a shift from a linear to circular material flow. We contend that this redirection of material resources for reuse is augmented by rescue and recirculation, which are relatively neglected within the scholarship on circular R-behaviours. Additionally, freecycling markets seek to transform material relations by encouraging care and stewardship, instead of use and disposal. Crucially, we highlight how freecycling markets may be plagued with material constraints that render them not-so-sustainable-and-scalable, thereby shedding light on the practical limits of sustainable materialist action. Taken together, this paper extends the scholarship on circular economies by bringing work on sustainable materialism into a productive dialogue with that on circular activisms and R-behaviours.

Yan Zhang, Yixiang Tian, Lin Chen

One type of bond with the most implicit government guarantee is municipal investment bonds. In recent years, there have been an increasing number of downgrades in the credit ratings of municipal bonds, which has led some people to question whether the implicit government guarantee may affect the objectivity of the bond ratings? This paper uses text mining methods to mine relevant policy documents related to municipal investment bond issuance, and calculates the implicit guarantee strength of municipal investment bonds based on the PMC index model. It further analyzes the impact of the implicit guarantee strength of municipal bonds on their credit evaluation. The study found that the implicit government guarantee on municipal investment bonds does indeed help to raise the credit ratings assigned by credit rating agencies. The study found that, moreover, the government's implicit guarantee has a more pronounced effect in boosting credit ratings in less developed western regions.

Baridhi Malakar

I examine whether the imposition of fiduciary duty on municipal advisors affects bond yields and advising fees. Using a difference-in-differences analysis, I show that bond yields reduce by $\sim$9\% after the imposition of the SEC Municipal Advisor Rule due to lower underwriting spreads. Larger municipalities are more likely to recruit advisors after the rule is effective and experience a greater reduction in yields. However, smaller issuers do not experience a reduction in offering yields after the SEC Rule. Instead, their borrowing cost increases if their primary advisor exits the market. Using novel hand-collected data, I find that the average advising fees paid by issuers does not increase after the regulation. Overall, my results suggest that while fiduciary duty may mitigate the principal-agent problem between some issuers and advisors, there is heterogeneity among issuers.

Neel Jain, Aditya Shrivastava, Chenyang Zhu et al.

A key component of building safe and reliable language models is enabling the models to appropriately refuse to follow certain instructions or answer certain questions. We may want models to output refusal messages for various categories of user queries, for example, ill-posed questions, instructions for committing illegal acts, or queries which require information past the model's knowledge horizon. Engineering models that refuse to answer such questions is complicated by the fact that an individual may want their model to exhibit varying levels of sensitivity for refusing queries of various categories, and different users may want different refusal rates. The current default approach involves training multiple models with varying proportions of refusal messages from each category to achieve the desired refusal rates, which is computationally expensive and may require training a new model to accommodate each user's desired preference over refusal rates. To address these challenges, we propose refusal tokens, one such token for each refusal category or a single refusal token, which are prepended to the model's responses during training. We then show how to increase or decrease the probability of generating the refusal token for each category during inference to steer the model's refusal behavior. Refusal tokens enable controlling a single model's refusal rates without the need of any further fine-tuning, but only by selectively intervening during generation.

M. Alfè, V. Gargiulo, M. Porto et al.

Refuse-Derived Fuels (RDFs) are segregated forms of wastes obtained by a combined mechanical–biological processing of municipal solid wastes (MSWs). The narrower characteristics, e.g., high calorific value (18–24 MJ/kg), low moisture content (3–6%) and high volatile (77–84%) and carbon (47–56%) contents, make RDFs more suitable than MSWs for thermochemical valorization purposes. As a matter of fact, EU regulations encourage the use of RDF as a source of energy in the frameworks of sustainability and the circular economy. Pyrolysis and gasification are promising thermochemical processes for RDF treatment, since, compared to incineration, they ensure an increase in energy recovery efficiency, a reduction of pollutant emissions and the production of value-added products as chemical platforms or fuels. Despite the growing interest towards RDFs as feedstock, the literature on the thermochemical treatment of RDFs under pyrolysis and gasification conditions still appears to be limited. In this work, results on pyrolysis and gasification tests on a real RDF are reported and coupled with a detailed characterization of the gaseous, condensable and solid products. Pyrolysis tests have been performed in a tubular reactor up to three different final temperatures (550, 650 and 750 °C) while an air gasification test at 850 °C has been performed in a fluidized bed reactor using sand as the bed material. The results of the two thermochemical processes are analyzed in terms of yield, characteristics and quality of the products to highlight how the two thermochemical conversion processes can be used to accomplish waste-to-materials and waste-to-energy targets. The RDF gasification process leads to the production of a syngas with a H2/CO ratio of 0.51 and a tar concentration of 3.15 g/m3.

P. Caputo, P. Calandra, V. Loise et al.

The production and maintenance of road pavements consume resources and produce wastes that are disposed of in landfills. To make more sustainable this activity, we have envisioned a method based on a circular use of residues (oil and char) from municipal solid waste pyrolysis as useful additives for producing improved asphalts and for recycling old asphalts to generate new ones, reducing at the same time the consumption of resources for the production of new road pavements and the disposal of wastes to landfills. This work aims to show the feasibility of the integration of two processes (thermal treatment of municipal solid waste on one side, and that of road pavement production on the other side) where the products deriving from waste pyrolysis become added-value materials to improve the quality of road pavements. In this contribution, we presented the effect of pyrolysis product addition on asphalt binder (bitumen) preparation and aging. Solid and liquid products, deriving from the pyrolysis of two kinds of wastes (refused derived fuel (RDF) and granulated rubber tyre waste), have been used for the preparation of asphalt binder samples. Rheological tests have been performed to determine the mechanical properties of neat asphalt binder (bitumen) and those enriched with pyrolysis derived products. Measurements to evaluate possible anti-aging effects have been also performed. The collected results indicate that char addition strengthens the overall bitumen intermolecular structure while bio-oil addition exerts a rejuvenating activity.