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Fabrication and Characterization of Bamboo—Epoxy Reinforced Composite for Thermal Insulation

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Open Journal of Composite Materials 2024年第1期14卷 15-32页

作者： Nandavardhan Reddy Kopparthi Jens schuster Yousuf Pasha Shaik Institute of Polymer Technology West Palatine University of Applied Sciences Kaiserslautern Pirmasens Germany

As global warming intensifies, researchers worldwide strive to develop effective ways to reduce heat transfer. Among the natural fiber composites studied extensively in recent decades, bamboo has emerged as a prime candidate for reinforcement. This woody plant offers inherent strengths, biodegradability, and abundant availability. due to its high cellulose content, its low thermal conductivity establishes bamboo as a thermally resistant material. Its low thermal conductivity, enhanced by a NaOH solution treatment, makes it an excellent thermally resistant material. Researchers incorporated Hollow Glass Microspheres (HGM) and Kaolin fillers into the epoxy matrix to improve the insulating properties of bamboo composites. These fillers substantially enhance thermal resistance, limiting heat transfer. Various compositions, like (30% HGM + 25% Bamboo + 65% Epoxy) and (30% Kaolin + 25% Bamboo + 45% Epoxy), were compared to identify the most efficient thermal insulator. Using Vacuum Assisted Resin Transfer Molding (VARTM) ensures uniform distribution of fillers and resin, creating a structurally sound thermal barrier. These reinforced composites, evaluated using the TOPSIS method, demonstrated their potential as high-performance materials combating heat transfer, offering a promising solution in the battle against climate change.

关键词： Thermal Insulator Rooftiles Hollow Glass Microspheres Bamboo Kaolin Epoxy VARTM Process Thermal Conductivity Mechanical Properties

Enhancing Stress Intensity Factor Reduction in Cracks Originating from a Circular Hole in a Rectangular Plate under Uniaxial Stress through Piezoelectric Actuation

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Materials Sciences and Applications 2024年第1期15卷 1-14页

作者： Gopi Krishna Konda Jens schuster Yousuf Pasha Shaik department of Applied Logistics and Polymer Sciences University of Applied Sciences Kaiserslautern Institute for Plastics Engineering West Pfalz (IKW) Pirmasens Germany

Circular holes are commonly employed in engineering designs;however, they often serve as locations where cracks initiate and propagate. This paper explores a novel approach to structural repair by utilizing piezoelectric actuators. The primary focus of this study is to investigate the influence of an adhesively bonded piezoelectric actuator patch placed above a circular hole on the stress intensity factor (SIF) in an aluminium plate. The plate is subjected to uniaxial tensile stress, while the piezoelectric actuator is excited with varying voltage levels. The analysis is conducted using the finite element method (FEM), a powerful numerical technique for simulating complex structures. The study assesses the stress distribution and employs the SIF as an adequate criterion for evaluating the impact of different patch configurations. The results indicate a strong correlation between the applied voltage and the SIF. Whether the SIF increases or decreases depends on the polarization of the piezoelectric actuator. Particularly noteworthy is the finding that rectangular patches in a horizontal orientation significantly reduce the SIF compared to other patch geometries. Moreover, double-sided patches exhibit a pronounced decrease in the SIF compared to single-sided patches. In summary, this research underscores the potential of piezoelectric actuators in mitigating stress intensity in structures with circular hole with crack initiation. It offers valuable insights into the influence of applied voltage, patch geometry, and patch placement on the SIF, thereby contributing to developing effective strategies for enhancing structural integrity.

关键词： Piezoelectric Actuators Stress Intensity Factor (SIF) Aluminium Plate Voltage Finite Element Method (FEM)

How aromatic dissolved organic matter differs in competitiveness against organic micropollutant adsorption

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Environmental Science and Ecotechnology 2024年第5期21卷 92-102页

作者： Qi Wang Oliver JLechtenfeld Luuk CRietveld Jonas schuster Mathias Ernst Roberta Hofman-Caris Jan Kaesler Chunmiao Wang Min Yang Jianwei Yu frederik Zietzschmann Key Laboratory of drinking Water Science and Technology Research Center for Eco-Environmental SciencesChinese Academy of Sciences100085BeijingChina delft University of Technology Department of Water ManagementPO Box 50482600GADelftthe Netherlands department of Analytical Chemistry Research Group BioGeoOmicsHelmholtz Centre for Environmental ResearchUFZPermoserstr.1504318LeipzigGermany Berliner Wasserbetriebe LaboratoryMotardstr.3513629BerlinGermany Institute for Water Resources and Water Supply Hamburg University of TechnologyAm Schwarzenberg-Campus 321073HamburgGermany KWR Watercycle Research Institute 3433PENieuwegeinthe Netherlands ProVISCentre for Chemical Microscopy Helmholtz Centre for Environmental ResearchUFZPermoserstr.1504318LeipzigGermany Wageningen University and Research Department of Environmental TechnologyBornse Weilanden 96708 WGWageningenthe Netherlands University of Chinese Academy of Sciences 100049BeijingChina

Activated carbon is employed for the adsorption of organic micropollutants(OMPs)from water,typically present in concentrations ranging from ng L1 to mg L***,the efficacy of OMP removal is considerably deteriorated due to competitive adsorption from background dissolved organic matter(dOM),present at substantially higher concentrations in mg L*** the characteristics of competitive dOM is crucial in predicting OMP adsorption efficiencies across diverse natural *** weight(MW),aromaticity,and polarity influence dOM *** the aromaticity-related metrics,such as UV254,of low MW dOM were proposed to correlate with dOM competitiveness,the method suffers from limitations in understanding the interplay of polarity and aromaticity in determining dOM ***,we elucidate the intricate influence of aromaticity and polarity in low MW dOM competition,spanning from a fraction level to a compound level,by employing direct sample injection liquid chromatography coupled with ultrahigh-resolution Fouriertransform ion cyclotron resonance mass *** exchange resin pre-treatment eliminated 93%of UV254-active dOM,predominantly aromatic and polar dOM,and only minimally alleviated dOM *** characterization revealed that nonpolar molecular formulas(constituting 26%PAC-adsorbable dOM)with medium aromaticity contributed more to the dOM *** analysis indicated that the competitiveness of highly aromatic LMW dOM compounds was strongly counterbalanced by increased *** aromaticity-derived p-p interaction cannot facilitate the competitive adsorption of hydrophilic dOM *** results underscore the constraints of depending solely on aromaticity-based approaches as the exclusive interpretive measure for dOM *** a broader context,this study demonstrates an effect-oriented dOM analysis,elucidating counterbalancing interactions of dOM molecular properties

关键词： Activated carbon Organic micropollutants dissolved organic matter(dOM) Multi-component adsorption Fourier-transform ion cyclotron resonance mass spectrometry(FT-ICR-MS)

development of Kaolin and Glass Fiber Reinforced Composites for Thermal Insulating Panels

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Open Journal of Composite Materials 2024年第1期14卷 44-59页

作者： Jagadiswar Reddy Tippi Reddy Jens schuster Yousuf Pasha Shaik department of Applied Logistics and Polymer Sciences University of Applied Sciences Kaiserslautern Institute for Plastics Engineering West Pfalz (IKW) Pirmasens Germany

In our modern world, where conserving energy is highly valued, thermal insulation panels play a crucial role in reducing heat transfer between two spaces, surfaces, or materials. They are used to enhance the energy efficiency of various industrial applications by minimizing heat loss and temperature control. These panels function as silent protectors, aiding in reducing energy consumption and making things more sustainable and better for the environment. This is where composite materials come in;they are known for their lightweight nature, high strength-to-weight ratio, and excellent thermal insulation properties and have gained significant attention. Researchers are actively engaged in various studies aimed at enhancing these materials further. This research project focuses on the development of kaolin and glass fiber-reinforced composites for thermally insulating panels, to which natural strengthening materials like corn husk and bamboo fibers are added. The aim is to create cost-effective and efficient composite materials for thermal insulation applications by incorporating these components with a binder consisting of potassium silicate, hydroxide, and distilled water. This project involves conducting compression tests, bending tests, impact tests, thermal conductivity measurements, and microscopic analysis to evaluate the mechanical and thermal properties of the developed composites. The profound impact of these engineered composites on thermal insulation panels stands to revolutionize energy conservation efforts, offering a potent avenue to minimize heat loss and enhance overall energy efficiency across an array of industrial sectors.

关键词： Kaolin Glass Fiber Corn Husk Bamboo Potassium Silicate Potassium Hydroxide

On the origin of the high tensile strength and ductility of additively manufactured 316L stainless steel: Multiscale investigation

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Journal of Materials Science & Technology 2020年第6期41卷 209-218页

作者： Bassem Barkia Pascal Aubry Paul Haghi-Ashtiani Thierry Auger Lionel Gosmain fréd.ric schuster Hicham Maskrot dEN-Service d’Etudes Analytiques et de Réactivitédes Surfaces CEAUniversitéParis-Saclay91191France Laboratoire de Mécanique des Sols Structures et MatériauxCentralesupélecUMR CNRS 8579UniversitéParis-Saclay92295France Arts et Métiers ParisTech PIMMUMR CNRS 800675013 ParisFrance CEA Cross-Cutting Program on Materials and Processes Skills 91191Gif-sur-YvetteFrance

We report that 316L austenitic stainless steel fabricated by direct laser deposition(dLd),an additive manufacturing(AM)process,have a higher yield strength than that of conventional 316L while keeping high *** interestingly,no clear anisotropy in tensile properties was observed between the building and the scanning direction of the 3d printed *** examination of the as-built parts shows a heterogeneous solidification cellular *** electron microscopy observations coupled with Energy dispersive X-ray Spectrometry(EdS)reveal the presence of chemical micro-segregation correlated with high dislocation density at cell boundaries as well as the in-situ formation of well-dispersed oxides and transition-metal-rich *** hierarchical heterogeneous microstructure in the AM parts induces excellent strength of the 316L stainless steel while the low staking fault energy of the as-built 316L promotes the occurrence of abundant deformation twinning,in the origin of the high ductility of the AM *** additional post-process treatments,the AM 316L proves that it can be used as a structural material or component for repair in mechanical construction.

关键词： Additive manufacturing Austenitic stainless steel dislocation structure Twinning Mechanical behavior Anisotropy

Littoral landforms of Lake Hulun and Lake Buir(China and Mongolia):Wind-driven hydro-sedimentary dynamics and resulting clastics distribution

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Journal of Palaeogeography 2024年第2期13卷 309-326页

作者： Li Wang Mathieu schuster Shi-Wei Xin Florin Zainescu Xin-Yu Xue Joep Storms Jan-Hendrik May Alexis Nutz Helena van der Vegt Guilherme Bozetti Zai-Xing Jiang School of Energy Resources China University of Geosciences(Beijing)Beijing100083China Universite de Strasbourg CNRSENGEESInstitut Terre et Environnement de StrasbourgUMR 70635 Rue DescartesStrasbourgFrance Tamsag Mongolia(XIX)Ltd. PetroChinaDaqing 163000China CEREGE Aix-Marseille UniversitéCNESIRDCollege de FranceINRAAix en ProvenceFrance School of Marine Science Sun Yat-sen UniversityZhuhai 519083China delft University of Technology Department of Geoscience and EngineeringDelfthe Netherlands School of Geography Earth and Atmospheric SciencesUniversity of Melbourne253 Elgin St.CarltonVIC 3053Australia deltares Delfthe Netherlands SCMF Faculty of GeographyUniversity of Bucharest1 N.Balcescu Blv.BucharestRomania

Two rectangular-shaped lakes,Lake Hulun and Lake Buir,located at the boundary between China and Mongolia,only c.75 km apart and therefore experiencing similar wind fields,have been studied based on satellite images and field surveys in order to compare their geomorphological and sedimentological *** wind-driven hydrodynamics,which have a significant effect on the development of littoral landforms and on sediment distribution,have been discussed for the two similar lakes that experienced a prevailing wind perpendicular to their long axis.A conceptual model related to wind-driven water bodies and sediment distribution is ***-influenced to wave-dominated deltas,beaches,spits,and eolian dune deposits develop around these two lakes,with a strikingly similar distribution *** features locally inform the longshore drift and help reconstruct the water circulation induced by wind *** the NW prevailing wind regime,the spits developed on the SW coast with a NW—SE extension,which was influenced by the NW—SE longshore *** same influence was observed in the delta extension in the NE *** differences lie in the presence of fan deltas in the NW region of Lake Hulun,but not in Lake ***,the width of the beach and eolian deposits on the downwind coast of Lake Hulun is three times greater than that of Lake Buir which were caused by the differences in sediment supply and wind fetch between the two *** Hulun and Lake Buir provide two reliable examples to understand the relationship among the wind field,provenance,hydrodynamics,landforms,and asymmetrical distribution of clastics in elongated *** also represent relevant modern analogs,which may also be of guiding significance to wind-driven sand body prediction in lacustrine basins.

关键词： Wind-driven lakes Fetch Sedimentary facies Hydrodynamics Geomorphology Spits Shoreline Lake Hulun Lake Buir

development of Morus alba Reinforced Poly-Lactic Acid with Elevated Mechanical and Thermal Properties

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Materials Sciences and Applications 2024年第7期15卷 186-200页

作者： Girish Kumar Reddy Madda Jens schuster Yousuf Pasha Shaik department of Applied Logistics and Polymer Sciences University of Applied Sciences Kaiserslautern Institute for Plastics Engineering West Pfalz (IKW) Pirmasens Germany

This research investigates the mechanical and thermal properties of Morus alba combined with polylactic acid in comparison with other natural fibers. The study uses three different fiber and PLA compositions - 20%, 30%, and 40% respectively - to produce composite materials. In addition, another composite with the same fiber volume is treated with a 4% NaOH solution to improve mechanical properties. The composites are processed by twin-screw extrusion, granulation, and injection molding. Tensile strength measurements of raw fibers and NaOH-treated fibers were carried out using a single-fiber tensile test with a gauge length of 40 mm. It was observed that the NaOH surface treatment increases the resistance against tensile loading and exhibited improved properties for raw fiber strands. The diameter of the fibers was measured using optical microscopy. during this research, flexural tests, impact tests, differential scanning calorimetry (dSC), and heat deflection temperature measurements (HdT) were conducted to evaluate the mechanical and thermal properties of the developed composite samples. The results indicate that the mechanical properties of NaOH-treated Morus alba-reinforced polylactic acid outperform both virgin PLA samples and untreated Morus alba samples.

关键词： Morus Alba Fiber (MAF) White Mulberry Polylactic Acid (PLA) Sodium Hydroxide (NaOH) Solution Single Fiber Tensile Test Thermal Stability Optical Microscopy

Computing Open-Loop Optimal Control of the q-Profile in Ramp-Up Tokamak Plasmas Using the Minimal-Surface Theory

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Plasma Science and Technology 2013年第5期15卷 403-410页

作者：许超欧勇盛 Eugenio schuster 于欣 The State Key Laboratory of Industrial Control Technology Zhejiang University Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences department of Mechanical Engineering & Mechanics Lehigh University Ningbo Institute of Technology Zhejiang University

The q-profile control problem in the ramp-up phase of plasma discharges is consid- ered in this work. The magnetic diffusion partial differential equation （PdE） models the dynamics of the poloidal magnetic flux profile, which is used in this work to formulate a PdE-constrained op-timization problem under a quasi-static assumption. The minimum surface theory and constrained numeric optimization are then applied to achieve suboptimal solutions. Since the transient dy- namics is pre-given by the minimum surface theory, then this method can dramatically accelerate the solution process. In order to be robust under external uncertainties in real implementations, PId （proportional-integral-derivative） controllers are used to force the actuators to follow the computational input trajectories. It has the potential to implement in real-time for long time discharges by combining this method with the magnetic equilibrium update.

关键词： advanced plasma operations current profile dynamics optimal control theory,minimal surface equation differential geometry

GPS tracking of non-breeding ravens reveals the importance of anthropogenic food sources during their dispersal in the Eastern Alps

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Current Zoology 2016年第4期62卷 337-344页

作者： Matthias-Claudio LORETTO richard schuster Thomas BUGNYAR department of Cognitive Biology University of Vienna Althanstrasse 14 A-1090 vienna Konrad Lorenz Forschungsstelle Core Facility for Behaviour and Cognition University of Vienna Fischerau 11 A-4645 GrLinau im Almtal Austria Cdepartment of Forest and Conservation Sciences University of British Columbia Vancouver B.C. Canada V6T1Z4

In many songbirds, the space use of breeders is well studied but poorly understood for non-breeders. In common ravens, some studies of non-breeders indicate high vagrancy with large individual differences in home range size, whereas others show that up to 40% of marked non-breeders can be regularly observed at the same anthropogenic food source over months to years. The aim of this study was to provide new insights on ravens＇ behavior during dispersal in the Eastern Alps. We deployed Global Positioning System （GPS） loggers on 10 individuals to gather accurate spatial and temporal information on their movements to quantify： 1） the dimension of the birds＇ space use （home range size with seasonal effects and daily/long-term travel distances）, 2） how long they stayed in a dispersal stage of wandering as opposed to settling temporarily, and 3） their destination of movements. We recorded movements of up to 40km per hour, more than 160km within 1 day and more than 11,000 km within 20 months, indicating high vagrancy. Switching frequently between temporarily settling and travelling large distances in short time intervals leads to extensive home ranges, which also explains and com- bines the different findings in the literature. The destinations are rich anthropogenic food sources, where the birds spent on average 75% of their time. We discuss how ravens may find these ＂feeding hot spots＂ and which factors may influence their decision to stay/leave a site. The strong dependence on anthropogenic resources found in this population may have implications for site management and conservation issues.

关键词： common raven Corvus corax non-breeder space use dispersal kernel density.