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1.
Biomater Adv ; 138: 212961, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35913244

RESUMO

From the last few decades, the usage of polycarbonate (PC) has tremendously increased due to its engineering properties such as outstanding mechanical strength, superior toughness, and good optical transparency. Owning to these properties, PC has widespread applications in the field of electronics, construction, data storage, automotive industry and subsequently resulted in an ever-increasing volume of post-consumer PC e-waste, which also increases the environmental pollution with time due to its nonbiodegradability nature. Therefore, recycling of PC has become a significant challenge throughout the globe. Herein, we first time reported synthesis of a family of low-cost biodegradable and biocompatible biopolymers using solvent and catalyst free melt polycondensation reaction of recycled PC e-waste derived monomer bis(hydroxyethyl ether) of bisphenol A (BHEEB) along with other renewable resources such as sebacic acid, citric acid and mannitol. The synthesis of the polyester was confirmed by FTIR spectroscopy, NMR spectroscopy, XRD and DSC. The mechanical properties and biodegradation behaviour of the polyester can be fine-tuned by simply varying the monomer feed ratio. In addition to that, the polyester demonstrated excellent shape memory property in ambient temperature along with outstanding recovery properties. In addition to this, the synthesized polyester showed exceptional in vitro and in vivo cytocompatibility as well as cell proliferation rate against mouse fibroblast cells (NIH-3 T3) and biocompatibility, respectively. Therefore, the novel polyesters derived from recycled PC e-waste may be potential resorbable biomaterial for tissue engineering applications in future.


Assuntos
Resíduo Eletrônico , Poliésteres , Animais , Camundongos , Cimento de Policarboxilato , Reciclagem
2.
Nat Commun ; 13(1): 4497, 2022 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-35922415

RESUMO

Supramolecular chemical strategies for Rare Earth (RE) element separations are emerging which amplify the small changes in properties across the series to bias selectivity in extraction or precipitation. These advances are important as the REs are crucial to modern technologies yet their extraction, separation, and recycling using conventional techniques remain challenging. We report here a pre-organised triamidoarene platform which, under acidic, biphasic conditions, uniquely and selectively precipitates light RE nitratometalates as supramolecular capsules. The capsules exhibit both intra- and intermolecular hydrogen bonds that dictate selectivity, promote precipitation, and facilitate the straightforward release of the RE and recycling of the receptor. This work provides a self-assembly route to metal separations that exploits size and shape complementarity and has the potential to integrate into conventional processes due to its compatibility with acidic metal feed streams.


Assuntos
Metais Terras Raras , Cápsulas , Reciclagem/métodos
3.
Artigo em Inglês | MEDLINE | ID: mdl-35805575

RESUMO

The recycling of solid waste resources can effectively alleviate resource shortages and environmental pollution and can promote the sustainable development of an ecological economy and green economy. Therefore, China has set up a series of recycling policies. In order to promote the development of China's solid waste resource recycling industry, and to be able to set up and implement correct policy documents according to real-time dynamics, this study uses NVivo software to analyze the content of 10 Core Journals' documents screened from the China HowNet database and sets up three node classifications and four partition dimensions to build a three-dimensional model for qualitative analysis and emotional analysis. The analysis determines the existing weaknesses of China's solid waste resource recycling policy under four dimensions and puts forward prospects for its future from these four aspects of system, capacity, measures and environment.


Assuntos
Resíduos Sólidos , Gerenciamento de Resíduos , China , Poluição Ambiental , Indústrias , Formulação de Políticas , Reciclagem , Resíduos Sólidos/análise , Gerenciamento de Resíduos/métodos
4.
Artigo em Inglês | MEDLINE | ID: mdl-35805621

RESUMO

Exposure to lead in environmental and occupational settings continues to be a serious public health problem. At environmentally relevant doses, two mechanisms may underlie lead exposition-induced genotoxicity, disruption of the redox balance and an interference with DNA repair systems. The aim of the study was to evaluate the ability of lead exposition to induce impaired function of Ape1 and its impact on DNA repair capacity of workers chronically exposed to lead in a battery recycling plant. Our study included 53 participants, 37 lead exposed workers and 16 non-lead exposed workers. Lead intoxication was characterized by high blood lead concentration, high lipid peroxidation and low activity of delta-aminolevulinic acid dehydratase (δ-ALAD). Relevantly, we found a loss of DNA repair capacity related with down-regulation of a set of specific DNA repair genes, showing specifically, for the first time, the role of Ape1 down regulation at transcriptional and protein levels in workers exposed to lead. Additionally, using a functional assay we found an impaired function of Ape1 that correlates with high blood lead concentration and lipid peroxidation. Taken together, these data suggest that occupational exposure to lead could decrease DNA repair capacity, inhibiting the function of Ape1, as well other repair genes through the regulation of the ZF-transcription factor, promoting the genomic instability.


Assuntos
Intoxicação por Chumbo , Exposição Ocupacional , Reparo do DNA , Humanos , Chumbo/toxicidade , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/análise , Sintase do Porfobilinogênio , Reciclagem
5.
Artigo em Inglês | MEDLINE | ID: mdl-35805661

RESUMO

The purpose of this study is to determine whether there are gender differences in people's pro-environmental psychology and behaviors in China. An online survey was conducted with the snowball sampling technique, and a sample of 532 Chinese respondents was obtained for the research. This study finds that gender does affect green psychology and behaviors, with females reporting a higher level of environmentalism in China. Specifically, females are more concerned with environmental problems, more supportive of plastic ban policies, more positive towards reducing plastics (reduce), and have stronger intention to bring a reusable bag for shopping (reuse and recycle). Moreover, females use fewer disposable toiletries when checking in a hotel and require less disposable tableware when ordering takeout. This study contributes to the current literature by identifying the relationship between gender and environmentalism in China. Implications for anti-plastic policy design and environmental management are also presented.


Assuntos
Intenção , Reciclagem , China , Feminino , Humanos , Plásticos , Inquéritos e Questionários
6.
J Environ Public Health ; 2022: 8391616, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35855815

RESUMO

Unwanted remains, discarded residues, and byproduct materials that are not required by the initial user are known as wastes. In Ethiopia, improper solid waste management becomes endemic and it affects the health conditions, comforts, and freedom of town communities. Improper solid waste management can also adversely affect infrastructure damages, socioeconomic conditions, and environmental and health problems. So, awareness creation among the communities is necessary. The main objective of the study was to assess the management of existing solid waste activities and reverse logistic systems in Tepi town. The impacts of improper solid waste management were reduced through waste accumulation, transportation, recycling, and waste removal. Available pieces of information for the study were gathered from 450 near house places and 549 survivals. The collected data were analyzed by using Vensim system dynamics software, and the obtained results were modeled by a system dynamic cause and effect relationship diagram. Finally, the appropriate recommendations for communities, municipals, and institutions were provided.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Cidades , Reciclagem , Eliminação de Resíduos/métodos , Resíduos Sólidos/análise , Gerenciamento de Resíduos/métodos
7.
Artigo em Inglês | MEDLINE | ID: mdl-35886358

RESUMO

Great efforts have been exerted in reducing carbon emissions in design, construction and operation stages. However, little attention is paid to the quantification of carbon emissions in construction waste recycling at the end-of-life stage. This study aims to quantitatively analyze the carbon emission of construction waste in Shanghai City, PR China. A grey model is used to forecast the generation amount of construction waste, and a life cycle assessment is performed to estimate the carbon emission of construction waste. In this study, both the carbon emission of recycling activities (environmental costs), and the equivalent amount of carbon generated from alternative materials (environmental benefit) are considered. Here, recycling 1 ton (t) of construction waste in Shanghai can save 100.4 kg CO2-e. The total carbon-emission-saving potential can be increased from 0.31 million t CO2-e (2022) to 0.35 million t CO2-e (2031). The carbon emission of recycling concrete, brick, steel, wood and mortar, identified as the key components of construction waste, is investigated. This research can help to reduce carbon emissions and further achieve carbon neutrality for Shanghai City. The proposed methods can also be applied to other regions, especially when the data for construction waste are insufficient.


Assuntos
Indústria da Construção , Gerenciamento de Resíduos , Animais , Carbono , Dióxido de Carbono , China , Indústria da Construção/métodos , Materiais de Construção , Estágios do Ciclo de Vida , Reciclagem/métodos , Gerenciamento de Resíduos/métodos
8.
Artigo em Inglês | MEDLINE | ID: mdl-35886477

RESUMO

BACKGROUND: Child labor remains a health hazard, affecting the mental, physical, and emotional well-being of children. Children engage in waste management through various channels while constantly working to create a healthier and cleaner environment and exposing themselves to numerous health risks. Thus, this scoping review aims to explore the occupational injuries, health hazards, and sufferings of child waste workers in South Asia. METHODS: Following the PRISMA guidelines, a scoping review of available relevant scientific literature was completed to comprehensively analyze the extent of child waste workers' health suffering. Online databases PubMed, SCOPUS, and Google Scholar were searched for predefined criteria. Collected references were screened with Rayyan web tools and Endnote. Based on study inclusion criteria, a thematic synthesis was performed on the findings of 12 articles. RESULTS: This study's findings provided deep insights into the most prevalent occupational health sufferings among child waste workers, as depicted in the available literature. Prevalence of injuries like cuts and wounds was found predominant. These injuries are caused by the collection, transportation, dumping, and recycling of waste. Respiratory, musculoskeletal, and skin diseases are more prevalent among child waste worker children than in control groups of the same socioeconomic backgrounds. A higher chance of genetic or neuro-degenerative disorder and DNA mutation indicates a long-term effect on the children working in the waste management sector. Psychological sufferings were the least explored, although very common among child laborers. MPD (Minor Psychiatric Disorder) was very high among waste workers. Regarding healthcare-seeking behavior, traditional methods are preferable rather than formal health facilities. More research is required in this area due to a lack of evidence on the health problems of child waste workers. CONCLUSIONS: Occupational hazards were myriad among child waste workers. Though many children are involved in waste management, they are typically excluded from mainstream child protection and support systems, making them more exposed to occupational harassment and injury. Policymakers should design specific programs for these vulnerable groups considering the issues below, i.e., provide protective equipment such as facemasks, gloves, footwear, and rag sorting tools to safeguard them from physical damage and illness, ensure access to health care, to school, and provide basic nutrients to them. Furthermore, the authorities should think of alternative income generating programs for these groups of children.


Assuntos
Saúde do Trabalhador , Traumatismos Ocupacionais , Gerenciamento de Resíduos , Ásia/epidemiologia , Criança , Humanos , Traumatismos Ocupacionais/epidemiologia , Reciclagem
9.
Artigo em Inglês | MEDLINE | ID: mdl-35886620

RESUMO

Current industrial development has led to an increase in sulfate-rich industrial sewage, threatening industrial ecology and the environment. Incorrectly treating high-concentration sulfate wastewater can cause serious environmental problems and even harm human health. Water with high sulfate levels can be treated as a resource and treated harmlessly to meet the needs of the circular economy. Today, governments worldwide are working hard to encourage the safe disposal and reuse of industrial salt-rich wastewater by recycling sulfate-rich wastewater (SRW) resources. However, the conflict of interests between the SRW production department, the SRW recycling department, and the governments often make it challenging to effectively manage sulfate-rich wastewater resources. This study aims to use the mechanism of evolutionary game theory (EGT) to conduct theoretical modelling and simulation analysis on the interaction of the behaviour of the above three participants. This paper focuses on the impact of government intervention and the ecological behaviour of wastewater producers on the behavioural decisions of recyclers. The results suggest that the government should play a leading role in developing the SRW resource recovery industry. SRW producers protect the environment in the mature stage, and recyclers actively collect and recover compliant sulfate wastewater resources. Governments should gradually deregulate and eventually withdraw from the market. Qualified recyclers and environmentally friendly wastewater producers can benefit from a mature SRW resources recovery industry.


Assuntos
Sulfatos , Águas Residuárias , Teoria do Jogo , Humanos , Reciclagem , Esgotos , Sulfatos/análise , Óxidos de Enxofre , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/análise
10.
PLoS One ; 17(7): e0265889, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35905045

RESUMO

Waste picker organisations (WPOs) around the globe collect, transport and process waste to earn their living but represent a widely excluded, marginalised and impoverished segment of society. WPOs are highly innovative, created by grassroots out of "nothing" to deliver economic, social and environmental sustainability. Still, we do not know how such innovations are developed, and how they are disseminated and adopted by other groups. This article examines characteristics, challenges and innovations of WPOs across five countries in Latin America and East Africa. It is based on quantitative and qualitative data regarding modes of organisation and management, gender, received support, business orientations, environmental and social contributions, and innovations developed in response to multiple challenges. The paper provides a comprehensive understanding of WPOs' activities and their grassroots innovations in the Global South. The study shows how WPOs contribute significantly to the economic, social and environmental sustainability of the societies they serve as well as the wider urban societies. To start and maintain WPOs in informal settlements with a lack of infrastructure, institutional frameworks, and public and private investors is a difficult quest. WPOs take many different organisational forms depending on the complexity of local realities, ranging from advanced collective organization as cooperatives to small self-help groups and microentrepreneurs. Self-organisation into regional and national networks provides economic opportunities, autonomy and stability as well as political influence. Yet, institutional support is fundamental and the lack thereof threatens their existence. Sustaining WPOs as important providers of socio-environmental benefits through governmental and non-governmental actions is a worthwhile undertaking that builds sustainability.


Assuntos
Reciclagem , Eliminação de Resíduos , África Oriental , Renda , América Latina , Organizações
11.
An Acad Bras Cienc ; 94(3): e20210207, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35857960

RESUMO

Urban Solid Waste Management (USWM) is one of the components that influences in the sustainable cities. It is a fundamental factor in achieving the Sustainable Development Goals (SDGs), 2030 agenda. This paper work aims to validate a mathematical model for solid waste generation and to estimate the economic loss due lack of recycling in the city of Campo Grande, State of Mato Grosso do Sul/Brazil. The model adopted was developed by Dias et. al. (2012), which allows projecting the mass of waste to be generated by the inhabitants from socioeconomic indicators, such as per capita income, social classes and size of population in a specific urban territory. Besides, waste composition was analyzed to determinate the value and share of the gravimetric characterization, in order to estimate the economic loss in areas, which there are no selective collection of Household Solid Waste (HSW). The model showed strong adherence, when compared to the real mass of HSW collected. The economic loss due to selective collection approaches nearly 9.6 million US$, or about 11 US$ per person per year. The study can provide support for economic evaluation of project sand public policies related to USWM executed in any other city with similar characteristics.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Cidades , Humanos , Modelos Teóricos , Reciclagem , Resíduos Sólidos
12.
Environ Pollut ; 308: 119704, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35792296

RESUMO

Recycling of electronic waste (e-waste) and inevitable pollution under current technology have always been a concern of people. Generation and release of pollutants in the recycling process of e-waste are closely related to processing technology and equipment. In this paper, the pollution characteristics of different functional areas and critical processing units in formal e-waste dismantling base have been studied systematically and comprehensively. The results showed that the overall pollutants concentration in crushing workshop and cathode ray tube (CRT) monitor disposing workshop are much higher than other functional areas. Screen-cone glass separation for CRT monitor was the processing unit with the greatest exposure risk and the hazard index (HI) of Pb was 4.60. Pollutant emission factor of the main processing units was calculated and the waste printed circuit board (WPCB) crushing was the most polluted unit. Appropriate improvements in technology and equipment can effectively reduce the generation and release of pollutants. Some reasonable prospects about intelligent equipment and special technologies were proposed for e-waste disposal. All the results provided theoretical and data support for pollution control and technology upgrade of the formal e-waste dismantling base.


Assuntos
Resíduo Eletrônico , Poluentes Ambientais , Eliminação de Resíduos , Poluentes Ambientais/análise , Humanos , Reciclagem/métodos , Tecnologia
13.
Sci Rep ; 12(1): 10236, 2022 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-35764782

RESUMO

Achieving carbon neutrality requires a variety of technological approaches. In the present study, we confirmed the applicability of a carbon cycle system in several industrial fields using sulphur-oxidising bacteria. This system produces a nitrogen fertiliser, which decreases carbon emissions by recycling H2S and NH3 pollutants discharged into the atmosphere or wastewater. It should be considered in industrial fields as a carbon reduction strategy.


Assuntos
Sequestro de Carbono , Reciclagem , Bactérias , Carbono , Águas Residuárias
14.
Artigo em Inglês | MEDLINE | ID: mdl-35742611

RESUMO

The environmental pollution caused by logistics packaging in China has attracted increasing attention in recent years, and circular packaging is considered an effective means to solve the aforementioned problem. Therefore, this study considers the uncertainty of the external environment; constructs a stochastic game model of circular logistics-packaging promotion, which consists of environmental regulators, logistics enterprises, and consumers; collects data related to logistics packaging in China to describe the current circular-packaging promotion dilemma; and conducts a parameter-sensitivity analysis. The results show that (1) after a short period of fluctuation, the environmental regulator will lock in the "strong regulation" strategy, whereas logistics enterprises and consumers will quickly lock in the "no promotion" and "negative use" strategies. (2) The change in the initial probability will affect the rate of strategy evolution of the gaming system. (3) The "strong regulatory" strategy of environmental regulators and the increase in the number of circular-packaging cycles can help establish a logistics-recycling-packaging system. (4) The increase in recycling incentives can cause consumers to shift toward "active use" strategies, but this has accelerated the rate at which logistics companies lock into "no promotion" strategies. (5) The increase in the intensity of random interference will raise the fluctuation of the evolution of the game subject. For logistics enterprises, moderate random interference helps them evolve toward the "promotion" strategy.


Assuntos
Gerenciamento de Resíduos , China , Embalagem de Produtos , Reciclagem , Gerenciamento de Resíduos/métodos
15.
Artigo em Inglês | MEDLINE | ID: mdl-35742614

RESUMO

The construction industry is developing rapidly along with the acceleration of urbanization but accompanied by an increased amount of construction and demolition waste (CDW). From the perspective of sustainability, the existing research has mainly focused on CDW treatment or landfill disposal, but the challenge of reverse logistics of CDW recycling that provides overall CDW route planning for multiple participants and coordinates the transportation process between multiple participants is still unclear. This paper develops an optimization model for multi-depot vehicle routing problems with time windows (MDVRPTW) for CDW transportation that is capable of coordinating involved CDW participants and suggesting a cost-effective, environment-friendly, and resource-saving transportation plan. Firstly, economic cost, environmental pollution, and social impact are discussed to establish this optimization-oriented decision model for MDVRPTW. Then, a method combined with a large neighborhood search algorithm and a local search algorithm is developed to plan the transportation route for CDW reverse logistics process. With the numerical experiments, the computational results illustrate the better performance of this proposed method than those traditional methods such as adaptive large neighborhood search algorithm or adaptive genetic algorithm. Finally, a sensitivity analysis considering time window, vehicle capacity, and carbon tax rate is conducted respectively, which provides management implications to support the decision-making of resource utilization maximization for enterprises and carbon emission management for the government.


Assuntos
Indústria da Construção , Gerenciamento de Resíduos , Carbono , Indústria da Construção/métodos , Materiais de Construção , Humanos , Resíduos Industriais/análise , Reciclagem/métodos , Gerenciamento de Resíduos/métodos
16.
Artigo em Inglês | MEDLINE | ID: mdl-35742631

RESUMO

Extensive construction augmenting the infrastructure and real estate projects underpin Saudi Arabia's Vision 2030 of sustainable cities. A part of this struggle involves the transformation of the existing infrastructure together with new construction, which generates a large amount of construction and demolition waste (CDW). In the absence of a structured life cycle assessment (LCA) framework, the waste management companies are planning future scenarios (phased expansions of material recovery facilities to improve the recycling rate) primarily on economic grounds. This study assesses the environmental impacts of the existing and planned CDW management practices of the Saudi Investment Recycling Company in Riyadh City by dint of LCA. Impact 2002+ performs life cycle impact assessment of the base case (45% recycling), four treatments (61, 76, 88, and 100% recycling), and zero waste scenarios. The study demonstrates the benefits of current CDW (mixed soil, concrete blocks, clay bricks, glazed tiles, and asphalt) recycling in terms of avoided impacts of non-renewable energy, global warming, carcinogens, non-carcinogens, and respiratory inorganics potentially generated by landfilling. For the treatment scenario of 100% recycling, CDW conversion into a wide range of aggregates (0-50 mm) can replace 10-100% virgin aggregates in backfilling, precast concrete manufacturing, encasements and beddings of water mains and sewers, manholes construction, non-load bearing walls, and farm-to-market roads. To achieve long-term economic and environmental sustainability, municipalities need to improve source segregation, handling, and storage practices to enhance the existing (45%) recycling rate to 100% in the next five years and approach the zero-waste scenario by 2030. The findings of the present study motivate the generators for source reduction as well as encourage the recycling companies and concerned organizations in the continuous performance improvement of the CDW management systems across Saudi Arabia on environmental grounds, as an addition to the perceived economic benefits.


Assuntos
Indústria da Construção , Gerenciamento de Resíduos , Animais , Materiais de Construção , Resíduos Industriais , Estágios do Ciclo de Vida , Reciclagem , Arábia Saudita
17.
Artigo em Inglês | MEDLINE | ID: mdl-35742648

RESUMO

To investigate how legal constraints on the recycling rate of used products and carbon trading mechanisms affect the profits and other decisions of supply chain system members, this paper develops and solves a two-cycle game model in which the manufacturer dominates while the retailer takes a secondary position; the manufacturer produces only non-low-carbon new products in the first cycle and both new and low-carbon remanufactured products in the second cycle. Simultaneously, the effects of parameters such as recovery rate, unit carbon trading price, and carbon emission reduction factor on the decision making of members of the supply chain system are also discussed. Finally, the conclusions are verified by numerical analysis: (1) When carbon reduction is low, the manufacturer will choose the highest recycling rate to obtain the highest profit, and when carbon reduction is high, manufacturers tend to choose not to recycle when the minimum recycling rate bound by law harms the interests of manufacturers. (2) Under the implementation of the carbon trading mechanism, the unit carbon trading price affects the profits of the members of the supply chain system depending on the size of the carbon emission reduction, and the two are negatively correlated at lower carbon emission reductions and positively correlated at higher carbon emission reductions. (3) From the perspective of supply chain system members' interests, legal constraints and the existence of carbon trading mechanisms are not always conducive to increasing the margins of members of the supply chain system, both relevant to the size of carbon emission reductions. (4) From the perspective of environmental benefits, supply chain members do not need to pay economic costs in all cases to contribute to environmental benefits, and the existence of minimum recycling rate constraints and carbon trading mechanisms are conducive to achieving carbon reduction targets.


Assuntos
Carbono , Tomada de Decisões , Comércio , Reciclagem
18.
Artigo em Inglês | MEDLINE | ID: mdl-35742757

RESUMO

The rapid pace of innovations and the frequency of replacement of electrical and electronic equipment has made waste printed circuit boards (WPCB) one of the fastest growing waste streams. The frequency of replacement of equipment can be caused by a limited time of proper functioning and increasing malfunctions. Resource utilization of WPCBs have become some of the most profitable companies in the recycling industry. To facilitate WPCB recycling, several advanced technologies such as pyrometallurgy, hydrometallurgy and biometallurgy have been developed. Bioleaching uses naturally occurring microorganisms and their metabolic products to recover valuable metals, which is a promising technology due to its cost-effectiveness, environmental friendliness, and sustainability. However, there is sparse comprehensive research on WPCB bioleaching. Therefore, in this work, a short review was conducted from the perspective of potential microorganisms, bioleaching mechanisms and parameter optimization. Perspectives on future research directions are also discussed.


Assuntos
Resíduo Eletrônico , Resíduo Eletrônico/análise , Eletrônica , Metais/metabolismo , Reciclagem
19.
Front Public Health ; 10: 899705, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35692310

RESUMO

The study of construction and demolition waste (CDW) has attracted more and more attentions with the increasing CDW pollution caused by the large-scale infrastructure construction. This study used the Latent Dirichlet Allocation (LDA) combined with topic intensity to discover hot topics and development trends in the study area of CDW. First, the LDA was used for topic modeling to extract the existing topics from textual data. Second, the topic intensity was calculated for the extracted topics and the numerical values of the topic intensity represented the popularity of the topics. In this study, 4 topics were extracted from 1,849 relevant articles through the LDA modeling and topic intensity calculation. The results showed that the topic of "CDW management" had an upward trend. Topics such as "recycled aggregate," "environmental impact," and "study of CDW on soil" all showed a downward trend. The methods of this study can dig into the topics of CDW study and help scholars to engage in this field for better understanding the prevalence and evolution trends of these topics.


Assuntos
Indústria da Construção , Gerenciamento de Resíduos , Materiais de Construção , Meio Ambiente , Reciclagem/métodos , Gerenciamento de Resíduos/métodos
20.
J Chromatogr A ; 1676: 463263, 2022 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-35752152

RESUMO

To improve the efficiency of countercurrent chromatography (CCC) separations, we have previously proposed a new sample loading method called intermittent sample loading (ISL), in which continuous sample feed alternates with short periods of "clean" mobile phase feed to the CCC device. In semi-continuous separation processes, during sample feed periods, the sample is loaded in separate batches, each consisting of a series of intermittent sample loads. It was shown that the application of the intermittent sample loading method in the conventional isocratic CCC separations significantly increased process productivity and the concentration of compounds in the separated fractions. In this study, to further improve the CCC separations with intermittent sample loading, we discuss the application of the ISL method in the processes of close-loop recycling counter-current chromatography (CLR CCC). The advantage of the ISL CLR CCC over the ISL CCC is higher resolution and lower solvent consumption. Equations are presented that allow the simulation of periodic and semi-continuous ISL CLR CCC separations and the selection of optimal operational conditions for these separation processes. It is shown that the use of ISL technique in CLR CCC separations makes it possible to produce fractions of compounds with a much higher concentration than when using the conventional single sample loading method.


Assuntos
Distribuição Contracorrente , Modelos Teóricos , Simulação por Computador , Distribuição Contracorrente/métodos , Reciclagem , Solventes
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