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TIME AND POLING HISTORY DEPENDENT ENERGY STORAGE AND DISCHARGE bEHAVIORS IN POLY(VINYLIDENE FLUORIDE-CO-HEXAFLUOROPROPYLENE) RANDOM COPOLYMERS

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Chinese Journal of Polymer science 2011年第1期29卷 65-80页

作者： Fang-xiao Guan Jing Wang Ji-lin Pan Qing Wang Lei Zhu Polymer Program Institute of Materials Science and Department of Chemical Materials and Biomolecular Engineering University of Connecticut Storrs Connecticut 06269-3136 USA b Department of Materials Science and Engineering Pennsylvania State University University Park Pennsylvania 16802 USA Department of Maeromolecular Science and Engineering Case Western Reserve University Cleveland Ohio 44106-7202 USA

We studied cycle time （0.01-10 s with triangular input waves） and poling history （continuous versus fresh poling） dependent electric energy storage and discharge behaviors in poly（vinylidene fluoride-co-hexafluoropropylene） [P（VDF- HFP）] films using the electric displacement -- the electric field （D-E） hysteresis loop measurements. Since the permanent dipoles in PVDF are orientational in nature, it is generally considered that both charging and discharging processes should be time and poling history dependent. Intriguingly, our experimental results showed that the charging process depended heavily on the cycle time and the prior poling history, and thus the D-E hysteresis loops had different shapes accordingly. However, the discharged energy density did not change no matter how the D-E loop shape varied due to different measurements. This experimental result could be explained in terms of reversible and irreversible polarizations. The reversible polarization could be charged and discharged fairly quickly （〈 5 ms for each process）, while the irreversible polarization depended heavily on the poling time and the prior poling history. This study suggests that it is only meaningful to compare the discharged energy density for PVDF and its copolymer films when different cycle times and poling histories are used.

关键词： P（VDF-HFP） random copolymer Charging and discharging behaviors Time and poling history dependence Dipole switching Compensation polarization.

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Utilization of Pineapple Crown Fiber and Recycled Polypropylene for Production of Sustainable Composites

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Journal of Renewable materials 2020年第10期8卷 1327-1341页

作者： Alexandra Augusta Reichert Mariana Ribas de Sá Gabriela Escobar Hochmuller da Silva Cesar Augusto Gonçalves beatrice AndréRicardo Fajardo Amanda Dantas de Oliveira Postgraduate Program in Materials Science and Engineering(PPGCEM) Federal University of Pelotas(UFPel)Pelotas96075-630Brazil Technology Development Center(CDTec) Materials EngineeringFederal University of Pelotas(UFPel)Pelotas96075-630Brazil Postgraduate Program in Materials Science and Engineering(PPGCEM) Federal University of São Carlos(UFSCar)São Carlos13565-905Brazil Laboratory of Technology and Development of Composites and Polymeric Materials Federal University of Pelotas(UFPel)Pelotas96010-900Brazil

Nowadays,the production of consumer goods is based on the use of non-renewable raw materials,which in recent years has been performing as a problem for the *** the large number of available biofibers in nature,their use in the development of polymeric composites has inevitably emerged,it is also necessary to take into account the countless discarded plastics that still have the potential to be *** this work,fibers were extracted from pineapple crown residues and utilized to compose sustainable composites using recycled polypropylene from cups discarded in the trash as a ***,it is known that for good performance,it is necessary to achieve a good chemical interaction between the fiber and the *** order to improve this interaction,alkaline mercerization treatment was carried out on the surface of the fibers removing some components incompatible with the *** this work,the effect of the mercerization treatment on the properties of the fibers was studied,as well as their interaction with the *** effect of fiber concentration on the mechanical and thermal properties of composites was also *** of 5 and 7 wt%were used for both natural and mercerized fibers.A decrease in the number of degradation stages was observed through thermogravimetry analyses(from four in natural fiber to two in mercerized fibers),showing that the mercerization performed on the fibers was *** increase in the degree of crystallinity of mercerized fibers was also observed through the results of X-ray *** techniques indicate that amorphous compounds,such as hemicellulose and lignin,were partially *** the tensile test,it could be noted that all composites presented higher values of de elastic modulus than recycled polypropylene without added load;however,there were no differences in the elastic modulus between the different types of fibers and load ***,it is interesting to use fibers as r

关键词： Recycling composites polypropylene biofibers pineapple crown

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Effect of dual modification on structural, functional and dielectric properties of cassava starch

Food Physics

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Food Physics 2025年 2卷

作者： Cremasco, Paula Figueiredo M. Siqueira, Karine Mayuri Pistoni Sobral, Paulo José do Amaral Velloso, Walter Ferreira de Lima, César Gonçalves Gut, Jorge Andrey Wilhelms Moraes, Izabel Cristina Freitas Postgraduate Program in Materials Science and Engineering Faculty of Animal Science and Food Engineering University of São Paulo Avenue Duque de Caxias Norte São Paulo Pirassununga 13635900 Brazil Department of Biossistems Engineering Faculty of Animal Science and Food Engineering University of São Paulo Avenue Duque de Caxias Norte São Paulo Pirassununga 13635900 Brazil Department of Food Engineering Faculty of Animal Science and Food Engineering University of São Paulo Avenue Duque de Caxias Norte São Paulo Pirassununga 13635900 Brazil Food Research Center (FoRC) University of São Paulo Lake Street São Paulo São Paulo 05508-080 Brazil Departament of Basic Sciences Faculty of Animal Science and Food Engineering University of São Paulo Avenue Duque de Caxias Norte São Paulo Pirassununga 13635900 Brazil Department of Chemical Engineering Polytechnic School University of São Paulo Lake Street São Paulo São Paulo 05508-080 Brazil

The combined effect of hydrocolloid addition and microwave heating on the structural, physical and functional properties of cassava starch remains underexplored, despite individual studies on these modification methods. The dielectric properties, important for the microwave treatment of starch, have received little attention in recent studies. Cassava starch with and without addition of hydrocolloids (guar and xanthan gums) was modified by microwave heating for two different exposure times, and its structural, functional, and dielectric properties were studied. The dual modification enhanced the swelling power and oil holding capacity of the starch, reduced its gelatinization temperature, and did not alter its crystallinity. Notably, xanthan-modified starch microwaved for 6 min exhibited higher color variation (ΔE*) and increased granules agglomeration, while the microwave treatment alone roughened the surface of the starch granules. The mean diameters D[4,3] of starch increased with xanthan gum addition, microwave treatment (6 min), and their combination. The relative permittivity (ε’), loss factor (ε”) and penetration depth (Db>p)b> were lower for samples modified by the combined method. Considering the type of hydrocolloid and the microwave exposure time, the combined modification significantly influenced the properties of starch, offering a promising approach to producing starch with enhanced functional properties. © 2024 KeAi Communications Co., Ltd

关键词： biopolymers Cassava starch Guar Microwave Xanthan

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Methane reforming reactions for hydrogen production using hydrotalcite precursors and nanofibers based catalysts 12

Methane reforming reactions for hydrogen production using hy...

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12th International Renewable Energy Congress, IREC 2021

作者： Silva, Thamyscira Chaghouri, Muriel Tidahy, Lucette Haingomalala Gennequin, Cedric Abi-Aad, Edmond Cesario, Moises MacEdo, Daniel Dunkerque France Federal University Of Paraiba Materials Science And Engineering Postgraduate Program Joao Pessoa Brazil

ISBN: (纸本)9781665432900

CoNiMg4Al2 catalysts were synthesized using two different methods: solution blow spinning to produce nanofibers (NF), and co-precipitation to produce hydrotalcite precursors (HT). Part of the hydrotalcite sample was ground (GR) using mechanical milling to determine the effect of grinding on the catalytic performance. The three materials (NF, HT and GR) were tested in the dry and steam reforming of methane (DRM, SRM respectively) reactions during 12h stability tests at 700°C. The calcined and the used catalysts were characterized using XRD and DTA/TG analysis. All catalysts were active during the SRM and DRM tests;however, nanofibers showed a slightly higher activity in both reactions. The dry reforming of methane reaction was more susceptible to the formation of carbon deposition leading to the deactivation of the ground catalyst. © 2021 IEEE.

关键词： Methane

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Polymer blends of poly(lactic acid) and starch for the production of films applied in food packaging: A brief review

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Polymers from Renewable Resources 2023年第2期14卷 108-153页

作者： Carneiro da Silva, Lucas Rafael Rios, Alessandro de Oliveira Campomanes Santana, Ruth Marlene Postgraduate Program in Mining Metallurgical and Materials Engineering Laboratory of Polymeric Materials Federal University of Rio Grande do Sul Rio Grande do Sul Brazil Postgraduate Program in Food Science and Technology Laboratory of Bioactive Compounds Federal University of Rio Grande do Sul Rio Grande do Sul Brazil

The limited degradation of synthetic polymers used in food packaging when discarded in the environment is a major concern for society. Therefore, industry and academia have sought to develop biodegradable and eco-friendly materials for single-use in packaging. An interesting alternative for the food industry is biodegradable polymeric films, which is why different biopolymers have been used in the production of sustainable packaging. It is worth mentioning that the use of biodegradable polymers is one of the most successful innovations in the industry to address issues related to the environment. Among the available raw materials, starch extracted from different renewable sources is very promising for this purpose, due to its abundance, low-cost compared to other polymers and ability to produce non-toxic films. However, when used alone, pure starch has many limitations, which can be overcome by developing a mixture with other polymers (polymer blends), preferably from renewable and biodegradable sources, such as poly(lactic acid) (PLA). In this context, the absence of literature reviews evidencing the results of the application of films in foods led us to write this article, given the importance of polymer blends produced with different types of starch (cassava, corn, pea, potato, rice and wheat) and the PLA matrix. According to the results, it is clear that polymer blends based on PLA/Starch for food packaging are very promising, already being part of the industries solutions, aiming to minimize the large volume of plastic waste of petrochemical origin discarded in nature. Obviously, as with any technology, more research is needed to further improve the performance of the films, and while much research has made great strides, there are still limitations that prevent the commercialization of these materials. © The Author(s) 2023.

关键词： Starch

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Mechanical and Electrochemical Synergism of API X42 Pipeline Steel During Erosion–Corrosion

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Journal of bio- and Tribo-Corrosion 2015年第4期1卷 1-18页

作者： Aminul Islam, Md. Farhat, Zoheir N. Department of Process Engineering and Applied Science Materials Engineering Program Dalhousie University HalifaxNSB3J 2X4 Canada

Hydro-transportation is an economic and flexible way to transport natural resources such as oil and gas from excavation to the extraction plants, refineries, and consumer-ready products to markets. However, interaction between solid particles, corrosive fluid, and target material often results in significant mutual reinforcement due to the combined action of erosion and corrosion. In this study, erosion–corrosion behavior of API pipeline steel has been assessed in 2 g l−1 NaCl solution purged with CO2 as the corrosive media and aluminum oxide as the erodent. Four different particle velocities (36, 47, 63, and 81 m s−1) were employed, while the angle of incidence was kept constant at 90°. The synergism between erosion and corrosion has been studied by means of a newly designed test approach to mitigate the limitations of the in situ method and to identify the effect of erosion on corrosion and vice versa. The corrosion process was monitored using potentiodynamic polarization and weight loss measurements. Total material loss rate and the components of erosion, corrosion, and their synergistic interactions have been determined. Scanning electron microscopy examination and experimental results show that there is an immense correlation between erosion and corrosion. Significant synergism was observed due to the interaction of different erosion and corrosion mechanisms. © 2015, Springer International Publishing AG.

关键词： Aluminum oxide

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Effect of exposure to a light-emitting diode (LED) on the physicochemical characteristics of natural latex biomembranes used to treat diabetic ulcers

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Research on biomedical engineering 2022年第3期38卷 901-911页

作者： Santana, Thamis Fernandes Oliveira, Rebeca Hannah de Melo dos Santos, Ludmila Evangelista Lima, Eunice Paloma Nascimento Faria, Sylvia de Sousa Fonseca, Marcos Augusto Moutinho da Silva, Jaqueline Rodrigues Tatmatsu-Rocha, José Carlos Gomes, Marília Miranda Forte Fleury Rosa, Mário Fabrício Fleury Rosa, Suélia de Siqueira Rodrigues Carneiro, Marcella Lemos brettas Postgraduate Program in Biomedical Engineering University of Brasilia Federal District Brasilia Brazil Postgraduate Program in Materials Science and Engineering Federal University of Campina Grande Paraiba Campina Grande Brazil Department of Electrical Engineering University of Brasilia Federal District Brasilia Brazil Postgraduate Program in Biology Animal University of Brasilia Federal District Brasilia Brazil Medicine Faculty Physical Therapy Department Federal University of Ceara Ceara Fortaleza Brazil Postgraduate Technology and Health Program University of Brasília Federal District Brasília Brazil

Purpose: Natural latex biomembrane has shown high therapeutic potential for the treatment of diabetic ulcers when associated with phototherapy. In this study, physical and chemical alterations in the latex biomembranes were evaluated after exposure to light-emitting diode (LED) irradiation and after contact with NaCl solution. Methods: There were three experimental groups: natural latex biomembranes (1) in natura;(2) after 35 min of LED light irradiation;and (3) after immersion in NaCl 0.9 g% solution. The samples were analyzed by tensile strength test, thermogravimetry, contact angle wettability, and Fourier-transform infrared spectroscopy. Results: The biomembranes that were submitted to contact with NaCl aqueous solution or exposure to LED did not undergo impairment of mechanical resistance. The thermogravimetry analysis indicated that increasing temperature led to mass loss in all samples, referring to their decomposition temperatures. In the wettability test, biomembranes exposed to LED showed a significant reduction in the contact angle between 0 and 10 min, indicating an increase in hydrophilicity, suggesting water storage capacity. The Fourier-transform infrared spectrometry assay showed that there was a more significant reduction in vibration intensity after immersion in NaCl solution compared to untreated biomembranes. An increase in the intensity of the entire spectrum of biomembranes exposed to LED was observed in comparison with the other samples, which may be related to photodegradation caused by LED light irradiation. Conclusion: The biomembranes underwent significant changes in its chemical structure after being subjected to different types of exposure and maintained its elasticity and tensile strength properties, in addition to showing good water retention capacity after exposure to LED. Thus, it maintains many of its properties for application as a tissue-regenerating biomaterial, even when subjected to LED irradiation and a humid environment. © 20

关键词： Tissue regeneration

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Phase formation, microstructural and superconducting properties of YbCO added Ca-compounds extraction eggshells

Results in Materials

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Results in materials 2025年 26卷

作者： Yap, Siew Hong Awang Kechik, Mohd Mustafa Humaidi, Syahrul Mohd Shariff, Khairul Khaizi baqiah, Hussien Chen, Soo Kien Lim, Kean Pah Mohd Zaid, Mohd Hafiz Yaakob, Yazid Abdul Karim, Mohd Khalis Talib, Zainal Abidin Loh, Zhi Wei Kamarudin, Aliah Nursyahirah Shaari, Abdul Halim Miryala, Muralidhar Superconductor & Thin Films Laboratory Department of Physics Faculty of Science Universiti Putra Malaysia UPM Serdang Selangor Darul Ehsan 43400 Malaysia Postgraduate Program (Physics) FMIPA Universitas Sumatera Utara Medan 20222 Indonesia Microwave Research Institute Universiti Teknologi MARA Selangor Shah Alam 40450 Malaysia Shandong Key Laboratory of Biophysics Institute of Biophysics Dezhou University No. 566 University Rd. West Shandong Dezhou China Department of Physics College of Natural Sciences Jeonbuk National University 567 Baekjedaero Deokjingu Jeollabukdo Jeonjusi 54896 South Korea Materials for Energy and Environmental Laboratory Superconducting Materials Group of Science & Engineering Shibaura Institute of Technology 3-7-5 Foxesu Koto-ku Tokyo 135-8548 Japan

For several decades now, the emergence and production of high-quality bulk rare-earth-based superconductors, particularly Yba2Cu3O7-δ (YbCO/Y-123), have been noteworthy advancements with potential implications in var... 详细信息

For several decades now, the emergence and production of high-quality bulk rare-earth-based superconductors, particularly Ybab>2b>Cub>3b>Ob>7-δb> (YbCO/Y-123), have been noteworthy advancements with potential implications in various fields. This unique research investigated the potential of using chicken eggshells as a source of calcium compounds (CaO, CaCOb>3b> and Ca(OH)b>2b>) for the synthesis of YbCO. The green approach synthesis of YbCO added with Ca-compounds (0.0100 wt% ≤ x ≤ 0.6000 wt%) was conducted in a systematic manner via thermal treatment method. The crystal structure, surface morphology, and chemical composition of the specimens were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), and Energy Dispersive X-Ray Spectroscopy (EDX). The results showed the formation of orthorhombic Y-123 phase, Pmmm space group with the high-intensity peaks of Y-123. The addition of Ca-compounds proposed a different trend of grain degradations in the YbCO matrix system with the appearance of Ca-compounds' impurity phases. The superconducting properties such as electrical resistivity analyzed using electrical resistance measurement. Surprisingly, the superconducting parameters improved after Ca-compounds were added into the YbCO system. The hole concentration, p reached the highest value among all the specimens with the lowest superconducting transition width, ∼ΔTb>cb> = 3.805 K (Tb>c-onsetb> = 93.223 K and Tb>c(R = 0)b> = 89.418 K) for the lowest concentration of Ca-compounds i.e., 0.0375 wt%. This great finding targeted the green approach impurity materials into YbCO system that can usefully enhance the superconducting properties at high temperature which covers the idea of addition with deficient concentration Ca-compounds. © 2025

关键词： Ca-compounds Critical temperature Grains degradations Hole concentration Superconducting transition width

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Meteorological data implications modeling on evapotranspiration variability in arid and semi-arid zones in Saudi Arabia using hybrid metaheuristic

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Scientific Reports 2025年第1期15卷 1-22页

作者： Noureddine, Oulad Naoui Mohamed, Sekkoum El Amine, Cherif Alzaed, Ali Gedfew, Meseret Abeje Ghoneim, Sherif S. M. Hussein, Enas E. Materials Energy Systems Technology and Environment Laboratory Department of Hydraulic and Civil Engineering University Ghardaia Bounoura Algeria Department of Civil Engineering Faculty of Civil Engineering and Architecture Amar Telidji University P. O. Box 37.G Laghouat 03000 Algeria Water Management and Treatment Laboratory University of Science and Technology of Oran Mohamed Boudiaf B.P. 1505 El M’Naouer Oran Algeria Architectural Engineering Program - Civil Engineering Department Faculty of Engineering Taif University Taif 21944 Saudi Arabia Department of Civil Engineering Faculty of Technology Debre Markos University P. O. Box 269 Debre Markos Ethiopia Department of Electrical Engineering College of Engineering Taif University Taif 21944 Saudi Arabia Water Management Research Institute National Water Research Center Shubra El-Kheima 13411 Egypt

This work is unique and contributes new knowledge to the field whereas it involves introducing a new method based on coupling two or three stochastic models, analyzing new data represented by drought and flooding risk relationship, and addressing a previously unexplored research question: Can we make a decision regarding future evapotranspiration-flooding risk relationship? In this paper, the bat algorithm (bAT) with the Newton Method (NM), bird Swarm Algorithm (bSA), Genetic Algorithm (GA), and Chicken Swarm Optimization Algorithm (CSO) are used as a hybrid model in arid and semi-arid zones in Saudi Arabia as well as for modeling rainfall, temperature, and solar radiation implications on evapotranspiration variability. Coupling between aridity and evapotranspiration over a long time can create flooding risks. This holistic modeling aims to reduce flooding risks and ensure the desired decision. Several models were employed to simulate some basins’ Potential and Actual evapotranspiration as case studies. The meteorological inputs of the hybrid models were calibrated and validated with metric evaluation for input and output of evapotranspiration, respectively. The results suggest that the application of a hybrid model can improve the accuracy of evapotranspiration simulations in terms of statistical parameters, whereas bAT–GA–NM reduced MAPE from 38.88 to 4.16% for Mekkah and from 14.94 to 2.04% for Medina and NSCE from − 0.17 to 0.97 for Mekkah and from 0.82 to 0.99%. Those parameters will provide a better understanding of evapotranspiration processes in watersheds and valuable information for early warnings of flooding risks. © The Author(s) 2025.

关键词： Evapotranspiration Hybrid metaheuristic Modeling Rainfall Solar radiation data Temperature

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Substitution effect of (Mn, Ti) to the dielectric properties of barium-strontium hexaferrite for absorbing electromagnetic waves

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AIP Conference Proceedings 2011年第1期1454卷 282-285页

作者： Repi, V. Vekky R. Manaf, Azwar Postgraduate Program of Materials Science Faculty of Mathematics and Natural Science Universitas Indonesia Jakarta 10430 Jalan Salemba Raya 4 Indonesia Faculty of Engineering and Science Department of Engineering Physics Universitas Nasional Jakarta 12520 Indonesia

The objective of this work is to evaluate the ability of Mn-Ti substituted barium-strontium hexaferrite to absorb high frequency electromagnetic wave. To accomplish this objective, Mn-Ti substituted barium strontium hexaferrite of ba0.5Sr0.5Fe12-x(Mn0.5Ti0.5)x with x = 0.1, x=0.3, x=0.5 were prepared through mechanical alloying route. Phase identification of the material obtained from XRD pattern indicating that the material is single phase for all variations of x. Coercivity and the remanent obtained by analyzing the hysteresis curve. The lowest coercivity at x = 0.5 for 77.86 kA/m but also lower the remanent of 0.088 kA/m. Dielectric properties of the material traced by calculating the value of permittivity and permeability of the material that was obtained with the parameters of the scattering vector network analyzer (VNA) in the 8GHz to 12GHz range. © 2012 American Institute of Physics.

关键词： barium-strontium hexaferrite Electromagnetic wave absorber Mechanical alloying Permittivity and permeability

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