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Cell-Phone Recycling by Solvolysis for Recovery of Metals

Journal of Materials Science and Chemical Engineering 2015年第1期3卷 52-57页

作者： Lorena Eugenia Sánchez Cadena zeferino gamino arroyo Mario Alberto González Lara Q.Demetrio Quiroz Departamento de Ingeniería Civil Universidad de GuanajuatoDIAv.Juárez 77CP 36000GuanajuatoGto.México Departamento de Ingeniería Química Universidad de GuanajuatoDCNyENoria Alta s/nCP 36050GuanajuatoGto.México

Mobile phones represent a significant and growing problem with respect to electrical waste and electronic equipment (WEEE). Nevertheless, they are perhaps one of the most valuable electronic products, since they are an important resource for the recovery of metals in terms of mass and volume. In this research a chemical recycling of mobile phones by solvolysis was investigated. The processing was performed by comminution in a hammer mill followed by screening to obtain mesh-4 sized flakes. Flakes were subjected to solvolysis. Different reaction conditions were tested. A reaction time between 2 - 7 hours and a temperature between 150°C - 300°C were the optimum conditions to dissolve the polymer contained in mobile phones. Metals were separated by filtration. Chemical analyses (ATR FT-IR, UV) were carried out on the solvent and the mobile phone flakes before and after solvolysis. A SEM study was carried out, before and after solvolysis, but only to the mobile phone flakes. Thermal transitions of mobile phone flakes were determined by DSC. Chemical results showed that some aromatic species migrate from mobile phones flakes to the solvent, due to the solvolysis reaction. Thermal analysis showed that the Tg, (glass transition temperature) of mobile phone flakes after solvolysis was different to Tg of the polymer before solvolysis, this is due to chemical changes in the molecule. A comparative SEM study revealed that, after solvolysis, the polymer contained in mobile phone flakes is more elastomeric. After solvolysis, solvent was recovered by means of a rotatory evaporator, so that it can be used again. The results obtained in this research showed that solvolysis is an alternative for metal recovery from mobile phones.

关键词： Cell-Phones Solvolysis Recycling

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Silver Recovery from Spent Silver Oxide Button Cell by Liquid-Liquid Extraction

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Journal of Materials Science and Chemical Engineering 2015年第7期3卷 148-153页

作者： zeferino gamino-arroyo Antonio Tapia-Cisneros Osvaldo M.Zamacona-Saucedo Irene Cano-Rodríguez Alberto F.Aguilera-Alvarado Lorena E.Sánchez-Cadena Fernando I.Gómez-Castro Departamento de Ingeniería Química Universidad de Guanajuato Guanajuato México Departamento de Ingeniería Civil Universidad de Guanajuato Guanajuato México

Button cell batteries are used in clocks, thermometers, remote controls, toys and other devices, and they are usually discarded in the trash once its useful life is over. Some models of these batteries contain silver oxide. In this paper we propose liquid-liquid extraction as separation process to recover the metal. First, silver determination is performed in different models of these batteries and leaching with nitric acid is carried out. Affinity study is done between several commercial extractants for silver. The best performing extractant is the bis(2-ethylhexyl) dithiophosphoric acid (D2EHDTPA). Furthermore, a study of the extraction yields as a function of extractant concentration and time is performed. The distribution isotherm is determined;complex extracted in organic phase and stripping conditions have been identified. With the aim of obtaining industrial application, a number of steps for a countercurrent process were defined by the McCabe-Thiele method. Finally, a study was done in micropilot scale. The results show that it is possible to recover silver from this type of waste.

关键词： Silver Spent Button Cells Leaching Recovery

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Analysis of the cryptocurrency market using different prototype-based clustering techniques

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Financial Innovation 2022年第1期8卷 141-186页

作者： Luis Lorenzo Javier arroyo Un iversidad Complute nse de Madrid Facultad de Estudios Estadisticos Madrid MadridSpain

Since the emergence of Bitcoin,cryptocurrencies have grown significantly,not only in terms of capitalization but also in ***,the cryptocurrency market can be a conducive arena for investors,as it offers many ***,it is difficult to *** study aims to describe,summarize,and segment the main trends of the entire cryptocurrency market in 2018,using data analysis ***-ingly,we propose a new clustering-based methodology that provides complementary views of the financial behavior of cryptocurrencies,and one that looks for associations between the clustering results,and other factors that are not involved in ***,the methodology involves applying three different partitional clustering algorithms,where each of them use a different representation for cryptocurrencies,namely,yearly mean,and standard deviation of the returns,distribution of returns that have not been applied to financial markets previously,and the time series of *** each representation provides a different outlook of the market,we also examine the integration of the three clustering results,to obtain a fine-grained analysis of the main trends of the *** conclusion,we analyze the association of the clustering results with other descriptive features of cryptocurrencies,including the age,technological attributes,and financial ratios derived from *** will help to enhance the profiling of the clusters with additional descriptive insights,and to find associations with other ***,this study describes the whole market based on graphical information,and a scalable methodology that can be reproduced by investors who want to understand the main trends in the market quickly,and those that look for cryptocurrencies with different financial *** our analysis of the 2018 and 2019 for extended period,we found that the market can be typically segmented in few clusters(five or less),and even considering the

关键词： Fintech Unsupervised machine learning Cryptocurrency Electronic market Clustering Investment portfolios

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Online risk‑based portfolio allocation on subsets of crypto assets applying a prototype‑based clustering algorithm

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Financial Innovation 2023年第1期9卷 797-836页

作者： Luis Lorenzo Javier arroyo Faculty of Statistic Studies Complutense UniversityAvda.Puerta de Hierros/n28040 MadridSpain

Mean-variance portfolio optimization models are sensitive to uncertainty in risk-return estimates,which may result in poor out-of-sample *** particular,the estimates may suffer when the number of assets considered is high and the length of the return time series is not sufficiently *** is precisely the case in the cryptocur-rency market,where there are hundreds of crypto assets that have been traded for a few *** propose enhancing the mean-variance(MV)model with a pre-selection stage that uses a prototype-based clustering algorithm to reduce the number of crypto assets considered at each investment *** the pre-selection stage,we run a prototype-based clustering algorithm where the assets are described by variables representing the profit-risk *** prototypes of the clustering partition are auto-matically examined and the one that best suits our risk-aversion preference is *** then run the MV portfolio optimization with the crypto assets of the selected *** proposed approach is tested for a period of 17 months in the whole cryp-tocurrency market and two selections of the cryptocurrencies with the higher market capitalization(175 and 250 cryptos).We compare the results against three methods applied to the whole market:classic MV,risk parity,and hierarchical risk parity *** also compare our results with those from investing in the market index *** simulation results generally favor our proposal in terms of profit and risk-profit financial *** result reaffirms the convenience of using machine learning methods to guide financial investments in complex and highly-volatile environments such as the cryptocurrency market.

关键词： Fintech Mean-variance Cryptocurrency Electronic market Portfolio allocation model Clustering

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Litter buffet:On the use of trash bins by birds in six boreal urban settlements

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Avian Research 2023年第2期14卷 182-190页

作者： Michelle García-arroyo Miguel A.Gomez-Martínez Ian MacGregor-Fors Ecosystems and Environment Research Programme Faculty of Biological and Environmental SciencesUniversity of HelsinkiNiemenkatu 73Lahti15140Finland Instituto de Biotecnología y Ecología Aplicada(INBIOTECA) Universidad VeracruzanaXalapa91090Mexico

Unintentional food resources in urban areas(street litter,food leftovers,overflowing trash bins)are dietary components of some urban-exploiter bird *** this study,we report on 13 bird species in six southern Finnish cities using urban trash bins and describe differences in their activity when provided with food resources(i.e.,bait)in different bin *** used generalized linear models(GLM)and classification and regression trees(CART)to test for associations between environmental variables and bird activity at the *** activity at the binscapes significantly differed among all cities and among types of bins and was significantly higher after placing bait in all *** with the largest opening had more activity as opposed to those with smaller openings or *** and gulls had the highest activity,with corvids usually being present before the bait was placed and gulls increasing their activity *** differences show that trash bin foraging is highly malleable and thus susceptible to management preventing its *** waste management measures could aid in reducing the number of species close to bins and their surroundings,benefiting both bird and human health.

关键词： Avian Behavior Binscape Food resources Urban ecology

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Apomorphine effects on the hippocampus

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Neural Regeneration Research 2018年第12期13卷 2064-2066页

作者： Luis Enrique arroyo-García Antonio Rodríguez-Moreno Gonzalo Flores Laboratorio de Neuropsiquiatria Instituto de Fisiologia Benemerita Universidad Autenoma de Puebla Puebla Mexico Laboratorio de Neurociencia Celular y Plasticidad Universidad Pablo de Olavide Sevilla Spain

Apomorphine is a non-specific dopamine receptor agonist that has been used in the treatment of some diseases and mental disorders. Its use has particularly well documented in Parkinson＇s disease（PD）. The dopaminergic agonists like apomorphine are related to oxidative processes that could induce cell damage and the functional impairment of some structures in the brain. However, most information about apomorphine in literature is focused on the improvement of the motor problems characteristic of PD, but little is known about the effects on cognitive behaviors and brain structures indirectly related to motor function. The presence of dopaminergic receptors in the hippocampus has recently been discovered, in connection with cognitive behaviors like learning and memory, these receptors are needed in neuronal plasticity. There has been a growing interest to know if this structure could be compromised by the effect of apomorphine and elucidate if part of the cognitive impairment present in the PD is due to the effect of apomorphine. In this mini-review, we summarized how apomorphine has been used since its creation, we discuss the latest information about its effect on the hippocampus and also the future perspectives to fully understand the effects of this compound.

关键词： dopamine receptor apomorphine hippocampus learning and memory plasticity dendritic length oxidative stress Parkinson's disease

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Impacts of fire severity and cattle grazing on early plant dynamics in old-growth Araucaria-Nothofagus forests

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Forest Ecosystems 2019年第4期6卷 298-311页

作者： Paola arroyo-Vargas Andres Fuentes-Ramírez Bart Muys Aníbal Pauchard Laboratorio de Biometría Departamento de Ciencias ForestalesUniversidad de La FronteraCasilla 54-DTemucoChile Programa de Magíster en Manejo de Recursos Naturales Facultad de Ciencias Agropecuarias y ForestalesUniversidad de La FronteraCasilla 54-DTemucoChile Butamallin Research Center for Global Change Universidad de La FronteraTemucoChile Instituto de Ecología y Biodiversidad(IEB) SantiagoChile Department of Earth and Environmental Sciences University of LeuvenCelestijnenlaan 200EBox 24113001 LeuvenBelgium Laboratorio de Invasiones Biológicas(LIB) Facultad de Ciencias ForestalesUniversidad de ConcepciónCasilla 160-CConcepciónChile.

Background: Fire has historically shaped the dynamics of Araucaria araucana-Nothofagus pumilio forests in the Andean region of South America. Nevertheless, human disturbances and stronger drought events have resulted in increased occurrence and severity of wildfires. Regardless of their conservation relevance, the initial response to fire of Araucaria-Nothofagus forests has not been well documented. Through this research we tested the hypothesis that plant composition of Araucaria-Nothofagus forest after fire will initially differ in its recovery depending on fire severity, but over time, plant similarity will increase among areas with different levels of fire severity. The study was carried out in old-growth Araucaria-Nothofagus forests in south-central Chile(38°S) that were burned in 2015. We studied vegetation response to three levels of fire severity(low(LS), moderate(MS) and high(HS) severity), also including an adjacent unburned forest(UN), which were assessed one, two and three years after fire. We also evaluated the impact of cattle on plant recovery after fire. We measured species richness, abundance, plant diversity and origin of all vascular plant ***: Species richness and plant abundance responded differently to fire severity. Time-since-fire had a significant effect on plant richness and abundance. Plant composition within LS areas was similar to UN areas, but MS and HS areas were significantly less diverse compared to UN and LS. In absence of other major disturbances, similarity in plant composition tended to increase over time across the different levels of fire severity, becoming more similar to UN. We also found a synergetic effect of cattle and fire on species richness. This interaction promotes the establishment of nonnative species and limits the recovery of native species following ***: Fire severity had a significant impact on the plant community of old-growth Araucaria-Nothofagus forests,especially in areas of high fir

关键词： Fire severity gradient Wildfire Post-fire plant recovery Cattle exclusion Synergistic effects of disturbances Araucaria araucana Nothofagus pumilio

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Geotechnical particle finite element method for modeling of soilstructure interaction under large deformation conditions

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第3期14卷 967-983页

作者： Josep Maria Carbonell Lluís Monforte Matteo O.Ciantia Marcos arroyo Antonio Gens MECAMAT Group Department of EngineeringFaculty of Science and TechnologyUniversitat de Vic-Universitat Central de Catalunya(UVic-UCC)VicSpain Centre Internacional de Mètodes Numèrics a l'Enginyeria(CIMNE) BarcelonaSpain School of Science and Engineering University of DundeeDundeeUK Universitat Politècnica de Cataluna-BarcelonaTech BarcelonaSpain

The possibilities of the particle finite element method(PFEM)for modeling geotechnical problems are increasingly *** is a numerical approach to solve large displacement and large strain continuum problems that are beyond the capabilities of classical finite element method(FEM).In PFEM,the computational domain is reconfigured for optimal solution by frequent remeshing and boundary *** inherits many concepts,such as a Lagrangian description of continuum,from classic geomechanical *** familiarity with more popular numerical methods facilitates learning and *** work focuses on G-PFEM,a code specifically developed for the use of PFEM in geotechnical *** article has two *** first is to give the reader an overview of the capabilities and main features of the current version of the G-PFEM and the second is to illustrate some of the newer developments of the code.G-PFEM can solve coupled hydro-mechanical static and dynamic problems involving the interaction of solid and/or deformable *** constitutive models for geomaterials are available,including features,such as structure and destructuration,which result in brittle *** solutions are robust,solidly underpinned by numerical technology including mixedfield formulations,robust and mesh-independent integration of elastoplastic constitutive models and a rigorous and flexible treatment of contact *** novel features presented in this work include the contact domain technique,a natural way to capture contact interactions and impose contact constraints between different continuum bodies,as well as a new simplified formulation for dynamic impact *** code performance is showcased by the simulation of several soil-structure interaction problems selected to highlight the novel code features:a rigid footing insertion in soft rock,pipeline insertion and subsequent lateral displacement on over-consolidated clay,screw-pile pull-out and the dyn

关键词： Particle finite element method(PFEM) Structured soils Nonlocal elastoplasticity Contact domain method Soil penetration problems

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Evaluation of New Graduate Nursing Orientation Program

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Open Journal of Nursing 2024年第8期14卷 433-446页

作者： Elizabeth arroyo Department of Education Capella University Minneapolis USA

The study site is a holistic patient-centered organization that has developed a 16-week long orientation program for new graduate nurses entering the hospital setting. The purpose of the program is for new graduate nurses to gain the confidence, competence, and critical thinking skills for providing safe patient care. The issue occurring within the organization is that there is an increasing rise in the number of turnover rates of new graduates leaving the hospital, thus making evaluating the program a necessity to problem-solving. There has been no evaluation of the program in the past five years to reveal why the increase in the recent turnover rates. The data collected during the interview process was coded and categorized into three main sections: organizational, substantive, and theoretical. The evaluator used an organizational category to investigate for board areas or issues within the problem attempting to be solved. The evaluator concluded from the results and findings that the issue, a poor preceptor-preceptee relationship was seen by all stakeholders involved. The literature presented concludes that continuous evaluation of orientation programs is crucial for the professional and personal growth of new graduate nurses in the hospital.

关键词： New Graduate Nurses Preceptors Turnover Orientation

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Association of residual feed intake with abundance of ruminal bacteria and biopolymer hydrolyzing enzyme activities during the peripartal period and early lactation in Holstein dairy cows

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Journal of Animal Science and Biotechnology 2018年第3期9卷 717-726页

作者： Ahmed A.Elolimy José M.arroyo FernANDa Batistel Michael A.Iakiviak Juan J.Loor Mammalian Nutri Physio Genomics Department of Animal SciencesUniversity of Illinois Department of Animal Sciences University of Illinois Departamento de Nutrición Animal Instituto de Producción Animal Facultad de Veterinaria Universidad de la Republica Division of Nutritional Sciences Illinois Informatics Institute University of Illinois

Background: Residual feed intake(RFI) in dairy cattle typically calculated at peak lactation is a measure of feed efficiency independent of milk production level. The objective of this study was to evaluate differences in ruminal bacteria, biopolymer hydrolyzing enzyme activities, and overall performance between the most-and the leastefficient dairy cows during the peripartal period. Twenty multiparous Holstein dairy cows with daily ad libitum access to a total mixed ration from d-10 to d 60 relative to the calving date were used. Cows were classified into most-efficient(i.e. with low RFI, n = 10) and least-efficient(i.e. with high RFI, n = 10) based on a linear regression model involving dry matter intake(DMI), fat-corrected milk(FCM), changes in body weight(BW), and metabolic ***: The most-efficient cows had ~ 2.6 kg/d lower DMI at wk 4, 6, 7, and 8 compared with the least-efficient cows. In addition, the most-efficient cows had greater relative abundance of total ruminal bacterial community during the peripartal period. Compared with the least-efficient cows, the most-efficient cows had 4-fold greater relative abundance of Succinivibrio dextrinosolvens at d-10 and d 10 around parturition and tended to have greater abundance of Fibrobacter succinogenes and Megaspheara elsdenii. In contrast, the relative abundance of Butyrivibrio proteoclasticus and Streptococcus bovis was lower and Succinimonas amylolytica and Prevotella bryantii tended to be lower in the most-efficient cows around calving. During the peripartal period, the most-efficient cows had lower enzymatic activities of cellulase, amylase, and protease compared with the least-efficient ***: The results suggest that shifts in ruminal bacteria and digestive enzyme activities during the peripartal period could, at least in part, be part of the mechanism associated with better feed efficiency in dairy cows.

关键词： Dairy cows Enzyme activity Peripartal period RFI Rumen bacteria

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