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1.
Big Data ; 11(1): 1-17, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36787408

RESUMO

Chronic fatigue symptoms of jobs are risk factors that may cause errors and lead to occupational accidents. For instance, occupational injuries and traffic accidents stem from overlooking long-term fatigue. According to statistics for fatigue driving, it was found that fatigue driving is one of the main causes of traffic accidents. The resulting decrease in the quality of traffic, as well as impaired traffic flow efficiency and functioning, contributes markedly to the societal costs of fatigue. This article proposes a noninvasive physical method for fatigue detection using a machine vision image algorithm. The main technology was implemented using a software framework based on optimized skin color segmentation and edge detection, as well as eye contour extraction. By integrating machine vision and an optimized Hove transform algorithm, our method mainly identifies fatigue based on the detected target's face, head gestures, mouth aspect ratio (MAR), and eye condition, and then triggers an alarm through an intelligent auxiliary device. Our evaluation results of facial image data analysis showed that with an ideal eye threshold of 0.3, PERCLOS-80 standard, MAR, and head gesture-nod frequency, the method can be used to detect fatigue data accurately and systematically, thereby fulfilling the purpose of alerting a group of high-risk drivers and preventing them from engaging in high-risk activities in an involuntary state.


Assuntos
Condução de Veículo , Acidentes de Trânsito/prevenção & controle , Software , Algoritmos , Fatores de Risco
2.
Sci Rep ; 11(1): 24053, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34912019

RESUMO

Nitrocellulose (NC) is widely used in both military and civilian fields. Because of its high chemical sensitivity and low decomposition temperature, NC is prone to spontaneous combustion. Due to the dangerous properties of NC, it is often dissolved in other organic solvents, then stored and transported in the form of a solution. Therefore, this paper took NC solutions (NC-S) with different concentrations as research objects. Under different atmospheric conditions, a series of thermal analysis experiments and different reaction kinetic methods investigated the influence of solution concentration and oxygen concentration on NC-S's thermal stability. The variation rules of NC-S's thermodynamic parameters with solution and oxygen concentrations were explored. On this basis, the spontaneous combustion characteristics of NC-S under actual industrial conditions were summarized to put forward the theoretical guidance for the spontaneous combustion treatment together with the safety in production, transportation, and storage.

3.
Polymers (Basel) ; 13(11)2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34064015

RESUMO

In recent years, the prosperous electric vehicle industry has contributed to the rapid development of lithium-ion batteries. However, the increase in the energy density of lithium-ion batteries has also created more pressing safety concerns. The emergence of a new flame-retardant material with the additive ethoxy (pentafluoro) cyclotriphosphazene can ameliorate the performance of lithium-ion batteries while ensuring their safety. The present study proposes a new polymer composite flame-retardant electrolyte and adopts differential scanning calorimetry (DSC) and accelerating rate calorimetry to investigate its thermal effect. The study found that the heating rate is positively correlated with the onset temperature, peak temperature, and endset temperature of the endothermic peak. The flame-retardant modified polymer electrolyte for new lithium-ion batteries has better thermal stability than traditional lithium-ion battery electrolytes. Three non-isothermal methods (Kissinger; Kissinger-Akahira-Sunose; and Flynn-Wall-Ozawa) were also used to calculate the kinetic parameters based on the DSC experimental data. The apparent activation energy results of the three non-isothermal methods were averaged as 54.16 kJ/mol. The research results can provide valuable references for the selection and preparation of flame-retardant additives in lithium-ion batteries.

4.
Polymers (Basel) ; 13(5)2021 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-33652664

RESUMO

Lithium-ion batteries with conventional LiPF6 carbonate electrolytes are prone to failure at high temperature. In this work, the thermal stability of a dual-salt electrolyte of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium difluoro(oxalato)borate (LiODFB) in carbonate solvents was analyzed by accelerated rate calorimetry (ARC) and differential scanning calorimetry (DSC). LiTFSI-LiODFB dual-salt carbonate electrolyte decomposed when the temperature exceeded 138.5 °C in the DSC test and decomposed at 271.0 °C in the ARC test. The former is the onset decomposition temperature of the solvents in the electrolyte, and the latter is the LiTFSI-LiODFB dual salts. Flynn-Wall-Ozawa, Starink, and autocatalytic models were applied to determine pyrolysis kinetic parameters. The average apparent activation energy of the dual-salt electrolyte was 53.25 kJ/mol. According to the various model fitting, the thermal decomposition process of the dual-salt electrolyte followed the autocatalytic model. The results showed that the LiTFSI-LiODFB dual-salt electrolyte is significantly better than the LiPF6 electrolyte in terms of thermal stability.

5.
Artigo em Inglês | MEDLINE | ID: mdl-30843829

RESUMO

Coplanar electrodes are used with the c-axis-oriented piezoelectric film to form the pure longitudinal mode and the pure shear mode solidly mounted resonators (SMRs). Aluminum and molybdenum are used as electrode materials to achieve different excitation pure shear mode and pure longitudinal mode. There is no need to make a bottom electrode or etch the piezoelectric layer, which simplifies the manufacturing and makes the structure stable. Furthermore, the cycle time of the process is significantly reduced. However, the control of the thickness of the Bragg reflectors, roughness control, and electrode photolithography are all challenging aspects of SMR manufacturing. In this study, ZnO piezoelectric film, which has a good electromechanical coupling factor and low transmission loss, was used as the c-axis-oriented piezoelectric film. An RF magnetron sputtering system was used to sputter a seed layer to encourage the growth of the zinc-oxide piezoelectric film and improve the c-axis orientation. The pure longitudinal mode and pure shear mode resonance signals were excited using the room temperature positive axis method. The quality factor and electromechanical coupling coefficient of the pure shear mode were 398% and 4.43%, respectively. The quality factor and electromechanical coupling coefficient of the pure longitudinal mode were 171% and 3.83%, respectively. Stability and feature recognition were accomplished in the pure longitudinal mode and the pure shear mode via a simplified and accelerated manufacturing process using electrodes with the same specifications.

6.
Sci Rep ; 9(1): 1592, 2019 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-30733558

RESUMO

Ethanolamine is a critical chemical for petrochemical enterprises. When corrosion occurs in pipelines, equipment, and containers in petrochemical enterprises, minute amounts of metal ions are released. In this study, the thermal decomposition and nonisothermal kinetics of monoethanolamine (MEA) and MEA mixed with copper and zinc ions were analyzed using thermogravimetry (TG) and differential scanning calorimetry (DSC). The TG tests revealed that MEA mixed with copper (II) and zinc (II) began thermal decomposition at 75.2 and 60.3 °C, respectively, whereas pure MEA began thermal decomposition at 89.7 °C. Two exothermic peaks were observed in the DSC curves for MEA mixed with copper (II) and zinc (II), and thermokinetic parameters were obtained from DSC data. The apparent activation energy (Ea) of each stage was calculated using several nonisothermal kinetic methods, namely the ASTM E698, Kissinger-Akahira-Sunose, Starink, and Flynn-Wall-Ozawa methods. The Ea of pure MEA was 28.7 ± 2.5 kJ/mol, whereas that of the copper and zinc mixtures were 80.5 ± 1.1 and 46.8 ±1.7 kJ/mol, respectively. The results can be used to improve the intrinsic safety of storage tanks and petrochemical plants.

7.
Int J Nanomedicine ; 11: 729-41, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27013873

RESUMO

In this work, silica nanofibers (SNFs) were prepared by an electrospinning method and modified with poly-d-lysine (PDL) or (3-aminopropyl) trimethoxysilane (APTS) making biocompatible and degradable substrates for neuronal growth. The as-prepared SNF, modified SNF-PDL, and SNF-APTS were evaluated using scanning electron microscopy, nitrogen adsorption/desorption isotherms, contact angle measurements, and inductively coupled plasma atomic emission spectroscopy. Herein, the scanning electron microscopic images revealed that dissolution occurred in a corrosion-like manner by enlarging porous structures, which led to loss of structural integrity. In addition, covalently modified SNF-APTS with more hydrophobic surfaces and smaller surface areas resulted in significantly slower dissolution compared to SNF and physically modified SNF-PDL, revealing that different surface modifications can be used to tune the dissolution rate. Growth of primary hippocampal neuron on all substrates led to a slower dissolution rate. The three-dimensional SNF with larger surface area and higher surface density of the amino group promoted better cell attachment and resulted in an increased neurite density. This is the first known work addressing the degradability of SNF substrate in physiological conditions with neuron growth in vitro, suggesting a strong potential for the applications of the material in controlled drug release.


Assuntos
Materiais Biocompatíveis/química , Eletroquímica , Hipocampo/fisiologia , Nanofibras/química , Neurônios/fisiologia , Dióxido de Silício/química , Engenharia Tecidual/métodos , Animais , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Embrião de Mamíferos/citologia , Embrião de Mamíferos/fisiologia , Hipocampo/citologia , Microscopia Eletrônica de Varredura , Neurônios/citologia , Porosidade , Ratos , Silanos/química , Propriedades de Superfície
8.
Mol Microbiol ; 94(3): 506-21, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25213466

RESUMO

Cytoplasmic microtubules (MTs) serve as a rate-limiting factor for hyphal tip growth in the filamentous fungus Aspergillus nidulans. We hypothesized that this function depended on the MT plus end-tracking proteins (+TIPs) including the EB1 family protein EBA that decorated the MT plus ends undergoing polymerization. The ebAΔ mutation reduced colony growth and the mutant hyphae appeared in an undulating pattern instead of exhibiting unidirectional growth in the control. These phenotypes were enhanced by a mutation in another +TIP gene clipA. EBA was required for plus end-tracking of CLIPA, the Kinesin-7 motor KipA, and the XMAP215 homologue AlpA. In addition, cytoplasmic dynein also depended on EBA to track on most polymerizing MT plus ends, but not for its conspicuous appearance at the MT ends near the hyphal apex. The loss of EBA reduced the number of cytoplasmic MTs and prolonged dwelling times for MTs after reaching the hyphal apex. Finally, we found that colonies were formed in the absence of EBA, CLIPA, and NUDA together, suggesting that they were dispensable for fundamental functions of MTs. This study provided a comprehensive delineation of the relationship among different +TIPs and their contributions to MT dynamics and unidirectional hyphal expansion in filamentous fungi.


Assuntos
Aspergillus nidulans/crescimento & desenvolvimento , Aspergillus nidulans/metabolismo , Hifas/crescimento & desenvolvimento , Hifas/metabolismo , Proteínas dos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Aspergillus nidulans/genética , Citoplasma/metabolismo , Deleção de Genes , Proteínas dos Microtúbulos/genética
9.
Mol Biol Cell ; 20(12): 2874-84, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19386763

RESUMO

In the filamentous fungus Aspergillus nidulans, cytokinesis/septation is triggered by the septation initiation network (SIN), which first appears at the spindle pole body (SPB) during mitosis. The coiled-coil protein SNAD is associated with the SPB and is required for timely septation and conidiation. We have determined that SNAD acted as a scaffold protein that is required for the localization of the SIN proteins of SIDB and MOBA to the SPB. Another scaffold protein SEPK, whose localization at the SPB was dependent on SNAD, was also required for SIDB and MOBA localization to the SPB. In the absence of either SEPK or SNAD, SIDB/MOBA successfully localized to the septation site, indicating that their earlier localization at SPB was not essential for their later appearance at the division site. Unlike their functional counterparts in fission yeast, SEPK and SNAD were not required for vegetative growth but only for timely septation. Furthermore, down-regulation of negative regulators of the SIN suppressed the septation and conidiation phenotypes due to the loss of SNAD. Therefore, we conclude that SPB localization of SIN components is not essential for septation per se, but critical for septation to take place in a timely manner in A. nidulans.


Assuntos
Aspergillus nidulans/citologia , Aspergillus nidulans/metabolismo , Proteínas de Ciclo Celular/metabolismo , Citocinese , Proteínas Fúngicas/metabolismo , Fuso Acromático/metabolismo , Actomiosina/metabolismo , Regulação para Baixo , Proteínas Ativadoras de GTPase/metabolismo , Mutação/genética , Transporte Proteico , Homologia de Sequência de Aminoácidos , Fatores de Tempo
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