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Effect of Concentration and Residence Time of Joncryl■ADR4368 on Melt Processability of Poly(3-hydroxybutyrate)

Journal of Renewable materials 2024年第12期12卷 2079-2094页

作者： Jéssica da Silva Chagas JoséElson Soares Filho Natália Fernanda Inocêncio Silva Marcelo Massayoshi Ueki Eliton Souto de Medeiros Renate Maria Ramos Wellen Mauricio Pinheiro de Oliveira Gelsoneide da Silva Gois Yêda Medeiros Bastos de Almeida Amélia S.F.Santos Post-Graduation Program in Materials Engineering(PPCEM) Federal University of Paraíba(UFPB)João PessoaPB 58051-900Brazil Laboratory of Materials and Biosystems(LAMAB) Federal University of Paraíba(UFPB)João PessoaPB 58051-900Brazil Department of Materials Engineering Federal University of Sergipe(UFS)Jardim Rosa ElzeSão CristóvãoSE 49100-000Brazil Institute of Science and Technology Federal University of São Paulo(UNIFESP)São Josédos CamposSP 12231-280Brazil Department of Chemical Engineering Federal University of Pernambuco(UFPE)Cidade UniversitáriaRecifePE 50670-901Brazil

Poly(3-hydroxybutyrate)(PHB)is a biothechnological and biodegradable thermoplastic polymer from the polyhydroxyalkanoates(PHAs)family,whose chain regularity,high molecular weight,and physical and mechanical properties comparable to polypropylene(PP)are characteristics that have made PHB a prominent commercial ***,its susceptibility to thermal degradation and hydrolysis has limited many *** address the challenges associated with processing,a random copolymer of 95.86 mol%3-hydroxybutyrate and 4.14 mol%3-hydroxyvalerate(referred as PHB)was compounded without(neat PHB)and with 0.25,0.5,1,and 1.5 wt%of chain extender(Joncryl■ADR 4368),consisting of multifunctional epoxy groups,and melt mixed in an internal mixer at 170℃,50 rpm,and residence times of 5,10,and 15 *** effect of chain extender concentration and residence time on the effectiveness of Joncryl■ADR 4368 to recover the pristine PHB properties were investigated through torque rheometry,melt flow index(MFI),differential scanning calorimetry(DSC),tensile testing,and thermogravimetric *** results indicated that an increase in residence time strongly influenced the prevalence of thermomechanical degradation reactions over chain extension reactions of PHB during processing in the molten *** residence times favored chain extension,while longer times favored chain *** trend led to no enhancement of PHB mechanical properties processed for 10 and 15 min,regardless of additive content *** flow index,thermogravimetric analysis and tensile strength exhibited an asymptotic behavior with the increase in additive concentration,exhibiting a noteworthy improvement in tensile strength and temperature at the highest rate of thermal degradation(TMAX),and a decrease in melt flow index of neat PHB with only 0.25 wt%of additive mixed for 5 *** results found in this work allow additional data for processing PHB by manipulating the ratios of multifunctional chain

关键词： PHB chain extender degradation epoxy groups viscosity

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Deformation of porous, nanostructured silver at room temperature and 150C°

Deformation of porous, nanostructured silver at room tempera...

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2012 MRS Fall Meeting

作者： Noiseau, Guillaume Becker, Michael F. Keto, John W. Kovar, Desiderio Materials Science and Engineering Graduate Program University of Texas at Austin Austin TX 78712-1591 United States Department of Electrical and Computer Engineering University of Texas Austin TX United States Department of Physics University of Texas Austin TX United States Department of Mechanical Engineering University of Texas Austin TX United States

ISBN: (纸本)9781632661067

Porous, nanostructured silver samples were produced using a direct-write method where a nanoparticle aerosol consisting of particles with a mean size of approximately 5 nm were accelerated to speeds of approximately 1000 m/sec and impacted onto a translating substrate [1]. The impacting particles have sufficient energy to stick to the substrate, allowing patterned thick films to be directly written from the aerosol without a mask. Unlike other low temperature processing routes for achieving patterned films, no organics are added that can interfere with post-deposition processing. Typical films are 5-100 μm thick, up to several centimeters long, and have an as-deposited relative densities as high as 70% of bulk Ag. Compression tests were carried out in steps at room temperature and at 150°C under constant displacement rates. Local strain and densification were measured by optical profilometry between each compression step. The results can be used as a starting point to better understand the mechanisms that govern plasticity, creep, and sintering in nanostructured, porous silver at low processing temperatures. © 2013 materials Research Society.

关键词： Room temperature

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Techno-economic and life-cycle assessment of electrochemical captured CO2 conversion process in monoethanolamine

Techno-economic and life-cycle assessment of electrochemical...

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2022 AIChE Annual Meeting

作者： Lee, Suhyun Choi, Woong Kim, Jae Hyung Hwang, Yun Jeong Na, Jonggeol Ewha Womans University School of Chemical Engineering and Materials Science Korea Republic of Ewha Womans University Graduate program in System Health Science and Engineering Korea Republic of Clean Energy Research Center Korea Institute of Science and Technology Korea Republic of Seoul National University School of Chemistry Korea Republic of Korea Republic of Ewha Womans University Dept. of Chemical Engineering & Material science Advanced Manufacturing Systems Laboratory Korea Republic of

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An Efficient Three-Factor Authenticated Key Agreement Technique Using FCM Under HC-IoT Architectures

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Computers, materials & Continua 2022年第7期72卷 1373-1389页

作者： Chandrashekhar Meshram Agbotiname Lucky Imoize Sajjad Shaukat Jamal Parkash Tambare Adel R.Alharbi Iqtadar Hussain Department of Post Graduate Studies and Research in Mathematics Jayawanti Haksar Government Post-Graduation CollegeCollege of Chhindwara UniversityBetul460001M.P.India Department of Electrical and Electronics Engineering Faculty of EngineeringUniversity of LagosAkokaLagos100213Nigeria Department of Electrical Engineering and Information Technology Institute of Digital CommunicationRuhr University44801BochumGermany Department of Mathematics College of ScienceKing Khalid UniversityAbhaSaudi Arabia Water Resources&Applied Mathematics Research Lab Nagpur440027India College of Computing and Information Technology University of TabukTabuk71491Saudi Arabia Mathematics Program Department of MathematicsStatistics and PhysicsCollege of Arts and SciencesQatar University2713DohaQatar

The Human-Centered Internet of Things(HC-IoT)is fast becoming a hotbed of security and privacy *** users can establish a common session key through a trusted server over an open communication channel using a three-party authenticated key *** of the early authenticated key agreement systems relied on pairing,hashing,or modular exponentiation processes that are computationally intensive and *** order to address this problem,this paper offers a new three-party authenticated key agreement technique based on fractional chaotic *** new scheme uses fractional chaotic maps and supports the dynamic sensing of HC-IoT devices in the network architecture without a password *** projected security scheme utilized a hash function,which works well for the resource-limited HC-IoT *** results show that our new technique is resistant to password guessing attacks since it does not use a ***,our approach provides users with comprehensive privacy protection,ensuring that a user forgery attack causes no ***,our new technique offers better security features than the techniques currently available in the literature.

关键词： Three-party authenticated key agreement anonymity fractional chaotic maps Chebyshev polynomial password table human-centered internet of things(HC-IoT)

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Dielectric Modulation of Two-Dimensional Dipolar materials

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Physical Review Letters 2019年第9期123卷 096101-096101页

作者： Ziwei Wang Erik Luijten Graduate Program in Applied Physics Northwestern University Evanston Illinois 60208 USA Departments of Materials Science & Engineering Engineering Sciences & Applied Mathematics and Physics & Astronomy Northwestern University Evanston Illinois 60208 USA

Spontaneous pattern formation plays an important role in a wide variety of natural phenomena and materials systems. A key ingredient for the occurrence of modulated phases is the presence of competing interactions, generally of different physical origins. We demonstrate that in dipolar films, a prototypical system for pattern formation, patterns can be induced by dielectric effects alone. A rich phase diagram arises, where striped and circular morphologies emerge with geometric properties that can be controlled through variation of particle shape and substrate permittivity or permeability. These effects are particularly enhanced by metamaterial substrates.

关键词： Classical statistical mechanics Dielectrics Electric polarization Pattern formation 2-dimensional systems Interfaces Monte Carlo methods

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Stabilization of hydroxyl-terminated silanes in porous silicon for in-situ DNA synthesis

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Physica Status Solidi (C) Current Topics in Solid State Physics 2011年第6期8卷 1851-1855页

作者： Lawrie, Jenifer L. Weiss, Sharon M. Interdisciplinary Graduate Program in Materials Science Vanderbilt University Nashville TN United States Department of Electrical Engineering and Computer Science Vanderbilt University Nashville TN United States

Passivation of porous silicon sensors is a critical issue for achieving high sensitivity and selectivity toward biomolecule targets that may be detected in complex physiologic solution. Without appropriate passivation, degradation of the porous silicon matrix inhibits the repeatability of optical measurements and limits applications in complex media. In this work, we present a method for stabilizing TEOS-HBA monolayers in porous silicon. Annealing of the silane at 200°C for 16 hours, followed by a deionized water wash for a minimum of one hour, results in a porous silicon surface that is highly stable in a number of solvents. Annealing improves cross-linking of surface-attached silane molecules for added stability, and hydrolyzing facilitates removal of weakly bound multilayers. This surface treatment procedure is of considerable interest in applications such as DNA synthesis where hydroxyl functionality is critical and a thick silane surface coating is not desired. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

关键词： Passivation

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Fabrication and photocatalytic activity of TiO2 composite membranes via simultaneous electrospinning and electrospraying process

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Journal of Environmental sciences 2018年第10期30卷 13-24页

作者： Taddao Pahasup-anan Kowit Suwannahong Wipada Dechapanya Ratthapol Rangkupan International Program in Hazardous Substance and Environmental Management Graduate School Chulalongkorn UniversityBangkok 10330Thailand Center of Excellence on Hazardous Substance Management (HSM) Bangkok 10330 Thailand Department of Public Health Faculty of Public Health Western UniversityKanchanaburi 71170 Thailand Department of Chemical Engineering Faculty of Engineering Ubonratchathani UniversityUbonratchathani 34190 Thailand Metallurgy and Materials Science Research Institute Chulalongkorn University Bangkok 10330 Thailand Nanotec-CU Center of Excellence on Food and Agriculture Chulalongkorn UniversityBangkok 10330 Thailand

In present study, a simultaneous electrospinning and electrospraying（SEE） process was employed to produce microclusters of TiO2 nanoparticles and interlock them in nanofibrous network. The photocatalytic composite membranes（PCMs） were fabricated by electrospraying TiO2 nanoparticle suspension into microcluster form that dispersed and entrapped within nylon-6 electrospun fiber membrane. Three PCMs membrane with TiO2 content of 52.0, 83.6,and 91.7 wt.% were successfully fabricated. The membrane consisted of TiO2 microclusters,ranging in sizes from around 0.3 to 10 μm, distributed uniformly within the nylon-6 nanofibrous network. PCMs photocatalytic activity against Methylene Blue（MB） in aqueous solution showed more than 98% MB removal efficiency after 120 min of photocatalytic oxidation（PCO） for all PCMs. For PCM with the highest TiO2 content tested for 5 PCO cycles, it was found that most of their TiO2 content remained incorporated within the nanofibrous structure. The concept of nanoparticles clusters entrapment with SEE fabrication employed here provide a simple and effective method for reducing detachment of nanostructure phase from nanocomposite membrane.

关键词： Nanocomposites Electrospinning Electrospraying TiO2 Photocatalysis

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Optimization Process of Glycerol Esterification Using Real Time Adaptive Control

Optimization Process of Glycerol Esterification Using Real T...

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International Conference on Advanced Computer science and Information Systems

作者： Iwan Aang Soenandi Ani Suryani Taufik Djatna Irzaman Post Graduate Program of Agro-industrial Technology Bogor Agricultural University Dramaga Indonesia Lecturer Faculty of Engineering and Computer Science Krida Wacana Christian University Post Graduate Program of Agro-industrial Technology Bogor Agricultural University. Dramaga Indonesia Post Graduate Program of Agro-industrial Technology and Graduate Program of Computer Science Bogor Agricultural University. Dramaga Indonesia Department of Physics Faculty Mathematics and Natural Sciences Bogor Agricultural University. Dramaga Indonesia

ISBN: (纸本)9781509003648

The synthesis reaction used in esterification needs high energy consumption and a precise processing time to get the best yield of target. In this study, a model was formulated to optimize glycerol esterification process by minimizing the time needed for the process and maximizing the yield of Mono-glycerides. This optimization has gained importance for boosting the esterification industry and improving the production efficiency. Optimization through adaptive monitoring and control has provided significant advances in the process efficiency, a lower energy consumption and a better product quality. This paper presents the optimization with a computational algorithm in real time and adaptive control (RTAC), as compared to the conventional (traditional) methods to monitor and control of glycerol esterification processes. The identification of esterification status based on temperature and time are evaluated to strengthen the optimization. An adaptive method as feature selection to select wavelength IR sensors at specified intervals was carried out with Relief algorithm and Adaptive Pillar K-means clustering method to set the parameter control was proposed in this paper. Many combinations were evaluated from real time condition process, to achieve the best optimization results. The experimental results demonstrate that real time adaptive control can be achieved by using three clusters, which are heating up, stabilizing and finishing. In RTAC, each cluster has its own parameter to set the control point by the servo motor that was attached to magnetic stirrer-heater. By using optimization parameter for each cluster, esterification process time can be shortened by 15-20 minutes with a higher yield (7% or more), lower range stirrer rotation (300rpm-450 rpm) and a lower final temperature of 200℃ - 210℃.

关键词： Optimization Real Time Adaptive Control Glycerol Esterification

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LZS/Al2O3 glass-ceramic composites sintered by fast firing

LZS/Al2O3 glass-ceramic composites sintered by fast firing

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作者： Arcaro, Sabrina Nieto, Maria Isabel Moreno, Rodrigo Salvador, Maria Dolores Borrell, Amparo Moreno, Berta Chinarro, Eva De Oliveira, Antonio Pedro Novaes Laboratory of Glass-Ceramic Materials VITROCER Federal University of Santa Catarina - UFSC Florianópolis SC88040-900 Brazil Graduate Program in Materials Science and Engineering - PGMAT Federal University of Santa Catarina - UFSC Florianópolis SC88040-900 Brazil Institute of Ceramics and Glass - CSIC Madrid Spain Institute of Materials Technology Polytechnic University of Valencia Spain

In this work, nanometric Al2O3 (1-5 vol.%) particles (13 nm, 100 m2/g) were added to a 19.58Li2O•11.10ZrO2•69.32SiO2 (mol%) (3.5 µm, 2.5 m2/g) parent glass-ceramic matrix to prepare composites with the purpose of studying the influence of Al2O3 on their structure, microstructure, mechanical, thermal and electrical properties when sintered by fast firing. The parent glass-ceramic was prepared by melting and fast cooling (in water) to obtain a glass frit. The resulting glass frit was milled according to a two-step procedure consisting on a dry milling stage followed by a long wet milling step down. Each composition was wet homogenized and then dried at 110 ºC for 48 h for disaggregation. The obtained powders were uniaxially pressed (100 MPa) and compacts sintered by fast firing (175 ºC/min) between 800 and 900 ºC for 30 min. The composites, with relative densities ranging from 89% to 93%, showed zircon and β-spodumene as main crystalline phases. The hardness and Young's modulus varied from 4.5 to 6.5 GPa, and from 65 to 102 GPa, respectively. The formation of β-spodumene in the obtained composites leads to reduce the CTEs, whose values ranged from 13 to 7 x 10-6 ºC-1 © 2017 Universidade Federal de Sao Carlos. All rights reserved.

关键词： Sintering

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Machine-learned molecular surface and its application to implicit solvent simulations

arXiv

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arXiv 2021年

作者： Wei, Haixin Zhao, Zekai Luo, Ray Departments of Materials Science and Engineering Molecular Biology and Biochemistry Chemical and Biomolecular Engineering and Biomedical Engineering Graduate Program in Chemical and Materials Physics University of California IrvineCA92697 United States

Implicit solvent models, such as Poisson-Boltzmann models, play important roles in computational studies of biomolecules. A vital step in almost all implicit solvent models is to determine the solvent-solute interface, and the solvent excluded surface (SES) is the most widely used interface definition in these models. However, classical algorithms used for computing SES are geometry-based, thus neither suitable for parallel implementations nor convenient for obtaining surface derivatives. To address the limitations, we explored a machine learning strategy to obtain a level-set formulation for the SES. The training process was conducted in three steps, eventually leading to a model with over 95% agreement with the classical SES. Visualization of tested molecular surfaces shows that the machine-learned SES overlaps with the classical SES on almost all situations. We also implemented the machine-learned SES into the Amber/PBSA program to study its performance on reaction field energy calculation. The analysis shows that the two sets of reaction field energies are highly consistent with 1% deviation on average. Given its level-set formulation, we expect the machine-learned SES to be applied in molecular simulations that require either surface derivatives or high efficiency on parallel computing platforms. © 2021, CC BY.

关键词： Solvents

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