Pub Date : 2020-09-29DOI: 10.33263/proceedings22.032032
We utilize ultrafast multi-pulse pump-push-probe transient absorption spectroscopy and time-resolved photoluminescence to monitor excited-state H-atom transfer from hydroxylic compounds to the heptazine derivative 2,5,8-tris(4-methoxyphenyl)-1,3,5,6,7,9,9b-heptaazaphenalene (TAHz). The heptazine moiety is structurally related to the monomer unit of the ubiquitous organic polymeric photocatalyst, carbon nitride. We show that TAHz can photochemically abstract an H-atom from water, in addition to generating H2 in aqueous suspensions with photocatalytic activity matching that of carbon nitride. In our multi-pulse experiment, we use resonant pump pulse to photoexcite TAHz to a bright high-lying excited state, and after a relaxation period of roughly 6 ps, we use a NIR (1150 nm) pulse to “push” the chromophore to a higher-lying excited state. When phenol is present, the push induces a persistent decrease (ΔΔOD) in the initial excited-state absorption, indicating the push pulse engenders a divergence in the photochemical branching ratios. In the presence of electron-donating substituted phenols, the magnitude of ΔΔOD diminishes markedly due to the increased excited-state reactivity of the complex accompanied by the cathodic shift in the phenol oxidation potential. Thus, the H-atom abstraction appears to proceed without aid from the additional energy of the push pulse. These results reveal new insight into the branching ratio among unreactive localized heptazine excited states and reactive intermolecular charge transfer states of H-bonded heptazine chromophores. More generally, this work provides new insight into molecular design strategies to control the excited-state photochemistry of aza-aromatic materials toward important reactions such as H-atom abstraction from water.
{"title":"Controlling Intermolecular H-atom Abstraction with Ultrafast Pump-Push-Probe Spectroscopy","authors":"","doi":"10.33263/proceedings22.032032","DOIUrl":"https://doi.org/10.33263/proceedings22.032032","url":null,"abstract":"We utilize ultrafast multi-pulse pump-push-probe transient absorption spectroscopy and time-resolved photoluminescence to monitor excited-state H-atom transfer from hydroxylic compounds to the heptazine derivative 2,5,8-tris(4-methoxyphenyl)-1,3,5,6,7,9,9b-heptaazaphenalene (TAHz). The heptazine moiety is structurally related to the monomer unit of the ubiquitous organic polymeric photocatalyst, carbon nitride. We show that TAHz can photochemically abstract an H-atom from water, in addition to generating H2 in aqueous suspensions with photocatalytic activity matching that of carbon nitride. In our multi-pulse experiment, we use resonant pump pulse to photoexcite TAHz to a bright high-lying excited state, and after a relaxation period of roughly 6 ps, we use a NIR (1150 nm) pulse to “push” the chromophore to a higher-lying excited state. When phenol is present, the push induces a persistent decrease (ΔΔOD) in the initial excited-state absorption, indicating the push pulse engenders a divergence in the photochemical branching ratios. In the presence of electron-donating substituted phenols, the magnitude of ΔΔOD diminishes markedly due to the increased excited-state reactivity of the complex accompanied by the cathodic shift in the phenol oxidation potential. Thus, the H-atom abstraction appears to proceed without aid from the additional energy of the push pulse. These results reveal new insight into the branching ratio among unreactive localized heptazine excited states and reactive intermolecular charge transfer states of H-bonded heptazine chromophores. More generally, this work provides new insight into molecular design strategies to control the excited-state photochemistry of aza-aromatic materials toward important reactions such as H-atom abstraction from water.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90764838","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 : 2020-09-27DOI: 10.33263/proceedings22.047047
In this study, the surface of TiO2 was coated with SiO2 and Al2O3 layers by sol-gel and chemical deposition methods. Firstly, the TiCl4 was magnetically stirred for 1 h in deionized water, and then the NaOH solution was drop wised to the solution and stirred 2h. Finally, the obtained TiO2 was washed, filtered, and dried in a vacuum oven. The surface of TiO2 was coated with SiO2 and Al2O3 layers subsequently by chemical deposition methods. The morphological, thermal, and crystal properties of products were determined via SEM, TGA, and XRD machines. The X-ray diffraction peaks displayed that the TiO2 nanoparticles were synthesized without any extra peaks. Moreover, the SiO2 and Al2O3 coated TiO2 particles contain extra SiO2 and Al2O3 peaks, indicating that the surface of TiO2 was coated via SiO2 and Al2O3. The SEM results displayed that TiO2 and SiO2 and Al2O3 coated TiO2 were spherical in shape, and the size distribution was found to be around 20-50 nm and 200-300 nm, respectively. The photocatalytic and UV–vis analyses were used to determine the CO2 reduction and optical properties of particles. The results showed that the absorption peaks were broad to longer wavelength with a coating of SiO2 and Al2O3. The CO2 reduction performance of TiO2 has been enhanced via coating SiO2 and Al2O3 layer.
{"title":"Photocatalytic CO2 Reduction and Thermal Properties of Alumina/Silica Coated TiO2 Nanoparticles","authors":"","doi":"10.33263/proceedings22.047047","DOIUrl":"https://doi.org/10.33263/proceedings22.047047","url":null,"abstract":"In this study, the surface of TiO2 was coated with SiO2 and Al2O3 layers by sol-gel and chemical deposition methods. Firstly, the TiCl4 was magnetically stirred for 1 h in deionized water, and then the NaOH solution was drop wised to the solution and stirred 2h. Finally, the obtained TiO2 was washed, filtered, and dried in a vacuum oven. The surface of TiO2 was coated with SiO2 and Al2O3 layers subsequently by chemical deposition methods. The morphological, thermal, and crystal properties of products were determined via SEM, TGA, and XRD machines. The X-ray diffraction peaks displayed that the TiO2 nanoparticles were synthesized without any extra peaks. Moreover, the SiO2 and Al2O3 coated TiO2 particles contain extra SiO2 and Al2O3 peaks, indicating that the surface of TiO2 was coated via SiO2 and Al2O3. The SEM results displayed that TiO2 and SiO2 and Al2O3 coated TiO2 were spherical in shape, and the size distribution was found to be around 20-50 nm and 200-300 nm, respectively. The photocatalytic and UV–vis analyses were used to determine the CO2 reduction and optical properties of particles. The results showed that the absorption peaks were broad to longer wavelength with a coating of SiO2 and Al2O3. The CO2 reduction performance of TiO2 has been enhanced via coating SiO2 and Al2O3 layer.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"310 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78109958","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 : 2020-09-27DOI: 10.33263/proceedings22.024024
Vibration energy harvester has been paid a lot of attention by many researchers to transforming ambient vibration into electrical energy, which is normally utilized to develop wireless electronic sectors. The paper presents a finite element model (FEM) of a vibration energy harvester consisting of a bimorph electromechanical system (MEMS) generator. The model is used to simulate, and compare, the mechanical characteristics and electrical response of piezoelectric material results between the cantilever beam structure formed by laminating two piezoelectric layers on both sides of a Carbon fiber reinforced polymer (CFRP) substrate and Ti-6Al-4V substrate using ANSYS®19 R1. A set of numerical simulations has been carried out, and the results show that the comparisons of the harmonic response analysis seen change between the different substrates based on the bimorph piezoelectric MEMS generator.
{"title":"Design, Analysis and Finite Element Modeling of Macro Fiber Composite Piezoelectric Materials","authors":"","doi":"10.33263/proceedings22.024024","DOIUrl":"https://doi.org/10.33263/proceedings22.024024","url":null,"abstract":"Vibration energy harvester has been paid a lot of attention by many researchers to transforming ambient vibration into electrical energy, which is normally utilized to develop wireless electronic sectors. The paper presents a finite element model (FEM) of a vibration energy harvester consisting of a bimorph electromechanical system (MEMS) generator. The model is used to simulate, and compare, the mechanical characteristics and electrical response of piezoelectric material results between the cantilever beam structure formed by laminating two piezoelectric layers on both sides of a Carbon fiber reinforced polymer (CFRP) substrate and Ti-6Al-4V substrate using ANSYS®19 R1. A set of numerical simulations has been carried out, and the results show that the comparisons of the harmonic response analysis seen change between the different substrates based on the bimorph piezoelectric MEMS generator.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"4 Obstet Gynaecol Sect 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77814099","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 : 2020-09-27DOI: 10.33263/proceedings22.007008
With the depletion of fossil sources, research is currently intensively focused on exploiting renewable ones. Particular attention is paid to wastes and raw materials for producing biodiesel, lubricants, surfactants, polymers, solvents, and fine chemicals [1-2]. In this area, heterogeneous catalysis plays a prominent role, due to the remarkable advantages of robustness and recyclability. A huge number of new heterogeneous nanocatalysts have been applied to exploiting biomass and raw materials [3,4]. Another sustainable approach flows chemistry, which has rapidly gained interest due to the advantages of automation, reproducibility, safety, and easy up-scale. Many applications to the synthesis of vegetable oil derivatives and waxes are reported [5,6].
{"title":"New Technologies and Processes Toward Sustainable Society","authors":"","doi":"10.33263/proceedings22.007008","DOIUrl":"https://doi.org/10.33263/proceedings22.007008","url":null,"abstract":"With the depletion of fossil sources, research is currently intensively focused on exploiting renewable ones. Particular attention is paid to wastes and raw materials for producing biodiesel, lubricants, surfactants, polymers, solvents, and fine chemicals [1-2].\u0000In this area, heterogeneous catalysis plays a prominent role, due to the remarkable advantages of robustness and recyclability. A huge number of new heterogeneous nanocatalysts have been applied to exploiting biomass and raw materials [3,4].\u0000Another sustainable approach flows chemistry, which has rapidly gained interest due to the advantages of automation, reproducibility, safety, and easy up-scale. Many applications to the synthesis of vegetable oil derivatives and waxes are reported [5,6].","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89865163","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 : 2020-09-27DOI: 10.33263/proceedings22.004005
Hierarchical Green-Energy Research Center aims to promote materials innovation of Li-ion battery (LIB) for electric scooter and MWh class energy storage. Our team has mainly developed strategies for material optimization and research methodology for the improvement of electric power and cyclic stability of LIB. Metal oxides are abundant in defect structures that determine electric conductance and electrochemical activity. The first principle calculation of lithium titanate (LTO) was applied to access the electronic structure of pristine LTO and aliovalent ion-doping LTO. The other oxides were chosen as nanostructured anode materials anchored on reduced graphene oxide. We found that their cyclic ability is significantly improved due to the structurally synergetic effect between oxide nanocrystallite and substrate; Si is regarded as one of the most popular anode materials for 3rd generation LIB, but its cycle life is still limited by an overgrowth of secondary electrolyte interface (SEI). Glucose-derived Si-O-C ligand in modified SEI possessed a high affinity to Li-chelation, thus alleviating volume expansion and structural instability. Electrolyte design is considered the current technical bottleneck for the implementation of high voltage LIB. An ionic liquid hybrid electrolyte has been demonstrated excellent oxidation potential of the carbonate solvent, resistance to Al corrosion, and potential of ~5.0 V (vs. Li+/Li) even at an operating temperature of 55oC. Another highlight in the center is gel polymer electrolyte (GPE) that enables enhancement of lithium-ion transference number of 0.57 by the existence of the imidazolium group. The newly designed GPE guaranteed effective Li+ pathways in electrolyte bulk and at electrode/electrolyte interfaces, a high potential of 5.4 V, and simplicity of electrolyte synthesis and all-solid-state battery assembly for industrial-scale production processes.
分层绿色能源研究中心旨在推动电动滑板车用锂离子电池(LIB)材料创新和兆瓦时级储能。我们的团队主要开发了材料优化策略和研究方法，以提高LIB的电力和循环稳定性。金属氧化物在决定电导率和电化学活性的缺陷结构中含量丰富。利用钛酸锂(LTO)的第一性原理计算获得了原始LTO和价离子掺杂LTO的电子结构。选择其他氧化物作为纳米结构阳极材料，锚定在还原氧化石墨烯上。研究发现，由于氧化物纳米晶与基体之间的结构协同作用，其循环能力显著提高;硅被认为是第三代锂离子电池最受欢迎的阳极材料之一，但其循环寿命仍然受到二次电解质界面(SEI)过度生长的限制。葡萄糖衍生的Si-O-C配体对li -螯合具有高亲和力，从而减轻了体积膨胀和结构不稳定性。电解液设计被认为是目前实现高压锂离子电池的技术瓶颈。离子液体混合电解质具有优异的碳酸盐溶剂氧化电位，耐铝腐蚀，即使在55℃的工作温度下也能达到~5.0 V (vs. Li+/Li)。中心的另一个亮点是凝胶聚合物电解质(GPE)，它可以通过咪唑基团的存在提高0.57的锂离子转移数。新设计的GPE保证了电解质体和电极/电解质界面上有效的Li+通路，5.4 V的高电位，以及工业规模生产过程中电解质合成和全固态电池组装的简单性。
{"title":"Li-ion Battery Research in Hierarchical Green-Energy Materials Research Center","authors":"","doi":"10.33263/proceedings22.004005","DOIUrl":"https://doi.org/10.33263/proceedings22.004005","url":null,"abstract":"Hierarchical Green-Energy Research Center aims to promote materials innovation of Li-ion battery (LIB) for electric scooter and MWh class energy storage. Our team has mainly developed strategies for material optimization and research methodology for the improvement of electric power and cyclic stability of LIB. Metal oxides are abundant in defect structures that determine electric conductance and electrochemical activity. The first principle calculation of lithium titanate (LTO) was applied to access the electronic structure of pristine LTO and aliovalent ion-doping LTO. The other oxides were chosen as nanostructured anode materials anchored on reduced graphene oxide. We found that their cyclic ability is significantly improved due to the structurally synergetic effect between oxide nanocrystallite and substrate; Si is regarded as one of the most popular anode materials for 3rd generation LIB, but its cycle life is still limited by an overgrowth of secondary electrolyte interface (SEI). Glucose-derived Si-O-C ligand in modified SEI possessed a high affinity to Li-chelation, thus alleviating volume expansion and structural instability. Electrolyte design is considered the current technical bottleneck for the implementation of high voltage LIB. An ionic liquid hybrid electrolyte has been demonstrated excellent oxidation potential of the carbonate solvent, resistance to Al corrosion, and potential of ~5.0 V (vs. Li+/Li) even at an operating temperature of 55oC. Another highlight in the center is gel polymer electrolyte (GPE) that enables enhancement of lithium-ion transference number of 0.57 by the existence of the imidazolium group. The newly designed GPE guaranteed effective Li+ pathways in electrolyte bulk and at electrode/electrolyte interfaces, a high potential of 5.4 V, and simplicity of electrolyte synthesis and all-solid-state battery assembly for industrial-scale production processes.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"514 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78847541","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 : 2020-09-27DOI: 10.33263/proceedings22.031031
Wood is a kind of material that humanity has used continuously since the day it existed. Wood materials that have been used in many areas of life in the historical process has also been preferred in handicrafts. Moreover, these materials have been used continuously in Turkish Handicrafts from past to present. Especially the Anatolian Seljuks showed original examples of wood materials art in works such as pulpit, mihrab, sarcophagus, lectern, door, and window wings. Kündekari and wood carving technique, which is a kind of interlacing technique in decoration, has been applied in walnut, ebony, rose, and oak wood materials. On the other hand, different surface coating processes such as painting and polishing were applied to these materials for decoration. Wood art continued to increase with wood carving techniques such as inlay, openwork bonding, tarsi, and Edirnekari in the Ottoman. There has been an increase in the variety of wood materials used with the increasing techniques. Hence, original wood samples were given in Ottoman wood art with a variety of materials and rich decoration techniques.
{"title":"The Development and Application of Wooden Materials in Turkish Arts","authors":"","doi":"10.33263/proceedings22.031031","DOIUrl":"https://doi.org/10.33263/proceedings22.031031","url":null,"abstract":"Wood is a kind of material that humanity has used continuously since the day it existed. Wood materials that have been used in many areas of life in the historical process has also been preferred in handicrafts. Moreover, these materials have been used continuously in Turkish Handicrafts from past to present. Especially the Anatolian Seljuks showed original examples of wood materials art in works such as pulpit, mihrab, sarcophagus, lectern, door, and window wings. Kündekari and wood carving technique, which is a kind of interlacing technique in decoration, has been applied in walnut, ebony, rose, and oak wood materials. On the other hand, different surface coating processes such as painting and polishing were applied to these materials for decoration. Wood art continued to increase with wood carving techniques such as inlay, openwork bonding, tarsi, and Edirnekari in the Ottoman. There has been an increase in the variety of wood materials used with the increasing techniques. Hence, original wood samples were given in Ottoman wood art with a variety of materials and rich decoration techniques.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90446706","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 : 2020-09-27DOI: 10.33263/proceedings22.026026
Photothermal therapy is an emerging method of cancer treatment in which tumors are ablated by heating agents using near-infrared light (700–1000 nm). A semiconductor with a bandgap between 0.3–0.7 eV would, therefore, efficiently emit near-infrared light. The new “magic” material graphene has a bandgap of zero, which is advantageous with regard to designing a new material with a suitable bandgap for the emission of near-infrared light. In our investigations, using the first-principles density functional theory calculation method, we aimed to and successfully designed graphene-based materials with a direct bandgap of 0.68 eV. They have the potential to be optimal and efficient near-infrared light sources due to their narrow yet fitting bandgap. The present results open up a new avenue for the application of graphene-based materials to assist in photothermal therapy.
{"title":"Near-Infrared Photothermal Therapy Cancer Treatment Assisted with Graphene-Based Materials","authors":"","doi":"10.33263/proceedings22.026026","DOIUrl":"https://doi.org/10.33263/proceedings22.026026","url":null,"abstract":"Photothermal therapy is an emerging method of cancer treatment in which tumors are ablated by heating agents using near-infrared light (700–1000 nm). A semiconductor with a bandgap between 0.3–0.7 eV would, therefore, efficiently emit near-infrared light. The new “magic” material graphene has a bandgap of zero, which is advantageous with regard to designing a new material with a suitable bandgap for the emission of near-infrared light. In our investigations, using the first-principles density functional theory calculation method, we aimed to and successfully designed graphene-based materials with a direct bandgap of 0.68 eV. They have the potential to be optimal and efficient near-infrared light sources due to their narrow yet fitting bandgap. The present results open up a new avenue for the application of graphene-based materials to assist in photothermal therapy.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86688576","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 : 2020-09-27DOI: 10.33263/proceedings22.027028
A great deal of attention has been given to the use of graphite in composite materials, taking advantage of their exceptional mechanical and electrical properties for developing electrochemical platforms and can also be easily modified, allowing the incorporation of different components. Various epoxy-graphite composites modified with benzoic acid, graphene oxide, and hydrotalcite were developed. The epoxy-graphite composites were characterized by cyclic voltammetry; electrochemical impedance spectroscopy, and field-emission scanning electron microscopy. The electrochemical behavior of the composites was analyzed from the reversibility of the Fe(CN)63-/Fe(CN)64- as a redox probe by the dependency of peak potential, the anode current relationship, and cathodic current with scan rate. Besides the advantage of being prepared by a simple and not costly procedure, the hydrotalcite-modified graphite-epoxy composite indicating the possible application of electrode for ionic exchange of positive species and potential for electroanalytical purposes; and the epoxy-graphite composite electrodes modified whit benzoic acid and graphene oxide offer both the possibility of obtaining electrochemical response at low concentrations of free DNA base and single DNA, and the required binding groups on the electrode surface for covalent immobilization of specific oligonucleotides. From the study of the electrochemical properties of epoxy-graphite composites, it was possible to determine: Lapachol, nitrogenous bases, oligonucleotides, single strands of Calf thymus DNA, and proviral DNA of HIV-1 in the clinical sample.
{"title":"Composite Epoxy-Graphite Materials and Their Electrochemical Application","authors":"","doi":"10.33263/proceedings22.027028","DOIUrl":"https://doi.org/10.33263/proceedings22.027028","url":null,"abstract":"A great deal of attention has been given to the use of graphite in composite materials, taking advantage of their exceptional mechanical and electrical properties for developing electrochemical platforms and can also be easily modified, allowing the incorporation of different components. Various epoxy-graphite composites modified with benzoic acid, graphene oxide, and hydrotalcite were developed. The epoxy-graphite composites were characterized by cyclic voltammetry; electrochemical impedance spectroscopy, and field-emission scanning electron microscopy. The electrochemical behavior of the composites was analyzed from the reversibility of the Fe(CN)63-/Fe(CN)64- as a redox probe by the dependency of peak potential, the anode current relationship, and cathodic current with scan rate. Besides the advantage of being prepared by a simple and not costly procedure, the hydrotalcite-modified graphite-epoxy composite indicating the possible application of electrode for ionic exchange of positive species and potential for electroanalytical purposes; and the epoxy-graphite composite electrodes modified whit benzoic acid and graphene oxide offer both the possibility of obtaining electrochemical response at low concentrations of free DNA base and single DNA, and the required binding groups on the electrode surface for covalent immobilization of specific oligonucleotides. From the study of the electrochemical properties of epoxy-graphite composites, it was possible to determine: Lapachol, nitrogenous bases, oligonucleotides, single strands of Calf thymus DNA, and proviral DNA of HIV-1 in the clinical sample.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"263 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76537469","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 : 2020-09-27DOI: 10.33263/proceedings22.025025
The unsurpassed mechanical properties of biomaterials stem from the intricate organization of inorganic and organic matter across length scales. In bone, water facilitates this organization, thereby playing an important structural role in addition to being a nutrient and waste transport medium. Water makes 10% of mammalian bone tissues and can be found in one of two states: bound (to the mineral phase) or mobile. While experimental studies were able to directly link the amount of bound water to bone strength, a molecular understanding of the interactions between the mineral (hydroxyapatite), organic (collagen) phase, and water is missing. In this talk, I will provide new insights into the water adsorption properties of bone tissues. I will present DFT calculations of water adsorption energy as a function of the environment, which includes an explicit solvent and human collagen fragments. I will show that the environment - rather than the mineral surface itself-governs the adsorption strength and mode. In particular, I will show that conditions consistent with aging tissues are associated with a lower density of adsorbed water molecules, which is a sign of weaker bones.
{"title":"Density Functional Theory Study of Bone Tissues: the Role of Water in Conferring Bone Strength","authors":"","doi":"10.33263/proceedings22.025025","DOIUrl":"https://doi.org/10.33263/proceedings22.025025","url":null,"abstract":"The unsurpassed mechanical properties of biomaterials stem from the intricate organization of inorganic and organic matter across length scales. In bone, water facilitates this organization, thereby playing an important structural role in addition to being a nutrient and waste transport medium. Water makes 10% of mammalian bone tissues and can be found in one of two states: bound (to the mineral phase) or mobile. While experimental studies were able to directly link the amount of bound water to bone strength, a molecular understanding of the interactions between the mineral (hydroxyapatite), organic (collagen) phase, and water is missing. In this talk, I will provide new insights into the water adsorption properties of bone tissues. I will present DFT calculations of water adsorption energy as a function of the environment, which includes an explicit solvent and human collagen fragments. I will show that the environment - rather than the mineral surface itself-governs the adsorption strength and mode. In particular, I will show that conditions consistent with aging tissues are associated with a lower density of adsorbed water molecules, which is a sign of weaker bones.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86913594","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 : 2020-09-27DOI: 10.33263/proceedings22.022022
The thermal expansion coefficient (CTE) of the copper element, which is widely used in the electronics industry, is quite high. It is of great importance to decrease the CTE value in order not to deform against the heat it is exposed to. In this study, it is aimed to theoretically examine the changes in CTE value when SiC supplement is applied to pure copper. For this purpose, CTE value calculations were made according to Kerner and Turner's models for composites that were reinforced at different rates by volume. Sample studies in the literature have been utilized for percent component ratios. In this context, the amount of reinforcement was adjusted to be 5, 10, 15, and 20vol.% by volume. According to the findings, it was observed that there was ̴ %4-17 decrease in CTE value based on the Kerner model and ̴ %7-26 decrease based on the Turner model.
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