bluuebunny/crossref_metadata_2025 huggingface dataset:
CARBON NANOCOMPOSITE COATED TEXTILE-BASED SENSOR: SENSING MECHANISM AND DURABILITY
Authors: CHAUDHARI AMIT , DOSHI SAGAR , WEISS MADISON , SUNG DAE HAN , THOSTESON ERIK
Published: November 2021

Carbon nanotube (CNT) composite films are deposited onto stretchable knit fabrics using electrophoretic deposition (EPD) and dip-coating techniques, which are industrially scalable processes for producing future wearable sensors. The deposited CNTs create an electrically conductive nanocomposite film on the surface of the fibers. These nanocomposite coated fabrics exhibit piezoresistive properties; under mechanical deformation/stretching, a large change in the electrical resistance is observed. Polyethyleneimine (PEI) functionalized carbon nanotubes deposited using EPD create a uniform, extremely thin porous coating on the fiber. Initial results show ultrahigh sensitivity of the carbon nanotube coated fabric when tested on elbow/knee to detect range of motion. The sensitivity of these sensors is exceptionally high when compared to a typical carbon nanotube-based polymer nanocomposite. The nanocomposite coating does not affect fabric's breathability or flexibility, making the sensor comfortable to wear. Because of these unique properties, tremendous potential exists for their use in functional/smart garments. Changes in electrical resistance for these fabrics are influenced by a combination of electron tunneling between the carbon nanotubes and the microstructure of the fabric. To investigate and characterize the unique sensing mechanism, the nanotube coated knit fabric's electromechanical response is studied at different length scales, from individual yarns to fabric levels. For applications in wearable sensors, the durability of the nanotube coating on the fabric is critical for repeatable and reliable sensing response. Durability testing of the sensing fabric for washing loads was conducted to study the nanotube coating's robustness. CNT coating's adhesion quality is evaluated based on the weight loss in the specimen and loss in electrical conductivity in each wash cycle. This research addresses the potential of these sensors for functional/smart garments by examining the underlying mechanism of the sensor response and the durability of the carbon nanotube coating.
SYNERGISTIC EFFECTS OF PLASMA POLYMERIZATION AND COVALENT SURFACE MODIFICATION OF CARBON FIBERS
Authors: EYCKENS DANIEL J. , SOULSBY LACHLAN , STOJCEVSKI FILIP , WICKRAMASINGHA ATHULYA , HENDERSON LUKE C.
Published: November 2021

This work demonstrates the efficacy in performing an electrochemical pretreatment on carbon fibres to improve the effect of plasma polymerization of acrylic acid on these surfaces. Modified samples demonstrated improve physical properties including tensile strength and Young’s modulus, as well as an increase in composite performance as measured by the interfacial shear strength. The electrochemical pretreatment was shown to enhance the advantages observed when coating fibres using plasma polymerization.
THE EFFECTS OF STRUCTURAL-INDUCED DEFORMATION ON THE RESONANCE OF PATCH ANTENNAS
Authors: NICHOLSON KELVIN , WANG JOHN , HEALEY ROWAN , LYNCH TAYLOR , PATNIOTIS JOEL , CHIU WINGKONG
Published: November 2021

Conformal Loadbearing Antenna Structures (CLAS) take advantage of a combination of structural and electromagnetic functions. CLAS have been developed as an advanced replacement for conventional antennas (such as blades, wires and dishes) to improve the structural efficiency, as well as the electromagnetic and aerodynamic performance of a platform. The CLAS concept permits the direct integration of microwave radiating elements in the structural skin of a platform. Therefore, the antenna will be subjected to structural loading and will deform accordingly. The effects of these structural-induced deformations on the resonant frequency of the antenna will be reported in this paper. This paper will investigate the performance of a carbon veil patch antenna when it is subject to static in-plane. The work presented will include the effects of in-plane loading on the resonant behavior of the patch antenna when the carbon veil is fully bonded and when it is disbonded by the parent structure. This paper will also discuss the effects of substrate delamination on the RF response of the patch antenna. The RF characteristics of the antenna will be modelled using ANSYS High Frequency Structure Simulator (HFSS).
LOW THERMAL CONDUCTIVITY COMPOSITE SKIN MATERIALS
Authors: SCHOENHOLTZ STEVE , GAVRIN ARTHUR , CHEN CHENGGANG
Published: November 2021

Triton Systems, Inc. and our academic partner University of Dayton Research Institute (UDRI) developed and demonstrated a lightweight, affordable composite heat shield sandwich panel for aerospace applications capable of protecting an underlying Polymer Matrix Composite (PMC) sandwich panel from 500℉ external impingement. Our design outperforms the incumbent heat shield, a bolt-on metallic sheet with an air gap, in both thermal protection (15% lower skin surface temperature) and weight (40% lighter) at an equivalent thickness (about 0.3”). Our panel has very low thermal conductivity (0.08 W/mK) but is also impact resistant, strong (~300 psi flatwise tensile strength), and tolerant to typical aerospace environmental conditions. Additionally, we demonstrated that our design could be produced as a curved panel configuration to match vehicle outer mold lines (OML’s). Now at Technology Readiness Level (TRL) 4, Triton’s panel design is ready to move to the next stage of development which we envision to be additional proof-of-concept testing including chemical and additional environmental exposure, cold exposure, thermal shock, and vibration as we scale up to a larger 4’x8’ panel. STEVE SCHOENHOLTZ
IMPACT DAMAGE AND INJECTION REPAIR STRENGTH RESTORATION
Authors: MASSEY JUSTIN , ROMASKO BARRETT , KIM HYONNY
Published: November 2021

Impact damage to composite structures can lead to a range of damage modes. Of interest is modest damage composed of delaminations less than 50 mm in size, and no visible impact-side fiber breakage. While resin injection is a current-practice repair technique that can be used to address these damage modes in a manner that is much less invasive than bonded scarf patch repair, the injection technique is not currently credited as one restoring strength back to laminate. Issues of quantifying the removal of any internal contamination, assessing degree of resin fill, and demonstration of how much strength is restored are being addressed within the scope of this research activity. Resin injection will be conducted and the resulting strength restoration assessed in local fracture tests (end-notch flexure). The formation of actual impact damage morphologies, namely multiple planes of delamination interconnected with matrix cracks, is a critical aspect of this problem. Three 25-ply composite panel types having varying percentage of 0o fiber content have been impacted under low velocity at a range of energy levels. Resulting force vs. time and ultrasonic mapping of damage extent. Damage produced by such impacts will be used in subsequent injection repair studies. Intentional contamination will be introduced, and then removal will be achieved via injected solvents and atmospheric plasma, with monitoring of contaminant presence achieved by in-line quantitative chemical analysis.
GLOBAL-LOCAL PROGRESSIVE DAMAGE ANALYSIS OF COMPOSITE LAMINATES USING LAYER-WISE HIGHER-ORDER STRUCTURAL MODELSv
Authors: NAGARAJ MANISH H. , CARRERA ERASMO , PETROLO MARCO
Published: November 2021

The objective of the current work is to develop a global-local framework for the progressive damage analysis of composite laminated structures. The technique involves two sequential analyses—an initial low-fidelity 3D-FE based linear analysis of the global structure, followed by the local nonlinear analysis of critical regions where damage is likely to occur. The numerical models used for the local analysis are developed using higher-order layer-wise structural theories obtained via the Carrera Unified Formulation. Composite damage is modelled using the CODAM2 model based on continuum damage mechanics, and the nonlinear problem is solved using explicit time integration schemes. Preliminary assessments are carried out to validate the proposed global-local framework by considering open-hole tensile specimens of quasi-isotropic composite laminates. Both full-scale CUF models and the proposed global-local approach are used to predict the tensile strength of the specimen. It is shown that the obtained results are in good agreement with experiment data, thus validating the framework, and a multi-fold improvement in computational time is demonstrated.
NUMERICAL PREDICTION OF STIFFNESS DEGRADATION OF THIN-PLY CFRP LAMINATES UNDER FATIGUE LOADING
Authors: AOKI RYOMA , HIGUCHI RYO , YOKOZEKI TOMOHIRO
Published: November 2021

This study aims to conduct a fatigue simulation for predicting the stiffness degradation of thin-ply composite laminates with several ply thicknesses. For the simulation, a fatigue evolution model of intra-laminar damage in thin-ply composite laminates considering the effect of ply thickness was proposed. The intra-laminar damage evolution was modeled using the continuum damage mechanics model and the static and fatigue evolution law were formulated by relating the transverse crack density to the damage variable. The finite element simulation using the proposed model was conducted to predict the stiffness degradation of the laminates as a function of the number of loading cycles. The simulation results show that the experimental data can be reproduced by using the proposed fatigue model.
COMPUTATIONAL INVESTIGATION OF ENERGY DISSIPATION THROUGH PROGRESSIVE FAILURE IN TAILORED COMPOSITE STRUCTURES VIA EXPLICIT FINITE ELEMENT ANALYSIS
Authors: SRINIVAS ANIRUDH , DANCILA D. STEFAN
Published: November 2021

A composite material tailoring concept for progressive failure under tensile loading has been previously developed, modeled, and experimentally validated by the second author and his collaborators. The concept relies upon a sequential failure process induced in a structure of series connection of parallel redundant load path elements of tailored length and strength. The resulting yield-type response under tensile loading is characterized by an increased energy dissipation compared to a reference conventional structural element of nominally identical length and crosssectional area, and of the same composite material. In this work, this composite tailoring concept is computationally investigated for IM7-8552 composite material using a dynamic, explicit finite element analysis in Abaqus. The approach offers the advantage of capturing the stress wave propagation within the model throughout the dynamic failure sequence, thereby providing a better understanding of the failure progression and the energy dissipation mechanisms at work. In this study, progressive failure of the tailored composite structure is modeled and analyzed for different configurations of lengths and widths. Model predictions are illustrated for and compared with selected tailoring configurations from the literature. Developing an explicit finite element approach for analyzing the tailoring concept opens the door to characterizing a wide variety of related, more complex configurations for which analytical solutions do not yet exist or may not even be feasible, and/or for which experimental results may be difficult or overly expensive to obtain.
A MULTIFUNCTIONAL AND RECONFIGURABLE MICROVASCULAR COMPOSITE
Authors: DEVI URMI , PEJMAN REZA , PHILLIPS ZACHARY J. , NAKSHATRALA KALYANA B. , NAJAFI AHMAD R. , SCHAB KURT R. , PATRICK JASON F.
Published: November 2021

Fiber-reinforced polymer (FRP) composites, consisting of stiff/strong fibers embedded within a continuous matrix, are a lightweight structural platform supporting an array of modern applications. Bioinspired vascularization of fiber-composites can augment existing performance with dynamic functionalities via liquid infiltration of the internal micro-fluidic network. Some vascular-enabled capabilities include self-healing to repair delamination damage and active-cooling to prevent thermal degradation. While such attributes have been demonstrated in separate platforms, research investigations that combine functionalities within a single composite have been limited. Here we provide a recent study that highlights a promising pathway for achieving both multifunctional, and reconfigurable behavior in microvascular FRP composites. Specifically, we detail the ability to regulate temperature and modulate electromagnetic signature via fluid substitution within the same serpentine vasculature. Varying microchannel density alters both active-cooling efficiency by water circulation and polarized radio-frequency wave reflection by liquid metal infiltration. We control these bulk property pluralities by widespread vascularization, while minimizing impact on structural performance, and decode the effects of micro-vascular topology on macromechanical behavior. Our in-depth experimental and computational investigation provides a new benchmark for future design optimization and real-world translation of multifunctional and adaptive microvascular composites.
CYCLIC THERMORESISTIVITY OF CARBON NANOTUBE YARN/SILICONE RUBBER MATRIX MONOFILAMENT COMPOSITES
Authors: TAYYARIAN TANNAZ , RODRIGUEZ-UICAB OMAR , AFREEN TANJEE , ABOT JANDRO L.
Published: November 2021

Thermoresistive characterization of CNTY monofilament composites was investigated by using the electrical response of a single carbon nanotube yarn (CNTY) embedded in a silicone polymer forming monofilament composites. Two room temperature vulcanizing (RTV) silicone rubbers with different polymerization mechanisms (OOMOO and Ecoflex) were used as the polymeric matrices. Continuous heating-cooling thermal cycling ranging from room temperature (RT~25 °C) to 80 °C was performed in order to determine the thermoresistive sensitivity, hysteresis and residual fractional change in electrical resistance after each cycle. The thermoresistive response was nearly linear, with negative temperature coefficient of resistance at the heating and cooling zones for CNTY/ OOMOO and CNTY/Ecoflex specimens. The average value of this coefficient at the heating and cooling sections was - 6.65×10-4 °C-1 for CNTY/OOMOO and -7.35×10-4 °C-1 for CNTY/Ecoflex. Both monofilament composites showed a negligible negative residual electrical resistance with an average value of ~ -0.08% for CNTY/OOMOO and ~ -0.20% for CNTY/Ecoflex after each cycle. The hysteresis yielded ~19.3% for CNTY/OOMOO and ~29.2% in CNTY/Ecoflex after each cycle. Therefore, the curing kinetics and viscosity play a paramount role in the electrical response of the CNTY immersed into these rubbery matrices.
MICRO-CT IMAGE-BASED RECONSTRUCTION MODEL FOR FAILURE ANALYSIS OF SHEET MOLDING COMPOUND (SMC) COMPOSITES
Authors: LIM HYOUNG JUN , CHOI HO-IL , YUN GUN JIN
Published: November 2021

This research provides a multiscale framework of failure analysis for carbon-fiber sheet molding compound (CF-SMC) through a bundle packing reconstruction algorithm and material constitutive modeling, respectively. SMC composites have attracted the attention of many industries due to their high strength-to-weight ratio. However, depending on the speed and pressure in the manufacturing process, the spatially different flow patterns of fiber bundles lead to show inhomogeneous mechanical performance. This is because the location and orientation of fiber bundles in SMC composites have a significant role in mechanical behavior. Therefore, it is crucial to understand the effects of these parameters on mechanical behavior. Therefore, in this study, micro-CT imaging is performed to accurately determine SMC composites' internal geometry. The orientation and location of fiber bundles are statistically expressed as cumulative distribution function (CDF). Using these distributions as input, a mesoscale representative volume element (RVE) is constructed through a bundle packing reconstruction algorithm based on the random sequential adsorption (RSA) method. Furthermore, to demonstrate failure analysis of the SMC composites, constitutive modeling of each constituent is established. Consequently, the change of mechanical behavior is estimated under different manufacturing conditions.
MULTISCALE ANALYSIS OF THERMO-MECHANICAL BEHAVIOR OF BORON NITRIDE-REINFORCED EPOXY NANOCOMPOSITES
Authors: ALUKO OLANREWAJU , GOWTHAM S. , PINEDA EVAN J. , ODEGARD GREGORY M.
Published: November 2021

The effect of size, shape, morphology, and arrangement of micro constituents of Boron Nitrite (BN) nanoplatelet/epoxy composites on their properties were investigated using a multi scale approach that includes Molecular Dynamics (MD) and micromechanics. The thermo-mechanical properties of the composites were evaluated using molecular theory and the analysis showed that the elastic constants of BN/epoxy composites were not severely affected by temperature. Also, the micromechanical analysis of Generalized Method of Cells (GMC) was utilized at higher length scale to evaluate elastic properties of the composites, for different geometries and arrangements of micro constituents. The predicted results of the analysis showed that the size, aspect ratios, morphology, and the arrangements of inclusions in BN/epoxy nanocomposites all have remarkable effect on the mechanical performances of the material systems.
FIBER REINFORCED ASPHALT
Authors: COY RYAN , CONSARNAU RAFAEL GOMEZ , HOLMES IAN , WHISLER DANIEL
Published: November 2021

Asphalt can be considered a particulate composite with almost no tensile strength, that is, the only physical link between the matrix (bitumen) and the particles (gravel) is the cohesive strength of the bond itself and the aggregate simply breaks away from the binder under any number of tension-based loads such as earth shifts, heavy loads, and even moisture. Over the course of a few months, these breaks lead to larger cracks, potholes, and damaged entire road sections that require significant investment much earlier than the expected 15-year lifecycle. Increasing the strength and modulus of asphalt can improve its durability, extend its lifespan, and reduce its maintenance costs. However, as most asphalt is usually recycled during rehabilitation, improving strength cannot come at the expense of the existing infrastructure support system, i.e., materials and technologies should be compatible with road resurfacing equipment and practices. Short composite fibers have high modulus and strength but are easily broken up by road milling machines, making them ideal candidates to mix into the asphalt during rehabilitation. Additionally, by deliberately limiting the fiber size, this will have a major ancillary benefit for the environment: allowing the use of off-fall composite scraps from the manufacturing sectors that are often chopped and relegated to landfills. This investigation examines the material behavior from both experimental and numerical perspective on the inclusion of short fibers for reinforcing asphalt, creating a dual fiber and particle composite material system. Asphalt by its very nature is a relatively soft material with high strains until failure under some conditions, and brittle under others, making this a complex material system combining both hyperelastic and elastic-brittle response. Validation studies are examined for this unique material under various quasi-static to dynamic loading rates to create a material system for extended finite element analysis in improved infrastructure designs.
CLOSED-FORM J-INTEGRAL AND ITS APPLICATIONS FOR MEASUREMENT OF MODE I INTERLAMINAR FRACTURE TOUGHNESS OF COMPOSITES
Authors: XU WU , DING JIANCAN
Published: November 2021

Due to the interlaminar properties of composites are low, delamination is one of the major failure modes. It threatens the safety of composite structure subjected to out-of-plane static and especially impact loadings. High interlaminar fracture toughness is demanded in the society where composite structures are widely used. However, for tough material, large deformation may occur in the determination of the interlaminar fracture toughness when using the double cantilever beam (DCB) test. Therefore, accurate determination of the fracture toughness of tough material and dynamic loading is very challenging under large deformation. J-integral is an important parameter in fracture mechanics. It’s equivalent to energy release rate under monotonic loading and widely used in the determination of interlaminar fracture toughness of composites. In this paper, it is used to determine the fracture toughness for composite DCB under large deformation and wedge-insert double cantilever beam (WDCB) test, which is widely used to determine the dynamic interlaminar fracture toughness. Exact and closed form nonlinear J-integrals are derived for the largely deformed DCB and WDCB. Compared with the alternative data reduction methods for determining interlaminar fracture toughness, the J- integral method is more accurate. In addition, the J-integral method is simple and promising, since it is unnecessary to measure the crack length in the tests.
VIBRATIONS OF PRESTRESSED VARIABLE STIFFNESS COMPOSITE AEROSPACE STRUCTURES BY RITZ APPROACH
Authors: SCIASCIA GIUSEPPE , OLIVERI VINCENZO , WEAVER PAUL
Published: November 2021

With the introduction of the variable stiffness concept, the design space for highperformance lightweight composite structures has expanded significantly. A larger design space, in particular, allows designers to find more effective solutions with higher overall stiffness and fundamental frequency when considering prestressed dynamically excited aerospace components. In this context, an efficient and versatile Ritz method for the transient analysis of prestressed variable stiffness laminated doubly-curved shell structures is presented. The considered theoretical framework is the first-order shear deformation theory without further assumptions on the shallowness or on the thinness of the structure. A rational Bézier surface representation is adopted for the description of the shell allowing general orthogonal surfaces to be represented. General stacking sequences are considered and the unknown displacement field is approximated by Legendre orthogonal polynomials. Stiffened variable angle tow shell structures are modelled as an assembly of shell-like domains and penalty techniques are used to enforce the displacement continuity of the assembled multidomain structure and the kinematical boundary conditions. For the transient analysis of prestressed variable stiffness structures, classical Rayleigh damping is considered and solutions are obtained through the Newmark integration scheme. The proposed approach is validated by comparison with literature and finite elements results and original solutions are presented for prestressed free and forced vibrations of VS stiffened shell structure, proving the ability of the present method in dealing with the analysis of complex aerospace structures.
FAILURE OF CFRP AND TITANIUM TUBULAR ADHESIVE LAP JOINTS AT EXTREME TEMPERATURES
Authors: KAISER ISAIAH , ZHANG CHAO , TAN K. T.
Published: November 2021

In this work, carbon fiber reinforced polymer and titanium adhesive tubular lap- joints (TLJs) at cold-temperature, room-temperature, and elevated-temperature are studied. Finite element analysis is employed to investigate the competing damage mechanisms within the TLJs. The relationship between the joint strength and adhesive bondline length is also determined. X-ray micro-computed tomography (μCT) technique is utilized to analyze composite damage characteristics; whilst statistical design of experiment (DoE) approach is used to understand the interaction between bondline length and temperature on the mechanical performance of TLJs. Results show a mixed-mode failure region at elevated-temperatures, causing the TLJ to fail by either interlaminar shear or titanium net-section fracture. Results further reveal that deformation within the titanium creates shear stresses on the composite tube, leading to the initiation, propagation, and coalescence of delamination. Employing numerical, experimental, and statistical techniques, this works provides insights into the parameters and mechanisms affecting the behavior and failure of adhesive TLJs at extreme temperature conditions.
The role of hotel architecture in shaping the city’s image
Authors: Strumiłło Krystyna
Published: November 2021

The elements of the environment are characterized by variability. The structure of the city is also a subject to constant structural, social and material transformations.

Objects in the city can play significant role for urban landscape. In recent years, it can be observed that the architecture of hotels in cities is becoming more and more unique. After years of building similar hotel facilities, architects began to create more and more original forms that attract the attention of passers-by and are remembered. The importance of individual places in the hierarchy of these space is also changing. Hotels are elements thatbuild the image of cities, often becoming their visual dominant. This applies to creating a sculpture in a space that catch attention with its form and play of colors.

The aim of the article is to show, on the example of selected projects, how hotel buildings can shape urban images. The research method is based on the analysis of selected objects and showing their role in shaping the image of the city. The concept of the hotel influences the building of identity. The form of the hotel, the functionality, the materials, and their combination, create the semantic experience for observer. The hotel becomes a ‘story’ narrative that gives visitors or pedestrians a personal feeling of reading architecture.

According to Kevin Lynch (1960:8), the external image we perceive can be analyzed by combining three factors: identity, structure and meaning. Identity is identifying an object, distinguishing it from others, making it exclusive. Thus, fragments of space of greater importance are created in the city, which are shaped in terms of public utility. These areas, having greater value, are also of greater prestige for the city. They add as well the aesthetic energy to the city.
Open-Air Łódź Sculpture Gallery and Its Influence on the City’s Aesthetics in 1972–1978
Authors: Nowakowska Maria
Published: November 2021

The aim of the paper is to outline the circumstances of the establishment of the Łódź Sculpture Gallery in Rubinstein’s Alley (formerly: Aleja ZMP) and its impact on the aesthetics of Łódź.

Despite the city’s history dating back to the beginning of the 15th century, the first fully-fledged sculpture in public space appeared only in 1912. By the beginning of World War II, the number of sculptures increased to a dozen or so, but all of those works were destroyed by the Germans in the first years of the occupation.

In the period 1945–1970, two monuments and a dozen or so smaller forms appeared. The sculptural face of the city was changed only by the Łódź Sculpture Gallery, which focused on the most important issues of post-war town planning, politics, artistic trends, and social needs. Despite its short period of operation (1972–1978), its effects are still visible almost everywhere in Łódź. Never before and never after has the medium of sculpture been aestheticised on such a scale in the city.

The memory of this place and several dozen sculptures (and of their creators) has almost faded away. Currently, activities are under way to restore the Łódź Sculpture Gallery to its due position in the history of the city and to continue its activities in the same place.
Optimization of optical waveguide antennas for directive emission of light
Authors: Farheen H. , Leuteritz T. , Linden S. , Myroshnychenko V. , Förstner J.
Published: November 2021

Optical traveling wave antennas offer unique opportunities to control and selectively guide light into a specific direction, which renders them excellent candidates for optical communication and sensing. These applications require state-of-the-art engineering to reach optimized functionalities such as high directivity and radiation efficiency, low sidelobe levels, broadband and tunable capabilities, and compact design. In this work, we report on the numerical optimization of the directivity of optical traveling wave antennas made from low-loss dielectric materials using full-wave numerical simulations in conjunction with the particle swarm optimization algorithm. The antennas are composed of a reflector and a director deposited on a glass substrate, and an emitter placed in the feed gap between them serves as an internal source of excitation. In particular, we analyze antennas with rectangular- and horn-shaped directors made of either hafnium dioxide or silicon. The optimized antennas produce highly directional emissions due to the presence of two dominant guided TE modes in the director in addition to leaky modes. These guided modes dominate the far-field emission pattern and govern the direction of the main lobe emission, which predominately originates from the end facet of the director. Our work also provides a comprehensive analysis of the modes, radiation patterns, parametric influences, and bandwidths of the antennas, which highlights their robust nature.
Multiple input/output waveguides light-induced by a single Bessel beam for all-optical interconnects
Authors: Chai Yue , Bouldja Nacera , Marsal Nicolas , Wolfersberger Delphine
Published: November 2021

We numerically study photo-induced waveguides using a single Bessel beam in a photorefractive (PR) medium. Under self-focusing nonlinearity, we demonstrate the possibility for creating complex waveguiding structures with multiple input/output channels. The truncation of the incoming Bessel beam, the nonlinearity of the PR medium, the light intensity, and the order and the size of the Bessel beam are the key parameters for achieving different configurations with high guiding efficiencies. As such, not only classical X or Y couplers but also more complex structures can be generated with up to 7 identified inputs/outputs. These results provide large opportunities for all-optical interconnects.
Surface plasmon resonance chemical sensor composed of a microstructured optical fiber for the detection of an ultra-wide refractive index range and gas-liquid pollutants
Authors: Liu Wei , Shi Ying , Yi Zao , Liu Chao , Wang Famei , Li Xianli , Lv Jingwei , Yang Lin , Chu Paul K.
Published: November 2021

A surface plasmon resonance (SPR) chemical sensor comprising microstructured optical fiber (MOF) is designed for refractive index (RI) sensing in the visible to near-infrared (0.42-1.60 µm) region (NIR) as well as detection of gas-liquid pollutants. To realize mode coupling and facilitate manufacturing, gold with inert and plasmonic properties and an analyte sensing layer are introduced to the external surface of the MOF. The sensor is analyzed by the full-vector finite element method (FEM) and the wavelength and amplitude interrogation methods are adopted to evaluate the sensing characteristics. Our analysis reveals a maximum wavelength sensitivity (WS) of 15,000 nm/RIU, amplitude sensitivity (AS) of 1,603.37 RIU-1, and resolution (R) of 6.67×10−6 RIU in the determination of analyte RIs spanning an ultra-wide range between 1.00 and 1.45. Furthermore, the figure of merit (FOM) and signal-to-noise ratio (SNR) of the sensor are 295.01 RIU−1 and 2.95, respectively. On account of its simple structure, low cost, and industrial compatibility, this multi-functional sensor has tremendous potential in the chemical industry, environmental monitoring, and safety control such as harmful gas monitoring, industrial wastewater and domestic sewage detection.
Impact of the precursor gas ratio on dispersion engineering of broadband silicon nitride microresonator frequency combs
Authors: Moille Gregory , Westly Daron , Simelgor Gregory , Srinivasan Kartik
Published: November 2021

Microresonator frequency combs, or microcombs, have gained wide appeal for their rich nonlinear physics and wide range of applications. Stoichiometric silicon nitride films grown via low-pressure chemical vapor deposition (LPCVD), in particular, are widely used in chip-integrated Kerr microcombs. Critical to such devices is the ability to control the microresonator dispersion, which has contributions from both material refractive index dispersion and geometric confinement. Here, we show that modifications to the ratio of the gaseous precursors in LPCVD growth have a significant impact on material dispersion and hence the overall microresonator dispersion. In contrast to the many efforts focused on comparisons between Si-rich films and stoichiometric (

S

i

3

N

4

) films, here, we focus on films whose precursor gas ratios should nominally place them in the stoichiometric regime. We further show that microresonator geometric dispersion can be tuned to compensate for changes in the material dispersion.
Charting host-microbe co-metabolism in skin aging and application to metagenomics data
Authors: Alkema Wynand , Boekhorst Jos , Eijlander Robyn T. , Schnittger Steve , De Gruyter Fini , Lukovac Sabina , Schilling Kurt , Kortman Guus A. M.
Published: November 2021

During aging of human skin, a number of intrinsic and extrinsic factors cause the alteration of the skin’s structure, function and cutaneous physiology. Many studies have investigated the influence of the skin microbiome on these alterations, but the molecular mechanisms that dictate the interplay between these factors and the skin microbiome are still not fully understood. To obtain more insight into the connection between the skin microbiome and the human physiological processes involved in skin aging, we performed a systematic study on interconnected pathways of human and bacterial metabolic processes that are known to play a role in skin aging. The bacterial genes in these pathways were subsequently used to create Hidden Markov Models (HMMs), which were applied to screen for presence of defined functionalities in both genomic and metagenomic datasets of skin-associated bacteria. These models were further applied on 16S rRNA gene sequencing data from skin microbiota samples derived from female volunteers of two different age groups (25–28 years (‘young’) and 59–68 years (‘old’)). The results show that the main bacterial pathways associated with aging skin are those involved in the production of pigmentation intermediates, fatty acids and ceramides. This study furthermore provides evidence for a relation between skin aging and bacterial enzymes involved in protein glycation. Taken together, the results and insights described in this paper provide new leads for intervening with bacterial processes that are associated with aging of human skin.
Women and men in senior management – Key recurring themes and questions
Authors: Dunavölgyi Mária
Published: November 2021

Nowadays, questions on the low female participation in senior management are considered and analysed not only within the academic community, but are also discussed and debated by politicians and business representatives. The purpose of this article is to provide an overview of the key issues and possible approaches to the topic. In the first part, the author focuses on leadership styles: contemporary issues, theoretical considerations and empirical research results. Based on the findings that support the comparative advantages of diverse leadership teams, the author deals with the recommendations on the optimal gender composition of senior management teams. As empirical data are not in line with the recommendations, the author draws attention to the challenges related to talent recognition in the case of potential women leaders and the unequal opportunities in manager selection, such as important factors of low female representation in senior management. Academic articles on terminology, alternative values, special contributions, meritocracy and the social and cultural aspects of unequal opportunities are covered in order to highlight the main factors of the topics discussed.
Assessment of Duodenal Intraepithelial Lymphocyte Composition (Lymphogram) for Accurate and Prompt Diagnosis of Celiac Disease in Pediatric Patients
Authors: Camarero Cristina , De Andrés Ana , García-Hoz Carlota , Roldán Belén , Muriel Alfonso , León Francisco , Roy Garbiñe
Published: November 2021

INTRODUCTION:

Quantitative and phenotypic analyses of duodenal intraepithelial lymphocytes (IELs) by flow cytometry (IEL lymphogram) confer specificity and enable the diagnosis even in unconventional presentations of celiac disease (CD). To evaluate the validity of the IEL lymphograms in the pediatric population for new insights into their use as biomarkers in the natural history of CD.

METHODS:

We retrospectively included 1,211 children (602 with active CD, 92 on a gluten-free diet, 47 with potential CD, and 470 nonceliac controls) who required duodenal biopsies in this study. The cutoff values for IEL subsets were established to calculate the probability of disease according to the lymphogram.

RESULTS:

A celiac lymphogram (a ≥15% increase in gamma-delta T-cell receptor IELs and a simultaneous ≤6% decrease in CD3 surface-negative [sCD3−]) IELs was strongly associated with the diagnosis of active CD, which was present in 89.7% of the confirmed patients. The remaining 10% of the celiac patients had a partial celiac lymphogram (≥15% increase gamma-delta T-cell receptor IELs or ≤6% decrease in sCD3− IELs), with lower diagnostic certainty. On a gluten-free diet, nearly 20% of the patients were indistinguishable from nonceliac subjects based on the lymphogram. In potential CD, a decrease in sCD3− IELs was a risk marker of progression to villous atrophy and a diagnosis of active CD.

DISCUSSION:

If a biopsy is clinically indicated, the IEL lymphogram adds specificity to the histological findings, reducing diagnostic delays and misdiagnoses. The lymphogram is useful for monitoring the natural progression of the disease and predicting the transition from potential celiac to overt CD.
Superbohaterki w kinie przed powstaniem Marvel Cinematic Universe. Historia adaptacji kobiecych kostiumów superbohaterskich
Authors: Srul Klaudia
Published: November 2021

The article focuses on changes within superhero comic book movie adaptations from 1941 (Adventures of Captain Marvel premiere) to 2008 (the creation of Marvel Cinematic Universe) in the aspect of designing female characters’ costumes. Author’s refelections are based on the article From the Top of the Cowl to the Tip of the Cape. The Cinematic Superhero Costume as Impossible by Dru H. Jeffries published in 2013 in „Cinephile: The Univesity of British Columbia’s Film Journal”. The author of the cited paper focuses on the topic of adapting male comic book characters’ costumes which is a starting point for the author of this article for in-depth analysis of this phenomenon including female superhero images.
Z genealogii nacjonalizmów w Hiszpanii, rec. książki: Magda Melnyk, Dlaczego Hiszpania trzeszczy?
Authors: Kubiaczyk Filip
Published: November 2021

Z genealogii nacjonalizmów w Hiszpanii, rec. książki: Magda Melnyk, Dlaczego Hiszpania trzeszczy?
Dziekanka/Tiegenhof – stan wiedzy o funkcjonowaniu zakładu podczas II wojny światowej
Authors: Tomczak Maria
Published: November 2021

The article presents the state of research on the history of the mental institution known as Dziekanka during World War II. New information discovered by German authors and increasing knowledge about the course of Aktion T4 makes it possible to verify erroneous findings and contributes new elements to the overall picture. For instance, it is demonstrated that not all of the murdered patients lost their lives as part of Aktion T4, or that – despite the claims of certain Polish authors – Tiegenhof was also a site where treatment and research did take place. The paper offers an overview of literature concerned with Dziekanka/Tiegenhof, discusses extermination of its patients, the individuals responsible and the connection with Aktion T4, as well as the significance of the institution in the Warthegau province; the question of the number of victims is also addressed.
Dielectric, ferroelectric and optical properties of Na and Nb co-doped (Bi0.5Na0.5)0.94Ba0.06TiO3
Authors: Ali Asif , Zahid Hina
Published: November 2021

[(Bi0.5Na0.5)0.94Ba0.06]1-xNaTi1-xNbO3 (x = 0.5 and 0.10) ceramics were prepared via conventional solid-state sintering route. X-ray diffraction analysis of the samples exhibited the formation of the cubic structure. Similar structure was observed from the Raman spectra of the samples. The optical band gap of the samples slightly decreased from 3.08 to 3.06 eV with increasing level of Na+ and Nb5+. The addition of Na+ and Nb5+ shifted Tm towards room temperature (RT). The sample x = 0.05 had a stable relative permittivity ɛr(mid) = 3914 across the temperature range 79-350 ℃ and tanδ < 0.025 (104-279 ℃). The energy density of sample with x = 0.05 was 0.4 J/cm3 which decreased to 0.32 J/cm3 at an applied electric field of 50 kV/cm with further substitution of Na+ and Nb5+ (i.e., x = 0.10).
Forming of CdZnTe thin films grown by hot wall epitaxy and their properties
Authors: Vuichyk M. , Rashkovets’kyi L. , Lavoryk S. , Lytvyn P. , Svezhentsova K.
Published: November 2021

In this work morphological, X-ray structural and optical studies of CdZnTe films grown by hot wall epitaxy method at relatively low substrate temperatures were performed. Possible mechanisms and processes of self-organization that occur during the growth of such structures are considered. It is shown that at thickness of film more than 130 nm on the surface, large (lateral size 150 - 200 nm, height - up to 10 nm) and small crystals are observed. The thicknesses and energy of the band gap width of the CdZnTe films grown at different growth times were determined. It is shown that the film absorption edge in the transmission spectra depends on the film thickness and the reasons for the shift of the film absorption edge are discussed.
El papel de la tecnología desde la perspectiva de Hanna Arendt
Authors: Díaz Sánchez Edisson
Published: November 2021

El presente artículo de reflexión busca realizar una delimitación del término tecnología, su demarcación conceptual y su relación con el mundo laboral y productivo, a partir de los planteamientos realizados por la teórica política alemana de origen judío Hanna Arendt (2009), en su libro La condición humana, en particular en el capítulo IV: “El trabajo”, donde plantea la supremacía del homo laborans sobre el homo faber, desde de una crítica al utilitarismo antropocéntrico de Kant y Protágoras que se refleja en las acciones y actuaciones del homo faber del mundo contemporáneo, para concluir en la importancia de la relación interdisciplinaria entre ciencia-técnica-tecnología dentro de los procesos de desarrollo de las sociedades actuales y la utilización de la tecnología como un medio, más no como un fin de poder, sobrevivencia y calidad de vida.
Analytic theory for current-voltage characteristic of a nanowire radial p-i-n diode
Authors:   . Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, 41, prospect Nauky, 03680 Kyiv, Ukraine, Borblik V.L.
Published: November 2021

In this article, process of current flow in a nanowire radial p-i-n diode has been considered in detail. It has been shown that cylindrical geometry of the structure gives rise to specific asymmetry of the concentration distribution for current carriers injected to the i-layer, which is opposite to asymmetry that is due to inequality of carriers’ mobilities. This specific asymmetry rises with bringing the i-layer nearer to the nanowire center. Together with that, decrease of the current density in a “long” p-i-n diode and its increase in a “short” p-i-n diode take place (at given forward voltage). And variation of radial thickness of the i-layer demonstrates maximums in the current density at the thickness close to the bipolar diffusion length.
The effect of surface plasmon-polaritons on the photostimulated diffusion in light-sensitive Ag–As4Ge30S66 structures
Authors:   V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 41, prospect Nauky, 03680 Kyiv, Ukraine, Indutnyi I.Z. , Mynko V.I. ,   V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 41, prospect Nauky, 03680 Kyiv, Ukraine, Sopinskyy M.V. ,   V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 41, prospect Nauky, 03680 Kyiv, Ukraine, Dan’ko V.A. ,   V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 41, prospect Nauky, 03680 Kyiv, Ukraine, Lytvyn P.M. ,   V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 41, prospect Nauky, 03680 Kyiv, Ukraine
Published: November 2021

The effect of surface plasmon-polaritons (SPPs) excited at the interface between the profiled surface of the silver layer (in the form of a diffraction grating) and the As4Ge30S66 layer on the photostimulated diffusion of silver into chalcogenide has been studied. The gratings with the period a = 519 nm and modulation depth h/a ≈ 0.037 (where h is the grating depth) were formed on chalcogenide photoresist films by using interferential lithography and covered with the 80-nm-thick aluminum layer, 85-nm-thick silver layer, and thin As4Ge30S66 layer. Photostimulated changes in this structure were studied measuring the angular dependences of specular reflection (Rp) of p-polarized light with the wavelength 632.8 nm. It was found that as a result of exposure, “degradation” (broadening, increase in reflection at the minimum) of the minimum in the angular dependence of Rp (which is associated with the SPP resonance) occurs faster, when the samples are irradiated at the angle corresponding to SPP excitation. This observation indicates acceleration of the photostimulated diffusion process in this structure under the plasmon field action.
Delta variant of SARS-CoV-2: characteristics and implications for public health in Colombia
Authors: Yomayusa Nacy , Vega Roman , Restrepo-Henao Alexandra , Morón Lina , Vaca Claudia , Oñate José
Published: November 2021

The SARS-CoV-2 Delta variant has become one of the greatest public health challenges worldwide since, after being first identified in India in December 2020, it has spread rapidly, affecting mainly countries with low vaccination rates and those that have relaxed the public health and social measures implemented to control the COVID-19 pandemic. The Delta variant has a higher replication capacity and is associated with viral loads up to 1 260 times higher than those of infections caused by the original strain, which may be associated with an increased likelihood of hospitalization, ICU admission, need for oxygen therapy, pneumonia, or even death. Fully vaccinated individuals have almost similar protection against both Delta and Alpha variants. Given the impact of Delta in countries where it is the dominant variant, it is necessary for all countries to develop systematic action plans focused on implementing strict public health and social measures in the context of the COVID-19 pandemic and on increasing vaccination coverage. Bearing this in mind, the objective of this reflection paper is to describe the main characteristics of the Delta variant, its impact on the dynamics of the pandemic in some of the countries where it has been detected, the effectiveness of vaccines against this variant, and its implications for public health in Colombia.