bluuebunny/crossref_metadata_2025 huggingface dataset:
STRENGTH SIZE EFFECT IN FIBER COMPOSITES FAILING UNDER LONGITUDINAL AND TRANSVERSE COMPRESSION
Authors: XUE JING , KIRANE KEDAR
Published: November 2021

The size effect in the structural strength of fiber reinforced composites has been typically analyzed for tensile failures. However, this is not true for the equally important compressive failures, primarily due to the difficulties in conducting compression tests on specimens of multiple sizes. These size effects are analyzed here numerically for two important compressive failure mechanisms in composites, viz. (i) fiber kink bands forming under longitudinal compression (typically accompanied by axial splitting matrix cracks) and (ii) inclined shear cracks forming under transverse compression. The former mechanism is modeled by a semi-multiscale microplane model, while the latter by the fixed crack model. Both models are calibrated and verified using available test data on carbon fiber composites and then used to predict the failure and load bearing capacities of geometrically scaled pre-cracked specimens of different sizes. In all cases, the predicted failure is found to be of a propagating nature, accompanied by release of strain energy from the specimen causing a distinct size effect in the nominal strength. For the composite considered here, under longitudinal compression, the fracture process zone (FPZ) is found to be fairly small (<1 mm) and the strength size effect is seen to follow linear elastic fracture mechanics (LEFM). The size effect deviates from LEFM for smaller specimen sizes due to increased flaw size insensitivity but cannot be fitted by Bažant's size effect law since the geometric similarity of the failure mode is lost. On the other hand, under transverse compression the FPZ is found to be much larger (34 to 42 mm) and the size effect is found to obey Bažant's size effect law, deviating from LEFM. The failure is geometrically similar despite being inclined to the pre-crack. These findings provide evidence of the general applicability of fracture mechanics-based size effect laws to compressive failure in fiber composites, and prompt suitable experimental investigations.
FATIGUE FAILURE OF FIBROUS COMPOSITE BASED ON MULTISCALE APPROACH
Authors: KADLEC LAUREN , HALLER CASSANDRA , KWON YOUNG , PARK SOO-JEONG , KIM YUN-HAE
Published: November 2021

A framework was presented for a fatigue failure model of fibrous composites using a multiscale approach, which uses the fatigue data of the fiber and matrix materials, respectively. Using this model, fatigue failure of fibrous composite materials and structures can be predicted from the constituent material behaviors. To that end, fiber bundles were tested under cyclic loading to determine their residual strength and stiffness. A successful completion of the model is expected to replace many fatigue tests as the configuration of the fibrous composite is varied.
A MULTISCALE MODELING AND X-RAY CT EXPLORATION OF BEARING FAILURE MECHANISMS IN A COUNTERSUNK BOLTED COMPOSITE STRUCTURE
Authors: CUI XIAODONG , XIAO JIAN , LUA JIM , KARIYAWASAM SUPUN , FULGHUM ETHAN , SAATHOFF CALEB , SENEVIRATNS WARUNA
Published: November 2021

To investigate the failure mechanism in composite bolted joints, an in-situ X-Ray computed tomography (XCT) technique was developed and single shear bearing (SSB) tests were performed with quasi-isotropic layup. High-fidelity XCT was explored for the detection and characterization of bearing failure in bolted composite components without removing the fastener. A novel load frame was also introduced for in-situ XCT scan and a preliminary scan was performed. A micro-macro coupling modeling approach was proposed on the basis of continuum damage mechanics (CDM) method and a static bearing model, which was based on micromechanics analysis to consider the residual stress after fiber kinking and matrix cracking under compression in the bearing region. The SSB specimens were modified using a larger bolt diameter to avoid bolt failure and achieve extensive bearing failure. The developed modeling approach was verified using SSB test data by comparing the predicted load displacement response with experimental measurement and the failure patterns obtained from XCT scanning images.
VERTICALLY-ALIGNED CARBON NANOTUBE (VACNT)-REINFORCEMENT FOR STRENGTH AND LIFE ENHANCEMENT OF COMPOSITE AEROSTRUCTURES
Authors: SHAH, PRANAV D. , LI RICHARD
Published: November 2021

Laminated composites used in lightweight airframe structures offer higher in-plane strength and stiffness to weight ratio when compared with metals but suffer from weaker out-of-plane properties. Using a building-block approach, vertically-aligned carbon nanotube (VACNT) reinforcement technology is evaluated for its efficacy in enhancing the through-thickness properties of composite laminates necessary for reducing the weight, improving the damage tolerance and extending the fatigue life of composite airframe structures. With additional insight into how VACNT reinforcement performance scales, it is anticipated that the conclusion of this evaluation will facilitate the increase in the technology readiness level (TRL) of VACNT-applications for composite airframes from three to four [1]. The content of this document includes information relevant to the planning and fabrication activities of the program, with experimental testing of articles forthcoming.
ORTHOTROPIC DAMAGE MODEL USING TSAI-WU FAILURE CRITERIA
Authors: ARRUDA M. R. T. , ALMEIDA-FERNANDES, L. , CASTRO L. , CORREIA J. R.
Published: November 2021

This paper presents a novel approach concerning the development of an orthotropic damage model, based on the original plane Tsai-Wu failure criteria. In its original formulation, the Tsai-Wu is a mode independent criterion only capable of acknowledging the existence of damage in a certain point of the material. It is not capable of identifying if the damage is located in the fiber, matrix or intralaminar zone. This work plans to fill this gap in knowledge by providing a simple method, based on equivalent stress and strains, that identifies the failure modes when the Tsai-Wu failure criteria is near the on-set of damage. Using this novel method, it is possible to implement classical damage evolutions constitutive laws based on the MTL formulation. At the moment the proposed damage formulation is based on plane stress space and Mode I fracture, but it is expected in the future to evolve in to a full 3D damage model. The damage model is implemented in the commercial finite element software ABAQUS using user-subroutine UMAT, and all numerical models are compared with the experimental results.
POST MECHANICAL FAILURE FIRE DAMAGE CHARACTERIZATION OF GRAPHITE/EPOXY COMPOSITES
Authors: MOTE ANIKET , OUIDADI HASNAA , BOUSHAB DOUNIA , PRIDDY MATTHEW , KUNDU SANTANU , PITTMAN, JR. CHARLES , GRUNLAN JAIME , WANG QINGSHENG , LACY, JR. THOMAS E.
Published: November 2021

Fire damage involving mechanically failed composite aircraft structures can dramatically alter their exposed surface characteristics in ways that inhibit fire forensic analyses. In this work, the effects of fire exposure on mechanically failed Cytec T40- 800/Cycom® 5215 graphite/epoxy composites were examined. Coupon level vertical fire tests were performed on mechanically failed unnotched compression and in-plane shear graphite/epoxy specimens. The fire damage was characterized by visual inspection and scanning electron microscopy. The fire damage development in the specimens involved a concurrent and sequential interaction between multiple physical, chemical, and thermal processes. This damage included melt dripping, matrix decomposition, char, soot, matrix cracking, delamination, and residual thickness increases due to explosive outgassing. The composite thermal degradation due to heat conduction, combustion, and/or thermal deformation was significantly affected by the specimen layup, ply orientation relative to the heat source, and the fracture surface morphology. Plies burned with fibers oriented parallel to the flame axis conducted heat into the interior of the composite. This resulted in melt dripping, internal pockets of matrix decomposition, and surface char deposition that, in some cases, completely obscured pertinent aspects of fiber fracture surface morphology. In contrast, plies burned with fibers oriented perpendicular to the flame axis acted like a thermal protection layer that impeded (slowed) heat transfer to the specimen’s interior. Furthermore, the thermal damage development was influenced by the specimen layup and the total available free surface area created during mechanical failure. Specimens with more free surface area promoted better airflow and oxygen availability for combustion and sustained far more thermal degradation for given fire exposure. Key fractographic features in exposed fiber bundles were destroyed due to severe thermal oxidation and thinning. A thorough understanding of these coupon-level fire tests represents a critical first step in developing a coherent strategy for the Federal Aviation Authority post-crash forensic analysis of composite aircraft structures.
CURE BEHAVIOR OF NANOSTRUCTURED HIERARCHICAL COMPOSITES WITH FUNCTIONALIZED CARBON NANOTUBES
Authors: SUNG DAE HAN , DOSHI SAGAR M. , RIDER ANDREW N. , THOSTENSON ERIK T.
Published: November 2021

Electrophoretic deposition is a promising technique to hybridize nanomaterials with conventional reinforcing materials for multifunctional applications. It utilizes the principle of electrophoresis, where electric potential drives charged particles dispersed in a liquid towards counter-charged substrates. Polymer matrix can be infused into the hybridized fibers to produce hierarchical polymer composites with reinforcements spanning several orders of magnitude in scale. This research addresses a key challenge associated with nanostructured composites produced by first dispersing the nanoscale reinforcement into the polymer matrix and then infusing into the fiber reinforcement (direct mix/infusion method). The key limitation is on the volume fraction of the nanoscale particles due to the drastic increase of the resin viscosity and the potential filtering effect of the particles during resin infusion. Our model system consists of an aqueous dispersion of carbon nanotubes (CNT) functionalized with a cationic polymer, polyethyleneimine (PEI), non-conductive glass fabric and epoxy resin. Amine functional groups of PEI are protonated under mildly acidic conditions, producing positively charged CNTs. A stable dispersion is formed through repulsive electrostatic forces among charged CNTs, which also facilitates deposition under applied electric fields. CNT-PEI films uniformly deposited via EPD on each filament throughout the fabric form a unique interface between reinforcing fiber and epoxy matrix. Concentrated amines from CNT-PEI coatings possibly alter the curing mechanism of infused epoxy resin, thereby creating the graded mechanical properties at the interface. In this study, curing kinetics and thermomechanical properties of epoxy resin are investigated with added PEI which provides stoichiometrically excessive amines. It is expected that the curing temperature profile can be designed to optimize the interfacial properties of electrophoretically processed CNT-PEI multiscale composites.
A COMPLEX POTENTIAL APPROACH TO MICROMECHANICS OF UNIDIRECTIONAL COMPOSITES
Authors: RUSSELL STEVEN G.
Published: November 2021

Complex potential methods for the solution of two-dimensional boundary value problems in linear elasticity are used to perform micromechanics analysis of unidirectional composites. The composite microstructure is idealized as a square array of unit cells subjected to prescribed strains. Unit cell analyses are performed for plane strain and anti-plane strain conditions to study the interaction of the fiber and matrix materials. The unit cell solutions are used to derive predictions for the ply moduli, Poisson’s ratios and coefficients of thermal expansion, which are shown to agree with the results of other methods. Applications to strength prediction are briefly discussed, and the detailed stress field results that can be generated using the approach are illustrated.
IN-SITU MEASUREMENT OF PERMEABILITY BETWEEN CARBON FIBER/RESIN
Authors: ENDO MASAKI , SAITO HIROSHI , KIMPARA ISAO
Published: November 2021

Carbon fiber reinforced plastic (CFRP) is a composite material in which carbon fibers are impregnated with resin to achieve both high strength and high rigidity. CFRP is an excellent material, but it is expensive in terms of materials, manufacturing costs, and capital investment, and it takes a lot of time to complete a product. In order to solve these problems, the demand for de-autoclaving has been increasing in recent years. If molding can be performed without autoclaving, it will be possible to reduce costs and improve productivity in terms of materials and capital investment costs.
MICROSTRUCTURAL CORRELATIONS IN SHORT-ALIGNED GLASS FIBER COMPOSITES
Authors: ROJAS G., CAMILO A. , SCHÖBERL ERICH , LONGANA MARCO L. , LOMOV STEPAN , SWOLFS YENTL
Published: November 2021

Research shows that in unidirectional composites, fiber breaks and clusters of fiber breaks play a role in the failure onset of the composites [1]. So far, we know no attempts to the date have been made to analyze the fiber break development in short-aligned fiber composites, specifically using E-glass HYBON 2026. O[1]ur challenge is to determine whether there is a similar behavior in aligned short composites and its relationship with the microstructural parameter of fiber orientation distribution. This is important as it is measurable parameter to add value to recycled fiber composites. The more aligned the composite the higher mechanical properties and the higher the added value for recycling. We focused on using synchrotron x-ray computed tomography while performing hold-at-displacement scans to evaluate the fiber microstructure. We found the fiber breaks do not have the same orientation distribution as the non-broken fibers.
MULTISCALE MODELING OF THE EFFECTIVE THERMAL CONDUCTIVITY OF 2D WOVEN COMPOSITES BY MECHANICS OF STRUCTURE GENOME AND NEURAL NETWORKS
Authors: LIU XIN , PENG BO , YU WENBIN
Published: November 2021

A data-driven multiscale modeling approach is developed to predict the effective thermal conductivity of two-dimensional (2D) woven composites. First, a two-step homogenization approach based on mechanics of structure genome (MSG) is developed to predict effective thermal conductivity. The accuracy and efficiency of the MSG model are compared with the representative volume element (RVE) model based on three-dimensional (3D) finite element analysis (FEA). Then, the simulation data is generated by the MSG model to train neural network models to predict the effective thermal conductivity of three 2D woven composites. The neural network models have mixed input features: continuous input (e.g., fiber volume fraction and yarn geometries) and discrete input (e.g., weave patterns). Moreover, the neural network models are trained with the normalized features to enable reusability. The results show that the developed data-driven models provide an ultra-efficient yet accurate approach for the thermal design and analysis of 2D woven composites.
EXPERIMENTALLY VALIDATED SIMULATIONS OF BLIND HOLE DRILLING IN 3D WOVEN CARBON/EPOXY COMPOSITE WITH PROCESSING-INDUCED RESIDUAL STRESSES
Authors: LEOS ARTURO , VASYLEVSKYI KOSTIANTYN , TSUKROV IGOR , GROSS TODD , DRACH BORYS
Published: November 2021

Manufacturing-induced residual stresses in carbon/epoxy 3D woven composites arise during cooling after curing due to a large difference in the coefficients of thermal expansion between the carbon fibers and the epoxy matrix. The magnitudes of these stresses appear to be higher in composites with high throughthickness reinforcement and in some cases are sufficient to lead to matrix cracking. This paper presents a numerical approach to simulation of development of manufacturing-induced residual stresses in an orthogonal 3D woven composite unit cell using finite element analysis. The proposed mesoscale modeling combines viscoelastic stress relaxation of the epoxy matrix and realistic reinforcement geometry (based on microtomography and fabric mechanics simulations) and includes imaginginformed interfacial (tow/matrix) cracks. Sensitivity of the numerical predictions to reinforcement geometry and presence of defects is discussed. To validate the predictions, blind hole drilling is simulated, and the predicted resulting surface displacements are compared to the experimentally measured values. The validated model provides an insight into the volumetric distribution of residual stresses in 3D woven composites. The presented approach can be used for studies of residual stress effects on mechanical performance of composites and strategies directed at their mitigation.
ACHIEVING REALISTIC TOW FIBER VOLUME FRACTIONS IN TEXTILE COMPOSITE MODELS BY INDUCING FIBER ENTANGLEMENT
Authors: BARLOW GEORGE , SCHEY MATHEW , STAPLETON SCOTT
Published: November 2021

Modeling composites can be an effective way to understand how a part will perform without requiring the destruction of costly specimens. By combining artificial fiber entanglement with manufacturing process simulation, a method was developed to create fiber bundle models using entanglement to control the fiber volume fraction. This fiber entanglement generation uses three parameters, probability of swapping (p_(r_S )), swapping radius standard deviation (r_(σ_S )), and the swapping plane spacing (l_S), to control the amount of entanglement within the fiber bundle. A parametric study was conducted and found that the more entanglement within a fiber bundle, the more compression mold pressure required to compact the fiber bundle to the same fiber volume fraction as that required for a less entangled bundle. This artificial fiber entanglement and manufacturing process simulation method for creating fiber bundles shows the potential to be able to create bundles with controlled final volume fraction using a desired mold compression pressure.
HYDRAULIC BULGE TESTING TO COMPARE FORMABILITY OF CONTINUOUS AND STRETCH BROKEN CARBON FIBER PREPREG LAMINATES
Authors: SHCHEMELININ YONI , NELSON JARED W. , AMENDOLA ROBERTA
Published: November 2021

The use of carbon fiber reinforced polymer composites has increased with the increased need for high-strength, low-density materials, particularly in the aviation industry. Stretch broken carbon fiber (SBCF) is a form of carbon fiber created by the randomized breaking of aligned fibers in a tow at inherent flaw points, resulting in a material constituted of collimated fiber fragments longer than chopped fibers. While continuous carbon fibers possess desirable material properties, the limited formability prevents their wider adoption. SBCF composites exhibit pseudo-plastic deformation that can potentially enable the use of traditional metal forming techniques like stamping and press forming well established in mass production applications. To investigate the formability of SBCF composites prepared with either continuous or stretch broken Hexcel IM-7 12K fiber, impregnated with Huntsman RDM 2019-053 resin, hydraulic bulge testing was performed to explore the strain behavior under biaxial stress conditions at elevated temperature under atmospheric pressure. Initial results show better formability of SBCF compared to continuous fiber, characterized by the axisymmetric response to the applied stress.
Relação dicotômica entre Estado e mercado? uma análise da lei de liberdade econômica à luz da Constituição
Authors: Juruena Cynthia Gruendling , Rodrigues Reck Janriê
Published: November 2021

O presente artigo analisou a recentemente editada Lei 13.874/19 – Declaração de Direitos de Liberdade Econômica – e seus reflexos no Direito Administrativo Econômico, concedendo especial ênfase ao poder regulatório do Estado. Em um primeiro momento, analisou-se o Estado regulador na Constituição da República Federativa de 1988, sobretudo com a reforma gerencial (1995), que implicou em mudanças nos âmbitos da Administração Pública e da ordem econômica. Após uma breve contextualização dos fundamentos e finalidade da ordem econômica na Constituição, examinou-se a exposição de motivos redigida pelos autores do projeto que originou a Lei 13.874/19. Ao final, realizou-se uma análise de alguns aspectos da legislação à luz da Constituição de 1988, principalmente no que tange à regulação. O problema de pesquisa que norteou a elaboração deste trabalho foi a avaliação da compatibilidade da Lei de Liberdade Econômica com o que preceitua a Constituição de 1988. A metodologia de pesquisa adotada foi o método hipotético-dedutivo, partindo-se da hipótese de que a legislação se coaduna com a CRFB/88. Os resultados preliminares foram no sentido de que a Constituição não realiza uma separação dicotômica entre Estado e Mercado, mas sim, uma atuação conjunta e complementar a fim de alcançar os pressupostos constitucionais.
Direito, hermenêutica e inteligência artificial: construindo pontes entre a decisão judicial, compreensão existencial e mecanismos de machine learning
Authors: Hartmann Gabriel Henrique , Hommerding Adalberto Narciso
Published: November 2021

Este texto discute a imbricação Direito, Hermenêutica e Inteligência Artificial (I.A.): a possibilidade hermenêutica de construção de decisões judiciais a partir de mecanismos de machine learning. O texto descreve o pensar hermenêutico, que é um pensar que medita, capaz de compreender, entender e questionar a própria existência do ser, e, ao descrever conceitos atrelados a I.A., machine learning e aprendizado de máquina, busca imbricar Hermenêutica e I.A., tentando verificar se é ou não possível construir hermeneuticamente decisões judiciais a partir dos mecanismos de I.A., diante da dificuldade da máquina de pensar hermeneuticamente. O intuito do presente texto, portanto, é buscar afirmar se já há ou não possibilidade de conciliar Direito, Hermenêutica e I.A., no sentido de a máquina proferir decisões judiciais que sejam melhores que as do juiz, na medida em que consiga conter a subjetividade judicial sempre presente nas decisões.
Estado de exceção, resistência e violência: um estudo comparativo a partir de Giorgio Agamben e Hannah Arendt
Authors: Ribeiro Karla Pinhel
Published: November 2021

Dentro da teoria do estado de exceção, podemos dizer que o sistema jurídico do Ocidente apresenta uma dupla estrutura, formada por dois elementos heterogêneos e, no entanto, coordenados: um elemento normativo e jurídico em sentido estrito – a potestas – e um elemento anômico e metajurídico – a auctoritas. O estado de exceção é o dispositivo que deve, em última instância, articular e manter juntos os dois aspectos da máquina jurídico-política, instituindo um limiar de indecibilidade entre anomia e nomos, entre vida e direito, entre auctoritas e potestas. O ponto central do debate filosófico jurídico, tanto no direito de resistência quanto no estado de exceção, quanto ao que está realmente em questão é a existência de uma ação em si extra-jurídica. No plano da filosofia do direito, a questão da resistência consiste em um debate que apresenta duas teses opostas: a de que o direito deve coincidir com a norma e aquela que, em oposição, defende que o âmbito do direito excede a norma, mas que em última análise, as duas posições opostas encontram-se solidárias a uma mesma condição, na exclusão da existência de uma esfera da ação humana que escape totalmente ao direito.
Fragilidade do pluralismo democrático, uma abordagem a partir de Tocqueville
Authors: Dos Reis Helena Esser
Published: November 2021

Resumo: Desde a concepção iluminista de tolerância, a desconfiança em relação às certezas irretorquíveis e o acolhimento do outro passaram a orientar relações sociais e políticas pluralistas e democráticas, tendo em vista a proteção da pessoa e a promoção da justiça e da paz. Contudo, há uma permanente tensão entre reivindicações de direitos e conquistas garantidas, que se enraíza em questões sociais e culturais associadas à noção do tolerável ou do que pode ser admitido como equiparável, simétrico e, portanto respeitável, apesar de diferente. No âmbito deste artigo, partindo de uma concepção de tolerância religiosa como origem do pluralismo democrático, quer-se investigar, a tênue fronteira que separa o aceitável do não-aceitável, o cidadão daquele que, apesar de se assim chamado, não pode exercer sua cidadania, sua voz não é ouvida, não participa. A discussão acerca da fragilidade do pluralismo democrático será feita a partir da análise do pensamento de Alexis de Tocqueville. A análise de seu pensamento é bastante importante porque, tendo caracterizado a democracia pela confluência entre condições sociais de igualdade e condições políticas de liberdade, quando visitou os Estados Unidos em 1830 explicita, com certa ironia, existência de democracia exclusivamente entre os “anglo-americanos”. Narrando a situação social e política vivida pelos negros e indígenas que habitavam a América do Norte, repudia e denuncia a exclusão e a violência às quais estavam submetidos. Embora Tocqueville afirme que a exclusão de negros e indígenas da democracia norte-americana seja uma ameaça à própria democracia, sua concepção parece admitir a integração pela assimilação da cultura democrático-européia por parte dos negros e indígenas.  A tensão entre “anglo-americanos”, negros e indígenas existente, será objeto de análise a fim de discutir a possibilidade de inclusão do outro e os limites do pluralismo democrático confrontando ideias presentes em A Democracia na América e Cartas Mexicanas, escritas por Tocqueville na mesma época de sua viagem aos Estados Unidos, e outros escritos referentes à discursos políticos proferidos na Assembleia Francesa.
Brain Levels of Reduced Glutathione and Malondialdehyde in Honey-Fed Wistar Rats
Authors: Awhin Prosper Ejiro , Uzuegbu Ugochukwu Enyinnaya , Ojugbeli Evelyn , Otomewo Lily Oghenevovwero
Published: November 2021

This research sought to verify the effect of natural honey on brain levels of malondialdehyde (MDA) and reduced glutathione (GSH) in rats. Forty nine male and female Wistar rats were used for the experiment. The rats were allotted into seven groups of seven rats in each group. For one month, rats in groups 1-4 were fed with 100% feed, 20%, 30% and 40% honey respectively. The remaining 3 groups were fed with amounts of refined fructose and glucose equivalent to those in 20%, 30% and 40% honey. The brains were then excised, homogenized and used for biochemical analysis. Results showed that honey in all concentrations caused a significant increase in GSH levels but only 20% honey caused a significant decrease in MDA level when compared with control. Also, fructose feeding at 20%, 30% and 40% increased both brain GSH and MDA levels. Consequently, the influence of GSH as an antioxidant against brain lipid peroxidation needs further studies for better understanding since an increase in GSH for fructose- and honey-fed rats did not cause a simultaneous decrease in MDA content.
Thermal hydrolysis of olive leaves and stems to obtain fermentable sugars
Authors: Rodrigues Fabiele Schaefer , Silveira Norton Marozo , Kury Alexandre Gonçalves , Silva Jefferson Fagundes , Cunha Estêvão Santos Laureano , Tres Marcus Vinícius , Zabot Giovani Leone
Published: November 2021

Subcritical water hydrolysis was used for the pre-treatment of residues generated in olive groves. Fermentable sugars were produced from the lignocellulosic material found in olive leaves and stems. Firstly, moisture, ash, particle average diameter, and total extracts were measured. Afterward, subcritical water hydrolysis was carried out at 20 MPa in a 50 mL reactor. The influences of two temperatures (180 and 220 °C) and two water flow rates (10 and 20 mL min-1) on the sugars yields were evaluated. The concentration of sugars was 31.3 g L-1 at 180 °C and 10 mL min-1 in a reaction for 3 min, of which glucose was the major sugar (27.64 g L-1). Statistical analysis was performed using Sisvar® 5.6 software and the averages were compared through Tukey’s test, considering a significance level of 95% (p<0.05). For the treatments evaluated in this work, only xylose was statistically different in the treatments with different water flow rates. The highest values of xylose were obtained with 10 mL min-1, which were 1.82 g L-1 (180 °C) and 2.18 g L-1 (220 °C). The total inhibitors were high at 220 °C for all water flow rates, with a significant difference from the averages obtained at 180 °C.
High-transmission narrowband ultraviolet filter based on an aluminum laminated nanostructure on glass
Authors: Dong Miao , Cheng Haijuan , Cai Yi , Dai Fang , Wang Lingxue
Published: November 2021

We present an aluminum (Al) laminated nanostructure stacked on a glass substrate to produce highly transmitted narrowband ultraviolet (UV) filters. The laminated nanostructure was mainly composed of an Al nanohole array, and each Al nanohole had a coaxial Al nanoring at the bottom. This UV filter showed a single dominant peak with a high transmission over 50% and a narrow bandwidth less than 80 nm in the 200–400 nm waveband that was achieved based on the synergy of surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR). The electric field profiles of the laminated nanostructure indicate that SPR selects the transmission wavelength and LSPR contributes to single peak. This narrowband UV filter can be utilized in UV detectors.
Porous SiO2 coated dielectric metasurface with consistent performance independent of environmental conditions
Authors: Geromel René , Weinberger Christian , Brormann Katja , Tiemann Michael , Zentgraf Thomas
Published: November 2021

With the rapid advances of functional dielectric metasurfaces and their integration on on-chip nanophotonic devices, the necessity of metasurfaces working in different environments, especially in biological applications, arose. However, the metasurfaces’ performance is tied to the unit cell’s efficiency and ultimately the surrounding environment it was designed for, thus reducing its applicability if exposed to altering refractive index media. Here, we report a method to increase a metasurface’s versatility by covering the high-index metasurface with a low index porous SiO2 film, protecting the metasurface from environmental changes while keeping the working efficiency unchanged. We show, that a covered metasurface retains its functionality even when exposed to fluidic environments.
Tunable terahertz metamaterial wideband absorber with liquid crystal
Authors: Deng Guangsheng , Hu Hualong , Mo Haisheng , Xu Junjie , Yin Zhiping , Lu Hongbo , Hu Minggang , Li Jian , Yang Jun
Published: November 2021

In this paper, a tunable metamaterial absorber (MA) based on liquid crystal (LC) with wideband absorption is presented. The design and absorption principle of the absorber is introduced, and the simulation analysis is conducted. The results show that the center resonant frequency of the proposed absorber is 130.0 GHz without a bias voltage. When the bias voltage increases to saturation, the center resonant frequency of the absorber is tuned to 119.9 GHz, with a frequency tunability of 7.8%. Moreover, the tunable absorber exhibits wideband absorption characteristics and maintains absorption above 90% in the frequency range of 127.7 GHz to 132.3 GHz with no bias voltage, with a relative absorption bandwidth of 3.5%. While under the saturation voltage, absorption greater than 90% can be achieved from 117.9 to 121.8 GHz, with a relative absorption bandwidth of 3.3%. The wideband absorption effect of the proposed LC-based tunable MA makes it a promising candidate for applications such as electromagnetic shielding and stealth.
ΔFBA—Predicting metabolic flux alterations using genome-scale metabolic models and differential transcriptomic data
Authors: Ravi Sudharshan , Gunawan Rudiyanto
Published: November 2021

Genome-scale metabolic models (GEMs) provide a powerful framework for simulating the entire set of biochemical reactions in a cell using a constraint-based modeling strategy called flux balance analysis (FBA). FBA relies on an assumed metabolic objective for generating metabolic fluxes using GEMs. But, the most appropriate metabolic objective is not always obvious for a given condition and is likely context-specific, which often complicate the estimation of metabolic flux alterations between conditions. Here, we propose a new method, called ΔFBA (deltaFBA), that integrates differential gene expression data to evaluate directly metabolic flux differences between two conditions. Notably, ΔFBA does not require specifying the cellular objective. Rather, ΔFBA seeks to maximize the consistency and minimize inconsistency between the predicted flux differences and differential gene expression. We showcased the performance of ΔFBA through several case studies involving the prediction of metabolic alterations caused by genetic and environmental perturbations inEscherichia coliand caused by Type-2 diabetes in human muscle. Importantly, in comparison to existing methods, ΔFBA gives a more accurate prediction of flux differences.
Survival and predictors of death in tuberculosis/HIV coinfection cases in Porto Alegre, Brazil: A historical cohort from 2009 to 2013
Authors: Brand Évelin Maria , Rossetto Maíra , Hentges Bruna , Winkler Gerson Barreto , Duarte Erica Rosalba Mallmann , Silva Lucas Cardoso da , Leal Andrea Fachel , Knauth Daniela Riva , Silva Danielle Lodi , Mantese George Henrique Aliatti , Volpato Tiane Farias , Bobek Paulo Ricardo , Dellanhese Amanda Pereira Ferreira , Teixeira Luciana Barcellos
Published: November 2021

Background

Tuberculosis is a curable disease, which remains the leading cause of death among infectious diseases worldwide, and it is the leading cause of death in people living with HIV. The purpose is to examine survival and predictors of death in Tuberculosis/HIV coinfection cases from 2009 to 2013.

Methods

We estimated the survival of 2,417 TB/HIV coinfection cases in Porto Alegre, from diagnosis up to 85 months of follow-up. We estimated hazard ratios and survival curves.

Results

The adjusted risk ratio (aRR) for death, by age, hospitalization, and Directly Observed Treatment was 4.58 for new cases (95% CI: 1.14–18.4), 4.51 for recurrence (95% CI: 1.11–18.4) and 4.53 for return after abandonment (95% CI: 1.12–18.4). The average survival time was 72.56 ± 1.57 months for those who underwent Directly Observed Treatment and 62.61 ± 0.77 for those who did not.

Conclusions

Case classification, age, and hospitalization are predictors of death. The occurrence of Directly Observed Treatment was a protective factor that increased the probability of survival. Policies aimed at reducing the mortality of patients with TB/HIV coinfection are needed.
School types in adolescence and subsequent health and well-being in young adulthood: An outcome-wide analysis
Authors: Chen Ying , Hinton Christina , VanderWeele Tyler J.
Published: November 2021

While past empirical studies have explored associations between types of primary and secondary schools and student academic achievement, outcomes beyond academic performance remain less well-understood. Using longitudinal data from a cohort of children (N = 12,288, mean age = 14.56 years) of nurses, this study examined associations between the types of schools participants attended in adolescence and a wide range of subsequent psychological well-being, social engagement, character strengths, mental health, health behavior and physical health outcomes. Results in this sample suggested little difference between attending private independent schools and public schools across outcomes in young adulthood. There were, however, notable differences in subsequent outcomes comparing homeschooling and public schools, and possibly some evidence comparing religious schools and public schools. Specifically, there was some evidence that attending religious schools versus public schools was associated with a higher likelihood of frequent religious service attendance and becoming registered voters, a lower risk of overweight/obese, fewer lifetime sexual partners, and a higher risk of subsequently being binge drinkers; however, these associations were not robust to correction for multiple testing. Homeschooling compared with public schooling was associated with subsequently more frequent volunteering (ß = 0.33, 95% CI = 0.15, 0.52), greater forgiveness (ß = 0.31, 95% CI = 0.16, 0.46), and more frequent religious service attendance (Risk Ratio [RR] = 1.51, 95% CI: 1.27, 1.80), and possibly also with greater purpose in life, less marijuana use, and fewer lifetime sexual partners, but negatively associated with college degree attainment (RR = 0.77, 95% CI: 0.67, 0.88) and possibly with greater risk of posttraumatic stress disorder. These results may encourage education stakeholders to consider a wider range of outcomes beyond academic performance in decision-making.
BCG vaccination induces enhanced frequencies of memory T cells and altered plasma levels of common γc cytokines in elderly individuals
Authors: Kumar Nathella Pavan , Padmapriyadarsini Chandrasekaran , Rajamanickam Anuradha , Bhavani Perumal Kannabiran , Nancy Arul , Jayadeepa Bharathi , Selvaraj Nandhini , Asokan Dinesh , Renji Rachel Mariam , Venkataramani Vijayalakshmi , Tripathy Srikanth , Babu Subash
Published: November 2021

BCG vaccination is known to induce innate immune memory, which confers protection against heterologous infections. However, the effect of BCG vaccination on the conventional adaptive immune cells subsets is not well characterized. We investigated the impact of BCG vaccination on the frequencies of T cell subsets and common gamma c (γc) cytokines in a group of healthy elderly individuals (age 60–80 years) at one month post vaccination as part of our clinical study to examine the effect of BCG on COVID-19. Our results demonstrate that BCG vaccination induced enhanced frequencies of central (p<0.0001) and effector memory (p<0.0001) CD4+ T cells and diminished frequencies of naïve (p<0.0001), transitional memory (p<0.0001), stem cell memory (p = 0.0001) CD4+ T cells and regulatory T cells. In addition, BCG vaccination induced enhanced frequencies of central (p = 0.0008), effector (p<0.0001) and terminal effector memory (p<0.0001) CD8+ T cells and diminished frequencies of naïve (p<0.0001), transitional memory (p<0.0001) and stem cell memory (p = 0.0034) CD8+T cells. BCG vaccination also induced enhanced plasma levels of IL-7 (p<0.0001) and IL-15 (p = 0.0020) but diminished levels of IL-2 (p = 0.0033) and IL-21 (p = 0.0020). Thus, BCG vaccination was associated with enhanced memory T cell subsets as well as memory enhancing γc cytokines in elderly individuals, suggesting its ability to induce non-specific adaptive immune responses.
Surviving SARS and living through COVID-19: Healthcare worker mental health outcomes and insights for coping
Authors: Styra Rima , Hawryluck Laura , Mc Geer Allison , Dimas Michelle , Sheen Jack , Giacobbe Peter , Dattani Neil , Lorello Gianni , Rac Valeria E. , Francis Troy , Wu Peter E. , Luk Wing-Si , Ng Enoch , Nadarajah Jeya , Wingrove Kaila , Gold Wayne L.
Published: November 2021

Objective

Explore how previous work during the 2003 Severe Acute Respiratory Syndrome (SARS) outbreak affects the psychological response of clinical and non-clinical healthcare workers (HCWs) to the current COVID-19 pandemic.

Methods

A cross-sectional, multi-centered hospital online survey of HCWs in the Greater Toronto Area, Canada. Mental health outcomes of HCWs who worked during the COVID-19 pandemic and the SARS outbreak were assessed using Impact of Events—Revised scale (IES-R), Generalized Anxiety Disorder scale (GAD-7), and Patient Health Questionnaire (PHQ-9).

Results

Among 3852 participants, moderate/severe scores for symptoms of post- traumatic stress disorder (PTSD) (50.2%), anxiety (24.6%), and depression (31.5%) were observed among HCWs. Work during the 2003 SARS outbreak was reported by 1116 respondents (29.1%), who had lower scores for symptoms of PTSD (P = .002), anxiety (P < .001), and depression (P < .001) compared to those who had not worked during the SARS outbreak. Multivariable logistic regression analysis showed non-clinical HCWs during this pandemic were at higher risk of anxiety (OR, 1.68; 95% CI, 1.19–2.15, P = .01) and depressive symptoms (OR, 2.03; 95% CI, 1.34–3.07, P < .001). HCWs using sedatives (OR, 2.55; 95% CI, 1.61–4.03, P < .001), those who cared for only 2–5 patients with COVID-19 (OR, 1.59; 95% CI, 1.06–2.38, P = .01), and those who had been in isolation for COVID-19 (OR, 1.36; 95% CI, 0.96–1.93, P = .05), were at higher risk of moderate/severe symptoms of PTSD. In addition, deterioration in sleep was associated with symptoms of PTSD (OR, 4.68, 95% CI, 3.74–6.30, P < .001), anxiety (OR, 3.09, 95% CI, 2.11–4.53, P < .001), and depression (OR 5.07, 95% CI, 3.48–7.39, P < .001).

Conclusion

Psychological distress was observed in both clinical and non-clinical HCWs, with no impact from previous SARS work experience. As the pandemic continues, increasing psychological and team support may decrease the mental health impacts.
Mapping global inputs and impacts from of human sewage in coastal ecosystems
Authors: Tuholske Cascade , Halpern Benjamin S. , Blasco Gordon , Villasenor Juan Carlos , Frazier Melanie , Caylor Kelly
Published: November 2021

Coastal marine ecosystems face a host of pressures from both offshore and land-based human activity. Research on terrestrial threats to coastal ecosystems has primarily focused on agricultural runoff, specifically showcasing how fertilizers and livestock waste create coastal eutrophication, harmful algae blooms, or hypoxic or anoxic zones. These impacts not only harm coastal species and ecosystems but also impact human health and economic activities. Few studies have assessed impacts of human wastewater on coastal ecosystems and community health. As such, we lack a comprehensive, fine-resolution, global assessment of human sewage inputs that captures both pathogens and nutrient flows to coastal waters and the potential impacts on coastal ecosystems. To address this gap, we use a new high-resolution geospatial model to measure and map nitrogen (N) and pathogen—fecal indicator organisms (FIO)—inputs from human sewage for ~135,000 watersheds globally. Because solutions depend on the source, we separate nitrogen and pathogen inputs from sewer, septic, and direct inputs. Our model indicates that wastewater adds 6.2Tg nitrogen into coastal waters, which is approximately 40% of total nitrogen from agriculture. Of total wastewater N, 63% (3.9Tg N) comes from sewered systems, 5% (0.3Tg N) from septic, and 32% (2.0Tg N) from direct input. We find that just 25 watersheds contribute nearly half of all wastewater N, but wastewater impacts most coastlines globally, with sewered, septic, and untreated wastewater inputs varying greatly across watersheds and by country. Importantly, model results find that 58% of coral and 88% of seagrass beds are exposed to wastewater N input. Across watersheds, N and FIO inputs are generally correlated. However, our model identifies important fine-grained spatial heterogeneity that highlight potential tradeoffs and synergies essential for management actions. Reducing impacts of nitrogen and pathogens on coastal ecosystems requires a greater focus on where wastewater inputs vary across the planet. Researchers and practitioners can also overlay these global, high resolution, wastewater input maps with maps describing the distribution of habitats and species, including humans, to determine the where the impacts of wastewater pressures are highest. This will help prioritize conservation efforts.Without such information, coastal ecosystems and the human communities that depend on them will remain imperiled.
Sylvia Townsend Warner and Peter Pears: Loss and Friendship
Authors: Mutti Lynn
Published: November 2021

This article describes the friendship between Sylvia Townsend Warner, Peter Pears and Benjamin Britten in the 1970s. It draws on previously unpublished correspondence held at the Britten-Pears Archive and the Sylvia Townsend Warner and Valentine Ackland Archive. It describes the role that John Craske’s paintings played in establishing the connection between Warner and Pears, details some visits and covers Britten’s illness and death. The article also describes the concert in Warner’s honour planned by Pears and given in Aldeburgh in July 1977.
A mulher (na) política brasileira em perfis jornalísticos no Instagram
Authors: Morais Martins Juliana
Published: November 2021

Este artigo analisa os discursos sobre mulheres atuantes na esfera política no Brasil no Instagram. Assim, tem-se como pergunta de pesquisa: “Como se constitui o discurso sobre a mulher na política brasileira em postagens de perfis jornalísticos no Instagram?”. Para isto, buscou-se analisar as postagens veiculadas em três perfis presentes no SRS Instagram, a saber: O Antagonista, Folha de S. Paulo e a revista Carta Capital. Tem-se como linha teórico-metodológica a Análise do Discurso francesa (AD) com base nos estudos do filósofo Michel Foucault, notadamente as noções de discurso e enunciado. Para tanto, busca-se investigar as maneiras pelas quais o discurso sobre a mulher (na) política se revela e é construído em veículos jornalísticos de diferentes linhas políticas no Brasil, dentro do período pré-eleitoral de 2018. Por meio da análise do corpus, observaram-se as seguintes regularidades discursivas: i) a mulher ligada ao homem – a noção de família; ii) a invisibilidade da mulher (na) política. Nota-se a baixa reincidência de postagens que colocam a mulher em foco, como ponto central das matérias veiculadas no Instagram, bem como a construção de um vínculo dessa mulher com a figura masculina no momento em que esta adentra no campo político.
“Quer ser, amiga linda, uma mulher de verdade?”
Authors: Barreto Santana Daniela , Carneiro Borges Carla Luzia
Published: November 2021

Neste artigo, analisa-se, numa perspectiva de Estudos Discursivos Foucaultianos, o discurso sobre a Mulher Magnética, o qual é visto, aqui, como uma reatualização de discursos que circularam em outras temporalidades e que colocam a mulher como submissa ao homem, e o processo de subjetivação da mulher de hoje. Para tanto, toma-se como materialidades discursivas, vídeos públicos do canal de Youtube Mulher Magnética (2015-2019), utilizando o método arqueológico proposto por Foucault. Também fazemos uma leitura arqueológica de outras materialidades nas quais determinados discursos sobre a mulher têm visibilidade, a saber: passagens bíblicas e matérias da revista feminina Jornal das Moças (1950-1960). Observou-se que tais discursividades, apesar de conclamarem as mulheres a ocuparem uma nova posição, são, na verdade, uma reatualização de discursos que circularam em outras temporalidades e que colocam a mulher em um lugar subalterno em relação ao homem.
Word-Formation Process on COVID-19 Related Terms as Japanese Language Variation
Authors: Syartanti Nadya Inda
Published: November 2021

This research aims to identify the types of vocabulary in Japanese, to explore the word-formation process, and to analyse the function of COVID-19 related terms conveyed by various content creators on YouTube channels, from Japan and Indonesia. The seven YouTube channel accounts are Aki no Sora (Indonesia), po.n.go_id or Pocket Nihongo (Indonesia), Sakura Pinku (Indonesia), Wagomu (Indonesia), Omoshiroi Nihongo (Japan), Japanese Ammo with Misa (Japan), and Coto Academy (Japan that used as the data source. Data were collected using the observation method and analysed by the distribution method. The results showed that the COVID-19 related terms are dominated by the type of vocabulary kango as the form or type of vocabulary that is most widely used in matching the COVID-19 related term. Among all word-formation processes, the COVID-19 terms in Japanese identified as borrowing, compounding, and multiple processes. However, the multiple word-formation processes are dominated on COVID-19 terms in Japanese. It related to the domination of the type of kango used. From that, there are multiple functions that are included in COVID-19 terms in Japanese, namely disease information, preventive action, symptom, and announcement. Therefore, this research can be contributed to data analysis, which used morphological analysis in Japanese terms.