Pub Date : 2021-06-25DOI: 10.20998/2074-272x.2021.3.01
I. Yatchev, I. Balabozov, K. Hinov, I. Hadzhiev, V. Gueorgiev
Nowadays, the accelerated development of materials and technologies and the finding of new ones is a prerequisite for the improvement of well-known electromagnetic constructions used in various devices, as well as for the development of new ones. New construction of hybrid electromagnetic system with magnetic flux modulation (HEMSMM) is studied. The construction is composed of: ferromagnetic frame with air gaps, input and output coils and permanent magnets. Two input coils connected to the pulsed power supply are used to change the path of the generated by the permanent magnets constant magnetic flux. Input pulses with different shapes are applied to the input coils and signals in the output coils are obtained and compared. The main purpose of the work is to find the shape of the input pulses which leads to higher output power in comparison with the other shapes. Methods. Finite element method and COMSOL software is used for computer modelling of the proposed construction, where coupled electromagnetic field – electric circuit analysis is carried out. Results. A mathematical and numerical 3D model of new HEMSMM construction is realised and studied. The model allows to calculate and compare power efficiency of the studied device, when input pulses with different shapes are applied. Practical value. The developed computer model enables the study of the HEMSMM and other electromagnetic devices at different operating modes. It can be further improved and used in the search for optimal parameters of a particular electromagnetic device.
{"title":"Influence of the Shape of the Input Pulses on the Characteristics of Hybrid Electromagnetic System with Magnetic Flux Modulation","authors":"I. Yatchev, I. Balabozov, K. Hinov, I. Hadzhiev, V. Gueorgiev","doi":"10.20998/2074-272x.2021.3.01","DOIUrl":"https://doi.org/10.20998/2074-272x.2021.3.01","url":null,"abstract":"Nowadays, the accelerated development of materials and technologies and the finding of new ones is a prerequisite for the improvement of well-known electromagnetic constructions used in various devices, as well as for the development of new ones. New construction of hybrid electromagnetic system with magnetic flux modulation (HEMSMM) is studied. The construction is composed of: ferromagnetic frame with air gaps, input and output coils and permanent magnets. Two input coils connected to the pulsed power supply are used to change the path of the generated by the permanent magnets constant magnetic flux. Input pulses with different shapes are applied to the input coils and signals in the output coils are obtained and compared. The main purpose of the work is to find the shape of the input pulses which leads to higher output power in comparison with the other shapes. Methods. Finite element method and COMSOL software is used for computer modelling of the proposed construction, where coupled electromagnetic field – electric circuit analysis is carried out. Results. A mathematical and numerical 3D model of new HEMSMM construction is realised and studied. The model allows to calculate and compare power efficiency of the studied device, when input pulses with different shapes are applied. Practical value. The developed computer model enables the study of the HEMSMM and other electromagnetic devices at different operating modes. It can be further improved and used in the search for optimal parameters of a particular electromagnetic device.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87526346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-25DOI: 10.20998/2074-272x.2021.3.07
L. A. Ljutenko, V. M. Mikhailov
Purpose. An experimental verification of the existence of a range of values for the parameters of the capacitive energy storage of the magnetic-pulse installations with controlled vacuum discharger, in which, with a high probability, there is a «cut» of the discharge current pulses and the expansion of cylindrical thin-walled tubular workpieces using an external coil. Methodology. High voltage magnetic-pulse installation of NTU «KhPI» with controlled vacuum discharger, multiturn coil with inside dielectrical die and inside aluminum alloy workpiece are used. The capacitance and charge voltage of capacitive energy storage are changed. Discharge current pulses are measured by Rogowski coil and the oscillograph. Results. Parts of complicated shape are made by expansion of cylindrical tubular workpieces with help of external coil. Pressed metallic tubular part is removable from inner dielectric rod. Originality. The frequency of «cut» pulse is defined by negative magnetic field pressure amplitude. It is shown that we must coordinate this frequency and charge voltage with capacitive storage parameters by high probability of pulse «cut». Practical value. It is shown how to use installations with controlled vacuum dischargers in magnetic forming technology based on «cut» pulses.
{"title":"Expansion of Cylindrical Tubular Workpieces on High-Voltage Magnetic-Pulse Installation with Controlled Vacuum Discharger","authors":"L. A. Ljutenko, V. M. Mikhailov","doi":"10.20998/2074-272x.2021.3.07","DOIUrl":"https://doi.org/10.20998/2074-272x.2021.3.07","url":null,"abstract":"Purpose. An experimental verification of the existence of a range of values for the parameters of the capacitive energy storage of the magnetic-pulse installations with controlled vacuum discharger, in which, with a high probability, there is a «cut» of the discharge current pulses and the expansion of cylindrical thin-walled tubular workpieces using an external coil. Methodology. High voltage magnetic-pulse installation of NTU «KhPI» with controlled vacuum discharger, multiturn coil with inside dielectrical die and inside aluminum alloy workpiece are used. The capacitance and charge voltage of capacitive energy storage are changed. Discharge current pulses are measured by Rogowski coil and the oscillograph. Results. Parts of complicated shape are made by expansion of cylindrical tubular workpieces with help of external coil. Pressed metallic tubular part is removable from inner dielectric rod. Originality. The frequency of «cut» pulse is defined by negative magnetic field pressure amplitude. It is shown that we must coordinate this frequency and charge voltage with capacitive storage parameters by high probability of pulse «cut». Practical value. It is shown how to use installations with controlled vacuum dischargers in magnetic forming technology based on «cut» pulses.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88283147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-18DOI: 10.15587/1729-4061.2021.233182
A. Ramelan, Adhi Setyo Nugroho, T. Indriati, R. Rachmantyo
The development of potential alternative binders to Portland cement is still becoming a global challenge in housing and infrastructure aspects. That is because cement and concrete become the major materials needed in building constructions. The Ordinary Portland cement can form a solid and hard mass when mixed with water with a certain ratio. This is due to the formation of ettringite and calcium silicate hydrate (CSH) phases that contribute to the strength of the hydrated products about 33–53 MPa. However, the manufacturing temperature of Portland cement can reach up to 1,500 °C in producing clinker. In order to lower the energy consumption and production cost, scientists were trying to utilize pozzolanic materials. The research of pozzolanic materials as alkali-activated cement, such as soil cement or geopolymer cement, is also still conducted. Hence, a better understanding of pozzolanic reaction and its hydration products is needed. In this work, the hydration products of low-energy binders composed of Ca(OH)2-SiO2 and Ca(OH)2-metakaolin-gypsum mixtures were studied. The hydrated products of 41 wt. % Ca(OH)2 – 41 wt. % metakaolin – 18 wt. % gypsum mixtures followed by water immersion curing at 50 °C for 28 days undergone a pozzolanic reaction. XRD characterization showed that the hydrated product is mainly composed of ettringite (60.0 %) and crystalline-CSH (23.4 %). The diffractograms obtained have shown a specific hump indicating the presence of amorphous phases besides the crystalline. To confirm the presence of the non-crystalline or amorphous phases of the hydrated products, a polarizing optical microscope (OM) using a crossed Nicols method was used. The characterization of the phases is the novelty of the present research. The ettringite, crystalline CSH and the amorphous phases act as a strong binder that consequently contribute to its average maximum compressive strength of 22.17 MPa.
{"title":"Structural and Microscopy Characterization of an Alternative Low-Energy Binder Containing Ca(OH)2 as an Alkaline Activator","authors":"A. Ramelan, Adhi Setyo Nugroho, T. Indriati, R. Rachmantyo","doi":"10.15587/1729-4061.2021.233182","DOIUrl":"https://doi.org/10.15587/1729-4061.2021.233182","url":null,"abstract":"The development of potential alternative binders to Portland cement is still becoming a global challenge in housing and infrastructure aspects. That is because cement and concrete become the major materials needed in building constructions. The Ordinary Portland cement can form a solid and hard mass when mixed with water with a certain ratio. This is due to the formation of ettringite and calcium silicate hydrate (CSH) phases that contribute to the strength of the hydrated products about 33–53 MPa. However, the manufacturing temperature of Portland cement can reach up to 1,500 °C in producing clinker. In order to lower the energy consumption and production cost, scientists were trying to utilize pozzolanic materials. The research of pozzolanic materials as alkali-activated cement, such as soil cement or geopolymer cement, is also still conducted. Hence, a better understanding of pozzolanic reaction and its hydration products is needed. In this work, the hydration products of low-energy binders composed of Ca(OH)2-SiO2 and Ca(OH)2-metakaolin-gypsum mixtures were studied. The hydrated products of 41 wt. % Ca(OH)2 – 41 wt. % metakaolin – 18 wt. % gypsum mixtures followed by water immersion curing at 50 °C for 28 days undergone a pozzolanic reaction. XRD characterization showed that the hydrated product is mainly composed of ettringite (60.0 %) and crystalline-CSH (23.4 %). The diffractograms obtained have shown a specific hump indicating the presence of amorphous phases besides the crystalline. To confirm the presence of the non-crystalline or amorphous phases of the hydrated products, a polarizing optical microscope (OM) using a crossed Nicols method was used. The characterization of the phases is the novelty of the present research. The ettringite, crystalline CSH and the amorphous phases act as a strong binder that consequently contribute to its average maximum compressive strength of 22.17 MPa.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"136 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75044189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A numerical algorithm to evaluate acousto-optical nonreciprocity in multilayers was elaborated. Multilayer examples were designed to serve as transmission devices for the suppression of ring laser lock-in. The bias achieved turned out to be sufficient for typical HeNe-based ring laser gyros and surpassed the values reported for magneto-optical solutions. In addition, an acoustic dithering concept was developed to allow for an alternating bias and to reduce the power requirements of the device. A great choice of alternative acousto-optical materials makes the solutions equally suitable for integrated-optics gyros.
{"title":"Acousto-optical lock-in suppression for ring laser gyros: transmission device","authors":"J. Kaiser","doi":"10.2139/ssrn.3849196","DOIUrl":"https://doi.org/10.2139/ssrn.3849196","url":null,"abstract":"A numerical algorithm to evaluate acousto-optical nonreciprocity in multilayers was elaborated. Multilayer examples were designed to serve as transmission devices for the suppression of ring laser lock-in. The bias achieved turned out to be sufficient for typical HeNe-based ring laser gyros and surpassed the values reported for magneto-optical solutions. In addition, an acoustic dithering concept was developed to allow for an alternating bias and to reduce the power requirements of the device. A great choice of alternative acousto-optical materials makes the solutions equally suitable for integrated-optics gyros.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89908811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qilu Ye, Bingdi Yang, Gang Yang, Jiqing Zhao, Z. Gong
High entropy alloy (HEAs) are most likely to be the next-generation superalloy. However, the instability of solid solution, especially FCC type solid solution, in HEA limits the development of high entropy superalloys (HESAs). Due to the complex and large systems of HEAs and the lack of HEAs databases, the stability prediction of a solid solution in a HEA becomes a huge challenge. Here, Kinetic Monte Carlo simulation (KMC) was used to study the metastability in HEA, which required almost only parameters obtained from ab initio calculations rather than empirical HEAs databases. For the first time, the phase separation of AlCoCrFeMo0.05 N 2 alloy was predicted accurately by KMC method, showing that Al atoms preferentially occupied vacancies and eventually formed (Ni, Al)-rich phase. And the vacancies in the sample eventually formed a vacancy group in the (Ni, Al)-rich phase, promoting the transition of the phase from FCC to BCC structure.
{"title":"Stability Prediction of AlCoCrFeMo 0.05 N 2 High Entropy Alloy by Kinetic Monte Carlo Method","authors":"Qilu Ye, Bingdi Yang, Gang Yang, Jiqing Zhao, Z. Gong","doi":"10.2139/ssrn.3845646","DOIUrl":"https://doi.org/10.2139/ssrn.3845646","url":null,"abstract":"High entropy alloy (HEAs) are most likely to be the next-generation superalloy. However, the instability of solid solution, especially FCC type solid solution, in HEA limits the development of high entropy superalloys (HESAs). Due to the complex and large systems of HEAs and the lack of HEAs databases, the stability prediction of a solid solution in a HEA becomes a huge challenge. Here, Kinetic Monte Carlo simulation (KMC) was used to study the metastability in HEA, which required almost only parameters obtained from ab initio calculations rather than empirical HEAs databases. For the first time, the phase separation of AlCoCrFeMo0.05 N 2 alloy was predicted accurately by KMC method, showing that Al atoms preferentially occupied vacancies and eventually formed (Ni, Al)-rich phase. And the vacancies in the sample eventually formed a vacancy group in the (Ni, Al)-rich phase, promoting the transition of the phase from FCC to BCC structure.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87617697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jianglong Yan, D. Xia, Pa N. Xiong, Yangyang Li, Wenhao Zhou, Qiyao Li, Pei Wang, Qiyao Li, Yufeng Zheng, Yan Cheng
Abstract A well designed coating for polyetheretherketone (PEEK) implants can provide enough support to overcome crucial medical challenges, which are insufficient osseointegration and high rate of infection. Herein, we utilize the co-deposition of polydopamine (PDA) and copper-citrate nanoclusters to construct a pH-responsive coating on porous PEEK for synergistic bone regeneration, vascular formation and anti-infection. Specifically, this PDA coating released high dose of copper and citrate at lower pH value, which increased intracellular copper content, boosted production of reactive oxygen species and severe damage of protein, leading to killing of 93 % planktonic bacterial and eradication of adherent bacteria. At pH of 7.4, the release of copper and citrate were in a slow and sustained behavior, synergistically enhanced vascular formation potential and osteodiffereration of Ad-MSC in vitro. After implanted in rabbit tibia for 6 and 12 weeks, the micro-CT evaluation and histological analysis consistently highlighted the ability of this PDA coating to increase new bone formation adjacent to coated PEEK implant and enhance bone-implant interfacial integration. These results were proven to be related to the synergistic effect that citrate facilitated a 2-fold influx of copper into cells, which not only enhanced the bacteria-killing ability but also encouraged bone regeneration of implants. This present work provides an effective method to control infections while promoting osseointegration simultaneously, which will show tremendous clinical application and can be a solution to current challenges facing orthopedics.
{"title":"Polyetheretherketone with Citrate Potentiated Influx of Copper Boosts Osteogenesis, Angiogenesis, and Bacteria-Triggered Antibacterial Abilities","authors":"Jianglong Yan, D. Xia, Pa N. Xiong, Yangyang Li, Wenhao Zhou, Qiyao Li, Pei Wang, Qiyao Li, Yufeng Zheng, Yan Cheng","doi":"10.2139/ssrn.3600477","DOIUrl":"https://doi.org/10.2139/ssrn.3600477","url":null,"abstract":"Abstract A well designed coating for polyetheretherketone (PEEK) implants can provide enough support to overcome crucial medical challenges, which are insufficient osseointegration and high rate of infection. Herein, we utilize the co-deposition of polydopamine (PDA) and copper-citrate nanoclusters to construct a pH-responsive coating on porous PEEK for synergistic bone regeneration, vascular formation and anti-infection. Specifically, this PDA coating released high dose of copper and citrate at lower pH value, which increased intracellular copper content, boosted production of reactive oxygen species and severe damage of protein, leading to killing of 93 % planktonic bacterial and eradication of adherent bacteria. At pH of 7.4, the release of copper and citrate were in a slow and sustained behavior, synergistically enhanced vascular formation potential and osteodiffereration of Ad-MSC in vitro. After implanted in rabbit tibia for 6 and 12 weeks, the micro-CT evaluation and histological analysis consistently highlighted the ability of this PDA coating to increase new bone formation adjacent to coated PEEK implant and enhance bone-implant interfacial integration. These results were proven to be related to the synergistic effect that citrate facilitated a 2-fold influx of copper into cells, which not only enhanced the bacteria-killing ability but also encouraged bone regeneration of implants. This present work provides an effective method to control infections while promoting osseointegration simultaneously, which will show tremendous clinical application and can be a solution to current challenges facing orthopedics.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74299866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Gwalani, W. Fu, M. Olszta, J. Silverstein, Digvijay Yadav, Praveena Manimunda, A. Guzman, K. Xie, A. Rohatgi, S. Mathaudhu, Cynthia A. Powell, P. Sushko, Yulan Li, A. Devaraj
The starting alloy microstructure can be tailored to achieve varying degrees of grain refinement and enhance mechanical properties through severe plastic shear deformation during solid-phase processing. Crystal plasticity-based grain misorientation modeling, coupled with systematic pin-on-disk tribometry-based subsurface shear deformation experiments on as-cast Al-xSi alloys (x = 0, 1, 4 at %), was conducted. The post-deformation microstructural analysis, through a combined computational and experimental approach, conclusively shows that the initial volume fraction of the hard Si phase enhances the evolution of local lattice misorientation, leading to efficient grain refinement during severe plastic shear deformation. The shear-deformation–induced nanostructure resulted in more than double the nanoindentation hardness in the processed alloy.
通过固相加工过程中剧烈的塑性剪切变形，可以定制合金初始组织，实现不同程度的晶粒细化，提高力学性能。对铸态Al-xSi合金(x = 0,1,4 at %)进行了基于晶体塑性的晶粒取向错误建模和基于销盘摩擦学的亚表面剪切变形实验。通过计算和实验相结合的方法对变形后的显微组织进行分析，得出结论，硬Si相的初始体积分数增强了局部晶格取向错误的演变，导致在剧烈的塑性剪切变形过程中有效的晶粒细化。剪切变形诱导的纳米结构使加工合金的纳米压痕硬度提高了一倍以上。
{"title":"Lattice Misorientation Evolution and Grain Refinement in Al-Si Alloys Under High-Strain Shear Deformation","authors":"B. Gwalani, W. Fu, M. Olszta, J. Silverstein, Digvijay Yadav, Praveena Manimunda, A. Guzman, K. Xie, A. Rohatgi, S. Mathaudhu, Cynthia A. Powell, P. Sushko, Yulan Li, A. Devaraj","doi":"10.2139/ssrn.3820202","DOIUrl":"https://doi.org/10.2139/ssrn.3820202","url":null,"abstract":"The starting alloy microstructure can be tailored to achieve varying degrees of grain refinement and enhance mechanical properties through severe plastic shear deformation during solid-phase processing. Crystal plasticity-based grain misorientation modeling, coupled with systematic pin-on-disk tribometry-based subsurface shear deformation experiments on as-cast Al-xSi alloys (x = 0, 1, 4 at %), was conducted. The post-deformation microstructural analysis, through a combined computational and experimental approach, conclusively shows that the initial volume fraction of the hard Si phase enhances the evolution of local lattice misorientation, leading to efficient grain refinement during severe plastic shear deformation. The shear-deformation–induced nanostructure resulted in more than double the nanoindentation hardness in the processed alloy.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74579314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seok-Jin Kim, T. Kim, Ishfaq Ahmad, Hyuk‐Jun Noh, Sun-Min Jung, Yoon-Kwang Im, Javeed Mahmood, Youn‐Sang Bae, Jong‐Beom Baek
Two-dimensional (2D) fused aromatic networks (FANs) have a planar structure, in which planar building blocks are horizontally connected to form optimized, layered π-π stacking. Three-dimensional (3D) FAN structures, in which building blocks are divergently linked in the space, provide the maximum accessible internal surface area with permanent porosity. As sorbent materials, the confined layered stacking pattern of FANs restricts segmental motion; the available surface area is partially blocked by adjacent layers, resulting in relatively poor uptake kinetics and capacity. To understand the relationship between structure and sorbent performance, a new type of FAN structure with vertically standing structural units connected along the growth direction was designed and synthesized to minimize layer-to-layer interactions and maximize segmental freedom.
{"title":"Fused Aromatic Networks with the Different Spacial Arrangement of Structural Units","authors":"Seok-Jin Kim, T. Kim, Ishfaq Ahmad, Hyuk‐Jun Noh, Sun-Min Jung, Yoon-Kwang Im, Javeed Mahmood, Youn‐Sang Bae, Jong‐Beom Baek","doi":"10.2139/ssrn.3817756","DOIUrl":"https://doi.org/10.2139/ssrn.3817756","url":null,"abstract":"Two-dimensional (2D) fused aromatic networks (FANs) have a planar structure, in which planar building blocks are horizontally connected to form optimized, layered π-π stacking. Three-dimensional (3D) FAN structures, in which building blocks are divergently linked in the space, provide the maximum accessible internal surface area with permanent porosity. As sorbent materials, the confined layered stacking pattern of FANs restricts segmental motion; the available surface area is partially blocked by adjacent layers, resulting in relatively poor uptake kinetics and capacity. To understand the relationship between structure and sorbent performance, a new type of FAN structure with vertically standing structural units connected along the growth direction was designed and synthesized to minimize layer-to-layer interactions and maximize segmental freedom.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"100 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73633914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jie Liu, Xinwen Zhang, Ruoyu Wanga, Fei Long, Peng Zhao, Lei Liu
Abstract Superhydrophobic coatings can offer promising protection for metals against harsh service conditions. However, real applications are facing great challenges with the focus problem of lacking mechanical robustness. Current methods addressing this issue can not completely solve the problem or is not unsuitable for large-scale applications. Here, we propose an innovative strategy to fabricate a bioinspired superhydrophobic coating on 6061 Al via a simple and high-output route. By creating a mosquito-eye-like nanoframework-nanofiller structure with two different length scales, the coating is equipped with superhydrophobic property and excellent mechanical robustness, which are usually considered as two mutually exclusive properties. Based on a modified Cassie-Baxter model and a Gibbs interfacial energy model, a wetting theory is established to analyze the observed nonlinear change of the water contact angle, which suggests that the coating initially remains in the heterogeneous wetting state and abruptly transits to the intermediate wetting state. The theory further predicts the loss of anti-icing property upon abrasion, which is also confirmed by experiments. The superhydrophobic coating with robustness against abrasion will find its potential application values in complex service conditions.
{"title":"A Mosquito-Eye-Like Superhydrophobic Coating with Super Robustness against Abrasion","authors":"Jie Liu, Xinwen Zhang, Ruoyu Wanga, Fei Long, Peng Zhao, Lei Liu","doi":"10.2139/ssrn.3805218","DOIUrl":"https://doi.org/10.2139/ssrn.3805218","url":null,"abstract":"Abstract Superhydrophobic coatings can offer promising protection for metals against harsh service conditions. However, real applications are facing great challenges with the focus problem of lacking mechanical robustness. Current methods addressing this issue can not completely solve the problem or is not unsuitable for large-scale applications. Here, we propose an innovative strategy to fabricate a bioinspired superhydrophobic coating on 6061 Al via a simple and high-output route. By creating a mosquito-eye-like nanoframework-nanofiller structure with two different length scales, the coating is equipped with superhydrophobic property and excellent mechanical robustness, which are usually considered as two mutually exclusive properties. Based on a modified Cassie-Baxter model and a Gibbs interfacial energy model, a wetting theory is established to analyze the observed nonlinear change of the water contact angle, which suggests that the coating initially remains in the heterogeneous wetting state and abruptly transits to the intermediate wetting state. The theory further predicts the loss of anti-icing property upon abrasion, which is also confirmed by experiments. The superhydrophobic coating with robustness against abrasion will find its potential application values in complex service conditions.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87483087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiawei Fu, Kaiyu Zhu, X. Nie, Yuyuan Tang, Zefei Yang, L. Qi
Abstract The characterization of material anisotropic properties at high strain rates remains a challenging work due to the limitations of the conventional dynamic testing methods. In this study, a novel inverse identification strategy is proposed based on the dynamic virtual fields method (VFM) to enable a simultaneous identification of the anisotropic constitutive parameters from a single high speed impact test of a non-uniform specimen. This is implemented by taking advantage of the heterogeneous full-field strain and inertial acceleration data, in which the restrictions of one-dimensional stress wave propagation and homogeneous deformation states for the conventional methods are released. Specifically, the dynamic VFM-based identification algorithm is developed first. Then, several virtual impact tests with different specimen configurations are designed to provide distinct stress/strain distributions. Next, the simulated full-field strain and acceleration data are utilized to extract the input target orthotropic stiffness components. The results show that the identification accuracy of the anisotropic parameters is highly dependent on the heterogeneity of the stress/strain distributions. Also, the identification results are unstable for different time steps but can be significantly improved using a minimization algorithm on multiple time steps. Finally, the influences of noise, impact speed and loading mode are analyzed in the sensitivity study.
{"title":"Inertia-Based Identification of Elastic Anisotropic Properties for Materials Undergoing Dynamic Loadings Using the Virtual Fields Method and Heterogeneous Impact Tests","authors":"Jiawei Fu, Kaiyu Zhu, X. Nie, Yuyuan Tang, Zefei Yang, L. Qi","doi":"10.2139/ssrn.3805230","DOIUrl":"https://doi.org/10.2139/ssrn.3805230","url":null,"abstract":"Abstract The characterization of material anisotropic properties at high strain rates remains a challenging work due to the limitations of the conventional dynamic testing methods. In this study, a novel inverse identification strategy is proposed based on the dynamic virtual fields method (VFM) to enable a simultaneous identification of the anisotropic constitutive parameters from a single high speed impact test of a non-uniform specimen. This is implemented by taking advantage of the heterogeneous full-field strain and inertial acceleration data, in which the restrictions of one-dimensional stress wave propagation and homogeneous deformation states for the conventional methods are released. Specifically, the dynamic VFM-based identification algorithm is developed first. Then, several virtual impact tests with different specimen configurations are designed to provide distinct stress/strain distributions. Next, the simulated full-field strain and acceleration data are utilized to extract the input target orthotropic stiffness components. The results show that the identification accuracy of the anisotropic parameters is highly dependent on the heterogeneity of the stress/strain distributions. Also, the identification results are unstable for different time steps but can be significantly improved using a minimization algorithm on multiple time steps. Finally, the influences of noise, impact speed and loading mode are analyzed in the sensitivity study.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91082836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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