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1.
J. optom. (Internet) ; 17(1)Jan.-March. 2024. tab, graf
Artigo em Inglês | IBECS | ID: ibc-229119

RESUMO

Purpose This review aimed to estimate the prevalence of computer vision syndrome (CVS) in the general population and subgroups. Methods A search was conducted in the following the databases: PubMed, SCOPUS, EMBASE, and Web of Science until February 13, 2023. We included studies that assessed the prevalence of CVS in any population. The Joanna Briggs Institute's critical appraisal tool was used to evaluate the methodological quality. A meta-analysis of the prevalence of CVS was done using a random-effects model, assessing the sources of heterogeneity using subgroup and meta-regression analyses. Results A total of 103 cross-sectional studies with 66 577 participants were included. The prevalence of CVS was 69.0% (95% CI: 62.3 to 75.3; I2: 99.7%), ranging from 12.1 to 97.3% across studies. Point prevalence was higher in women than in men (71.4 vs. 61.8%), university students (76.1%), Africa (71.2%), Asia (69.9%), contact lens wearers (73.1% vs. 63.8%) in studies conducted before the COVID-19 pandemic (72.8%), and in those that did not use the CVS-Q questionnaire (75.4%). In meta-regression, using the CVS-Q scale was associated with a lower prevalence of CVS. Conclusion Seven out of ten people suffer from CVS. Preventive strategies and interventions are needed to decrease the prevalence of this condition which can affect productivity and quality of life. Future studies should standardize a definition of CVS. (AU)


Assuntos
Prevalência , Transtornos da Visão , Saúde Ocupacional , Equipamentos e Provisões Elétricas
3.
Artigo em Inglês | MEDLINE | ID: mdl-36834193

RESUMO

Due to the popularization and development of new energy vehicles (NEVs) worldwide, power batteries that have been used are being retired and replaced. In China's battery recycling industry, the legal NEV battery recycling enterprises are at a negative financial performance. Based on theory of organizational adaptation, the key to innovation performance and sustainable development is recognition of the environment and strengthening organizational flexibility. This study empirically explores the bidirectional dynamic relationships among heterogeneous environmental uncertainties, innovation activities, firm growth and strategic flexibility in Chinese NEV battery recycling firms. A total of 1040 sample data were collected from 2015 to 2021. The research results demonstrate that environmental uncertainty (EU), strategic flexibility (SF) and innovation activities (INNO) all had impacts on firm growth (FG). Specifically, INNO had strongly negative effects in the short term, and in the long term, it will bring a positive effect to FG; the impact of EPU was more important than market uncertainty (MU) to FG and innovation activities. This could be due to the dependence of the Chinese NEV battery recycling industry on government policy. However, MU has a strong impact on SF. Moreover, the levels of SF should be reasonable, otherwise it could be a burden to enterprises. There also exists the bidirectional dynamic relationships between FG and INNO. This study contributes a non-core perspective to strategic flexibility research by revealing the complex environmental mechanism, and to the Chinese NEV battery recycling industry we provide a theoretical basis and practical guidance for government and firms on how to apply SF to promote innovation and realize growth in the present business environment.


Assuntos
Inovação Organizacional , Reciclagem , Humanos , China , Comércio , Incerteza , Equipamentos e Provisões Elétricas
4.
j. public health epidemiol. (jphe) ; 15(2): 173-182, 2023. tables
Artigo em Inglês | AIM (África) | ID: biblio-1427896

RESUMO

Studies on waste management in Côte d'Ivoire are mostly focused on household and solid waste. It is appropriate to take a sustained look at the management of electrical and electronic equipment waste to better guide policies in this area. This work is a cross-sectional study covering the period from April 1, 2022 to June 30, 2022. The aim was to determine the knowledge and practices of the independent electrical and electronic repairers of the city of Bouaké in terms of electrical and electronic equipment waste (WEEE) management. A comprehensive sample of 307 people was interviewed by means of a questionnaire. The repairers interviewed had already heard of WEEE in 47.2% of cases. They had a good level of knowledge of WEEE in 85.5% of cases. In the final model in multivariate analysis, only the possession of a radio set at home had a significant influence on knowledge of WEEE. Repairers were unaware of the existence of D3E management legislation in 60.7% of cases; apart from humans (84.8%) who were most exposed to the dangers of inappropriate management of WEEE, other entities (air, soil, water, animals) would be polluted according to 36.6, 35.2, 4.1, and 3.4% of repairers, respectively. The most feared type of harm reported is injury (95.65%). Subjects dumped WEEE in a municipal landfill in 32.4% of cases. Sale, empowerment of pre-collection agents, and handing over to a recycling professional, cumulatively represent the most common practice (66.9%).


Assuntos
Equipamentos e Provisões Elétricas , Fenômenos Ecológicos e Ambientais , Estudos Transversais , Reutilização de Equipamento , Conhecimento , ISO 14000 , Trabalho Doméstico
5.
J Appl Clin Med Phys ; 23(12): e13822, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36356260

RESUMO

PURPOSE: The aim of this work was to evaluate the SunCHECK PerFRACTION, the software for in vivo monitoring using EPID images. MATERIALS/METHODS: First, the PerFRACTION ability to detect errors was investigated simulating two situations: (1) variation of LINAC output and (2) variation of the phantom thickness. An ionization chamber was used as reference to measure the introduced dose variations. Both tests used EPID in integrated mode (absolute dose). Second, EPID measurements in integrated mode were carried out during an independent Brazilian governmental audit that provided four phantoms and TLDs. PerFRACTION calculated the absolute dose on EPID plane, and it compared with predicted calculated dose for every delivered plan. The dose deviations reported using PerFRACTION were compared with dose deviations reported by the independent audit. Third, an end-to-end test using a heterogeneous phantom was performed. A VMAT plan with EPID in cine mode was delivered. PerFRACTION calculated the mean dose on CBCT using EPID information and log files. The calculated doses at four different points were compared with ionization chambers measurements. RESULTS: About the first test, the largest difference found was 1.2%. Considering the audit results, the variations detected by TLD measurements and by PerFRACTION dose calculation on EPID plane were close: 12 points had variations less than 2%, 2 points with variation between 2% and 3%, and 2 points with deviations greater than 3% (max 3.7%). The end-to-end tests using a heterogeneous phantom achieved dose deviation less than 1.0% in the water-equivalent region. In the mimicking lung region, the deviations were higher (max 7.3%), but in accordance with what is expected for complex situations. CONCLUSION: The tests results indicate that PerFRACTION dose calculations in different situations have good agreement with standard measurements. Action levels were suggested for absolute dose on EPID plane as well as 3D dose calculation on CBCT using PerFRACTION.


Assuntos
Equipamentos e Provisões Elétricas , Radioterapia de Intensidade Modulada , Humanos , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Software , Imagens de Fantasmas , Radiometria/métodos
6.
J Appl Clin Med Phys ; 23(10): e13786, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36121120

RESUMO

PURPOSE: Varian provides a DICOM RT Plan file that users can deliver to the electronic portal imaging device (EPID) panel to confirm the linear accelerator delivers consistent dose output across several regions of interest for varying dose rates and gantry speeds (DRGS). This work investigates if (a) the vendor-provided DRGS DICOM RT Plan is valid within the gantry speed range of stereotactic body radiation therapy (SBRT) treatments, and (b) if output constancy is maintained at those gantry speeds on a TrueBeam. METHODS: Python code was written to iterate through all control points in the DICOM RT Plan files for 21 SBRT patients and the MU per degree values were calculated for each control point. A histogram was generated to illustrate how MU per degree was distributed among the control points from the patient plans. Then, the total number of MUs was increased in the vendor-provided DRGS DICOM file to make a "modified DRGS DICOM RT Plan," which surpasses the maximum MU per degree value found in the patient plans, forcing the gantry to travel at slow speeds and deliver more MU per degree over the same arc length (representative of those during SBRT treatment delivery). The modified DRGS DICOM RT Plan file was then delivered on a TrueBeam to acquire EPID images of the dose distribution. The EPID images were analyzed with Pylinac, a Python library that analyzes DICOM RT images acquired during routine linac QA. RESULTS: Over 83% of patient DICOM RT Plan control points had MU per degree values greater than the MU per degree values in the vendor-provided DRGS DICOM file. The Pylinac analysis of the EPID-acquired images found a maximum deviation of 0.4% from machine baselines. CONCLUSIONS: The modified DRGS DICOM file can be used to determine if a TrueBeam linac is operating within specifications even when very low gantry speeds are reached.


Assuntos
Equipamentos e Provisões Elétricas , Radioterapia de Intensidade Modulada , Humanos , Aceleradores de Partículas , Planejamento da Radioterapia Assistida por Computador/métodos , Dosagem Radioterapêutica
7.
J Appl Clin Med Phys ; 23(8): e13699, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35856943

RESUMO

PURPOSE: Well-designed routine multileaf collimator (MLC) quality assurance (QA) is important to assure external-beam radiation treatment delivery accuracy. This study evaluates the clinical necessity of a comprehensive weekly (C-Weekly) MLC QA program compared to the American Association of Physics in Medicinerecommended weekly picket fence test (PF-Weekly), based on our seven-year experience with weekly MLC QA. METHODS: The C-Weekly MLC QA program used in this study includes 5 tests to analyze: (1) absolute MLC leaf position; (2) interdigitation MLC leaf position; (3) picket fence MLC leaf positions at static gantry angle; (4) minimum leaf-gap setting; and (5) volumetric-modulated arc therapy delivery. A total of 20,226 QA images from 16,855 tests (3,371 tests × 5) for 11 linacs at 5 photon clinical sites from May 2014 to June 2021 were analyzed. Failure mode and effects analysis was performed with 5 failure modes related to the 5 tests. For each failure mode, a risk probability number (RPN) was calculated for a C-Weekly and a PF-Weekly MLC QA program. The probability of occurrence was evaluated from statistical analyses of the C-Weekly MLC QA. RESULTS: The total number of failures for these 16,855 tests was 143 (0.9%): 39 (27.3%) for absolute MLC leaf position, 13 (9.1%) for interdigitation position, 9 (6.3%) for static gantry picket fence, 2 (1.4%) for minimum leaf-gap setting, and 80 (55.9%) for VMAT delivery. RPN scores for PF-Weekly MLC QA ranged from 60 to 192 and from 48 to 96 for C-Weekly MLC QA. CONCLUSION: RPNs for the 5 failure modes of MLC QA tests were quantitatively determined and analyzed. A comprehensive weekly MLC QA is imperative to lower the RPNs of the 5 failure modes to the desired level (<125); those from the PF-Weekly MLC QA program were found to be higher (>125). This supports the clinical necessity for comprehensive weekly MLC QA.


Assuntos
Aceleradores de Partículas , Radioterapia de Intensidade Modulada , Equipamentos e Provisões Elétricas , Humanos , Radioterapia de Intensidade Modulada/métodos
8.
J Appl Clin Med Phys ; 23(7): e13661, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35666629

RESUMO

For Elekta Agility linear accelerators, the iViewGT electronic portal imaging device (EPID) is positioned at a nominal X-Ray source-to-panel distance of 1600 mm. For display, image registration, and data processing purposes, the image pixels are scaled to spatial units at the treatment isocenter plane. This is achieved by applying a pixel scaling factor (PSF). During this investigation, the dependence of the PSF at cardinal gantry angles was determined along with the resulting effects on the multi-leaf collimator (MLC) quality assurance (QA) results for three linear accelerators (linacs). The PSF was found to vary by 0.0018-0.0022 mm/pixel during gantry rotation, which resulted in variations in the mean MLC reported error of up to 0.8 mm at 100 mm off-axis with the gantry rotated to 180°. Measurement and application of a gantry angle-specific PSF is a simple process that can be implemented to improve the accuracy of EPID-based MLC QA at cardinal gantry angles.


Assuntos
Equipamentos e Provisões Elétricas , Aceleradores de Partículas , Eletrônica , Humanos , Imagens de Fantasmas , Rotação
9.
J Appl Clin Med Phys ; 23(9): e13660, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35678793

RESUMO

PURPOSE: Multi-leaf-collimator (MLC) leaf position accuracy is important for accurate dynamic radiotherapy treatment plan delivery. Machine log files have become widely utilized for quality assurance (QA) of such dynamic treatments. The primary aim is to test the sensitivity of machine log files in comparison to electronic portal imaging device (EPID)-based measurements to MLC position errors caused by leaf backlash. The secondary aim is to investigate the effect of MLC leaf backlash on MLC leaf motion during clinical dynamic plan delivery. METHODS: The sensitivity of machine log files and two EPID-based measurements were assessed via a controlled experiment, whereby the length of the "T" section of a series of 12 MLC leaf T-nuts in a Varian Millennium MLC for a Trilogy C-series type linac was reduced by sandpapering the top of the "T" to introduce backlash. The built-in machine MLC leaf backlash test as well as measurements for two EPID-based dynamic MLC positional tests along with log files were recorded pre- and post-T-nut modification. All methods were investigated for sensitivity to the T-nut change by assessing the effect on measured MLC leaf positions. A reduced version of the experiment was repeated on a TrueBeam type linac with Millennium MLC. RESULTS: No significant differences before and after T-nut modification were detected in any of the log file data. Both EPID methods demonstrated sensitivity to the introduced change at approximately the expected magnitude with a strong dependence observed with gantry angle. EPID-based data showed MLC positional error in agreement with the micrometer measured T-nut length change to 0.07 ± 0.05 mm (1 SD) using the departmental routine QA test. Backlash results were consistent between linac types. CONCLUSION: Machine log files appear insensitive to MLC position errors caused by MLC leaf backlash introduced via the T-nut. The effect of backlash on clinical MLC motions is heavily gantry angle dependent.


Assuntos
Radioterapia de Intensidade Modulada , Equipamentos e Provisões Elétricas , Humanos , Aceleradores de Partículas , Imagens de Fantasmas , Folhas de Planta , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos
10.
Phys Med Biol ; 67(15)2022 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-35767982

RESUMO

Objective.Transitin vivodosimetry methods monitor that the dose distribution is delivered as planned. However, they have a limited ability to identify and to quantify the cause of a given disagreement, especially those caused by position errors. This paper describes a proof of concept of a simplein vivotechnique to infer a position error from a transit portal image (TPI).Approach.For a given treatment field, the impact of a position error is modeled as a perturbation of the corresponding reference (unperturbed) TPI. The perturbation model determines the patient translation, described by a shift vector, by comparing a givenin vivoTPI to the corresponding reference TPI. Patient rotations can also be determined by applying this formalism to independent regions of interest over the patient. Eight treatment plans have been delivered to an anthropomorphic phantom under a large set of couch shifts (<15 mm) and rotations (<10°) to experimentally validate this technique, which we have named Transit-Guided Radiation Therapy (TGRT).Main results.The root mean squared error (RMSE) between the determined and the true shift magnitudes was 1.0/2.4/4.9 mm for true shifts ranging between 0-5/5-10/10-15 mm, respectively. The angular accuracy of the determined shift directions was 12° ± 14°. The RMSE between the determined and the true rotations was 0.5°. The TGRT technique decoupled translations and rotations satisfactorily. In 96% of the cases, the TGRT technique decreased the existing position error. The detection threshold of the TGRT technique was around 1 mm and it was nearly independent of the tumor site, delivery technique, beam energy or patient thickness.Significance.TGRT is a promising technique that not only provides reliable determinations of the position errors without increasing the required equipment, acquisition time or patient dose, but it also adds on-line correction capabilities to existing methods currently using TPIs.


Assuntos
Equipamentos e Provisões Elétricas , Planejamento da Radioterapia Assistida por Computador , Humanos , Imagens de Fantasmas , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos
11.
Stud Health Technol Inform ; 294: 571-572, 2022 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-35612149

RESUMO

Omaolo© electronic symptom checkers (ESCs) have been developed to make triage for primary health care patients in Finland. Based on the analysis of the patient's responses to a set of questions, the ESC classifies him/her as emergent, urgent, not urgent, or advices on self-care. In this study the user answered the questions posed by the electronic symptom checker, after which a nurse assessed the urgency of the same user's symptom. The triage nurse was not allowed to know the result of the electronic symptom assessment until he or she had assessed the patient's condition. The level of triage was compared between ESC and nurse in each individual case. Findings from 825 individual cases were analyzed. The mean "exactly matched" for all symptom estimates was 52.6%. The mean "exactly matched" or "overconservative but suitable" for all symptom assessments was 66.6%. Safe assessments of electronic symptom checkers accounted for 98.6% of all assessments. A case was defined as "safe" if the recommendation for action given by the symptom assessment was at most one level less urgent than the nurse's triage assessment of the same case. The findings show that electronic symptom assessments are safe compared to the assessment of an experienced nurse.


Assuntos
Equipamentos e Provisões Elétricas/normas , Enfermeiras e Enfermeiros/normas , Atenção Primária à Saúde/métodos , Avaliação de Sintomas/instrumentação , Avaliação de Sintomas/métodos , Triagem/métodos , Eletrônica , Feminino , Finlândia , Humanos , Masculino , Atenção Primária à Saúde/normas , Avaliação de Sintomas/normas , Triagem/normas
12.
J Appl Clin Med Phys ; 23(7): e13618, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35570379

RESUMO

Intensity modulation treatments are widely used in radiotherapy because of many known advantages. In this context, the picket fence test (PF) is a relevant test to check the Multileaf Collimator (MLC) performances. So this work compares and evaluates three analysis platforms for the PF used routinely by three different institutions. This study covers two linear accelerators (Linac) with two MLC types, a Millenium 120 MLC and Millenium 120 High Definition MLC respectively on a Varian Truebeam and Truebeam STx. Both linacs include an As 1200 portal imager (EPID). From a reference PF plan, MLC errors have been introduced to modify the slits in position or width (shifts from 0.1 to 0.5 mm on one or both banks). Then errors have been defined on the EPID to investigate detection system deviations (signal sensitivity and position variations). Finally, 110 DICOM-RT images have been generated and analyzed by each software system. All software systems have shown good performances to quantify the position errors, even though the leaf pair identifications can be wrong in some cases regarding the analysis method considered. The slit width measurement (not calculated by all software systems) has shown good sensitivity, but some quantification difficulties have been highlighted regardless of the analysis method used. Linked to the expected accuracy of the PF test, the imager variations have demonstrated considerable influence in the results. Differences in the results and the analysis methods have been pointed out for each software system. The results can be helpful to optimize the settings of each analysis software system depending on expectations and treatment modalities of each institution.


Assuntos
Radioterapia (Especialidade) , Radioterapia de Intensidade Modulada , Equipamentos e Provisões Elétricas , Humanos , Aceleradores de Partículas , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada/métodos , Software
13.
São Paulo; s.n; 2022. 147 p.
Tese em Português | LILACS | ID: biblio-1437596

RESUMO

A produção de Equipamentos Elétricos e Eletrônicos (EEE) tem crescido anualmente e juntamente com ela a geração de Resíduo de Equipamentos Elétricos e Eletrônicos (REEE). A alta complexidade na fabricação dos EEE juntamente com o uso de diferentes materiais torna particularmente difícil a logística reversa dos resíduos gerados. A Política Nacional de Resíduos Sólidos, marco regulatório da gestão de resíduos sólidos no Brasil, estabelece como hierarquia de resíduos: a não geração, redução, reutilização e reciclagem. Uma das estratégias para a redução dos REEE é o uso dos equipamentos até o final de sua vida útil. A estratégia sugerida neste trabalho é o Reparo dos EEE, podendo assim estender seu uso, prolongando sua vida útil e retardando a necessidade do consumo de novo produto similar, contribuindo assim com a minimização da geração de REEE. Essa pesquisa tem o objetivo de analisar a atividade de Reparo como estratégia para reduzir o descarte de resíduos de equipamentos elétricos e eletrônicos pelo mundo, em contraponto com a realidade brasileira. O trabalho desenvolvido em quatro etapas: i) Revisão bibliográfica sistemática sobre Reparo de EEE/REEE; ii) Identificação do posicionamento do Reparo nos processos de valorização de REEE no mundo, com base em revisão bibliográfica; iii) Entrevista com atores da cadeia e análise temática, com base em análise do discurso; e iv) Elaboração de produto técnico-tecnológico para divulgação e incentivo do Reparo de EEE. Os resultados envolvem: i) o estado da arte da atividade de Reparo do REEE, no Brasil e no mundo; ii) conceituação de termos relacionados ao Reparo; iii) interação, barreiras e facilitadores da cadeira de atores do Reparo de EEE como um dos processos de valorização de REEE no Brasil; iv) manual para implantação de evento para divulgação e discussão da atividade de Reparo de EEE como estratégia de minimização de REEE para a sociedade em geral.


The production of Electrical and Electronic Equipment (EEE) has grown annually and along with it the generation of Waste Electrical and Electronic Equipment (WEEE). The high complexity in the manufacturing of EEE along with the use of different materials makes the reverse logistics of the generated waste particularly difficult. The National Policy for Solid Waste, the regulatory framework for solid waste management in Brazil, establishes as waste hierarchy: non-generation, reduction, reuse and recycling. One of the strategies for the reduction of WEEE is the use of equipment until the end of its useful life. The strategy suggested in this work is the repair of EEE, which can extend its use, prolonging its useful life and delaying the need for consumption of a new similar product, thus contributing to the minimization of WEEE generation. This research aims to analyze the Repair activity as a strategy to reduce the disposal of waste electrical and electronic equipment around the world, in contrast with the Brazilian reality. The work is developed in four stages: i) Systematic bibliographic review on Repair of EEE/ WEEE; ii) Identification of the position of the Repair in the processes of valorization of WEEE in the world, based on bibliographic review; iii) Interview with actors of the chain and thematic analysis, based on discourse analysis; and iv) Preparation of a technical-technological product for dissemination and encouragement of EEE Repair. The results involve: i) the state of the art of the EEE Repair activity in Brazil and in the world; ii) conceptualization of terms related to the Repair; iii) interaction, barriers and facilitators of the EEE Repair chain actors as one of the WEEE valorization processes in Brazil; iv) manual for the implementation of an event for the dissemination and discussion of the EEE Repair activity as a WEEE minimization strategy for society in general.


Assuntos
Equipamentos e Provisões Elétricas , Resíduo Eletrônico
14.
Int J Mol Sci ; 22(21)2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34768976

RESUMO

Current agricultural practices are not sustainable; however, the non-thermal plasma treatment of seeds may be an eco-friendly alternative to alter macroscopic plant growth parameters. Despite numerous successful results of plasma-seed treatments reported in the literature, the plasma-treatment parameters required to improve plant growth remain elusive due to the plethora of physical, chemical, and biological variables. In this study, we investigate the optimal conditions in our surface dielectric barrier discharge (SDBD) setup, using a parametric study, and attempt to understand relevant species in the plasma treatment using in situ Fourier transform infrared (FTIR) absorption spectroscopy. Our results suggest that treatment time and voltage are key parameters for accelerated germination; however, no clear conclusion on causative agents can be drawn.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Gases em Plasma/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Equipamentos e Provisões Elétricas , Germinação/fisiologia , Gases em Plasma/administração & dosagem , Gases em Plasma/química , Espécies Reativas de Nitrogênio/administração & dosagem , Espécies Reativas de Oxigênio/administração & dosagem , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de Tempo
15.
Nature ; 597(7877): 503-510, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34552257

RESUMO

Large, distributed collections of miniaturized, wireless electronic devices1,2 may form the basis of future systems for environmental monitoring3, population surveillance4, disease management5 and other applications that demand coverage over expansive spatial scales. Aerial schemes to distribute the components for such networks are required, and-inspired by wind-dispersed seeds6-we examined passive structures designed for controlled, unpowered flight across natural environments or city settings. Techniques in mechanically guided assembly of three-dimensional (3D) mesostructures7-9 provide access to miniature, 3D fliers optimized for such purposes, in processes that align with the most sophisticated production techniques for electronic, optoelectronic, microfluidic and microelectromechanical technologies. Here we demonstrate a range of 3D macro-, meso- and microscale fliers produced in this manner, including those that incorporate active electronic and colorimetric payloads. Analytical, computational and experimental studies of the aerodynamics of high-performance structures of this type establish a set of fundamental considerations in bio-inspired design, with a focus on 3D fliers that exhibit controlled rotational kinematics and low terminal velocities. An approach that represents these complex 3D structures as discrete numbers of blades captures the essential physics in simple, analytical scaling forms, validated by computational and experimental results. Battery-free, wireless devices and colorimetric sensors for environmental measurements provide simple examples of a wide spectrum of applications of these unusual concepts.


Assuntos
Biomimética , Equipamentos e Provisões Elétricas , Miniaturização/instrumentação , Sementes , Vento , Tecnologia sem Fio/instrumentação , Colorimetria , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Fenômenos Mecânicos , Microfluídica , Vigilância da População/métodos , Rotação
16.
PLoS One ; 16(9): e0256836, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34473780

RESUMO

The study is aimed at the frosting problem of the air source heat pump in the low temperature and high humidity environment, which reduces the service life of the system. First, the frosting characteristics at the evaporator side of the air source heat pump system are analyzed. Then, a new defrost technology is proposed, and dimensional theory and neural network are combined to predict the transfer performance of the new system. Finally, an adaptive network control algorithm is proposed to predict the frosting amount. This algorithm optimizes the traditional neural network algorithm control process, and it is more flexible, objective, and reliable in the selection of the hidden layer, the acquisition of the optimal function, and the selection of the corresponding learning rate. Through model performance, regression analysis, and heat transfer characteristics simulation, the effectiveness of this method is further confirmed. It is found that, the new air source heat pump defrost system can provide auxiliary heat, effectively regulating the temperature and humidity. The mean square error is 0.019827, and the heat pump can operate efficiently under frosting conditions. The defrost system is easy to operate, and facilitates manufactures designing for different regions under different conditions. This research provides reference for energy conservation, emission reduction, and sustainable economic development.


Assuntos
Simulação por Computador , Equipamentos e Provisões Elétricas , Congelamento/efeitos adversos , Calefação/instrumentação , Aprendizado de Máquina , Modelos Teóricos , Redes Neurais de Computação , Ar , Temperatura Alta , Umidade/efeitos adversos , Água/química
17.
Proc Natl Acad Sci U S A ; 118(34)2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34408019

RESUMO

Understanding how populations' daily behaviors change during the COVID-19 pandemic is critical to evaluating and adapting public health interventions. Here, we use residential electricity-consumption data to unravel behavioral changes within peoples' homes in this period. Based on smart energy-meter data from 10,246 households in Singapore, we find strong positive correlations between the progression of the pandemic in the city-state and the residential electricity consumption. In particular, we find that the daily new COVID-19 cases constitute the most dominant influencing factor on the electricity demand in the early stages of the pandemic, before a lockdown. However, this influence wanes once the lockdown is implemented, signifying that residents have settled into their new lifestyles under lockdown. These observations point to a proactive response from Singaporean residents-who increasingly stayed in or performed more activities at home during the evenings, despite there being no government mandates-a finding that surprisingly extends across all demographics. Overall, our study enables policymakers to close the loop by utilizing residential electricity usage as a measure of community response during unprecedented and disruptive events, such as a pandemic.


Assuntos
COVID-19/epidemiologia , COVID-19/prevenção & controle , Controle de Doenças Transmissíveis/métodos , Comportamento Cooperativo , Equipamentos e Provisões Elétricas/estatística & dados numéricos , Eletricidade , Quarentena , COVID-19/transmissão , Características da Família , Humanos , Saúde Pública , SARS-CoV-2/isolamento & purificação , Singapura/epidemiologia
18.
ACS Appl Mater Interfaces ; 13(25): 29780-29787, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34128631

RESUMO

To meet the increasing demand for wearable sensing devices, flexible supercapacitors (SCs) as energy storage devices play significant roles in powering sensors/biosensors for healthcare monitoring. Because of its high conductivity and remarkable specific capacitance in SCs, molybdenum nitride (MoN) has been widely used. Herein, a flexible helical structure of MoN modified on nitrogen-doped carbon cloth (CC@CN@MoN) has been prepared by a simple nitride process, delivering an ultralong cycle life of 10,000 cycles and high areal capacitance of 467.6 mF cm-2 as SCs. Moreover, the as-fabricated flexible all-solid-state asymmetrical SCs (ASCs) of CC@CN@MoN//CC@NiCo2O4 demonstrated outstanding electrochemical behavior after 10,000 cycles and over 90% retention, and the value of areal capacitance could reach 90.8 mF cm-2 at 10 mA cm-2. Integrated with solar energy, ASCs could be used as a self-powered energy system for strain sensors in detecting human movement, and finger movements could be further real-time monitored remotely via a smartphone. Prospectively, wearable helical MoN solid-state SCs for self-powered strain smartsensors would inspire the development of structured materials in the application of energy storage, portable self-powering, and strain or chemical/biochemical smartsensors.


Assuntos
Molibdênio/química , Monitorização Fisiológica/instrumentação , Dispositivos Eletrônicos Vestíveis , Equipamentos e Provisões Elétricas , Desenho de Equipamento , Humanos , Maleabilidade , Smartphone
19.
Nat Commun ; 12(1): 3167, 2021 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-34039966

RESUMO

Ubiquitous use of electronic devices has led to an unprecedented increase in related waste as well as the worldwide depletion of reserves of key chemical elements required in their manufacturing. The use of biodegradable and abundant organic (carbon-based) electronic materials can contribute to alleviate the environmental impact of the electronic industry. The pigment eumelanin is a bio-sourced candidate for environmentally benign (green) organic electronics. The biodegradation of eumelanin extracted from cuttlefish ink is studied both at 25 °C (mesophilic conditions) and 58 °C (thermophilic conditions) following ASTM D5338 and comparatively evaluated with the biodegradation of two synthetic organic electronic materials, namely copper (II) phthalocyanine (Cu-Pc) and polyphenylene sulfide (PPS). Eumelanin biodegradation reaches 4.1% (25 °C) in 97 days and 37% (58 °C) in 98 days, and residual material is found to be without phytotoxic effects. The two synthetic materials, Cu-Pc and PPS, do not biodegrade; Cu-Pc brings about the inhibition of microbial respiration in the compost. PPS appears to be potentially phytotoxic. Finally, some considerations regarding the biodegradation test as well as the disambiguation of "biodegradability" and "bioresorbability" are highlighted.


Assuntos
Biodegradação Ambiental , Equipamentos e Provisões Elétricas , Química Verde/métodos , Poluentes do Solo/química , Animais , Compostagem , Decapodiformes/química , Indóis/química , Lolium/efeitos dos fármacos , Lolium/crescimento & desenvolvimento , Melaninas/química , Melaninas/isolamento & purificação , Microbiota/efeitos dos fármacos , Compostos Organometálicos/química , Polímeros/química , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Microbiologia do Solo , Poluentes do Solo/toxicidade
20.
Nat Protoc ; 16(5): 2395-2417, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33846631

RESUMO

Numerous fields of science and technology, including healthcare, robotics and bioelectronics, have begun to switch their research direction from developing 'high-end, high-cost' tools towards 'high-end, low-cost' solutions. Graphene electronic tattoos (GETs), whose fabrication protocol is discussed in this work, are ideal building blocks of future wearable technology due to their outstanding electromechanical properties. The GETs are composed of high-quality, large-scale graphene that is transferred onto tattoo paper, resulting in an electronic device that is applied onto skin like a temporary tattoo. Here, we provide a comprehensive GET fabrication protocol, starting from graphene growth and ending with integration onto human skin. The methodology presented is unique since it utilizes high-quality electronic-grade graphene, while the processing is done by using low-cost and off-the-shelf methods, such as a mechanical cutter plotter. The GETs can be either used in combination with advanced scientific equipment to perform precision experiments, or with low-cost electrophysiology boards, to conduct similar operations from home. In this protocol, we showcase how GETs can be applied onto the human body and how they can be used to obtain a variety of biopotentials, including electroencephalogram (brain waves), electrocardiogram (heart activity), electromyogram (muscle activity), as well as monitoring of body temperature and hydration. With graphene available from commercial sources, the whole protocol consumes ~3 h of labor and does not require highly trained personnel. The protocol described in this work can be readily replicated in simple laboratories, including high school facilities.


Assuntos
Equipamentos e Provisões Elétricas , Grafite/química , Tatuagem/instrumentação , Desenho de Equipamento , Fenômenos Mecânicos
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