scholarly journals Zeolite-derived hybrid materials with adjustable organic pillars

2016 ◽  
Vol 7 (6) ◽  
pp. 3589-3601 ◽  
Author(s):  
Maksym Opanasenko ◽  
Mariya Shamzhy ◽  
Fengjiao Yu ◽  
Wuzong Zhou ◽  
Russell E. Morris ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Inorganic Materials ◽  
Top Down ◽  
Textural Characteristics ◽  
Different Types

Porous organic–inorganic materials with tunable textural characteristics were synthesized using the top-down process by intercalating silsesquioxanes and polyhedral oligomeric siloxanes of different types between crystalline zeolite-derived layers.

scholarly journals Monitoring morphology and properties of hybrid organicinorganic materials from in situ polymerization of tetraethoxysilane in polyimide polymer: 1. Effect of the coupling agent on the microstructure and interfacial interaction

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Hamid Kaddami ◽  
Carsten Becker-Willinger ◽  
Helmut Schmid
Keyword(s):  
Mechanical Properties ◽  
Hybrid Materials ◽  
Coupling Agent ◽  
In Situ Polymerization ◽  
Interfacial Interaction ◽  
Inorganic Materials ◽  
Hybrid Films ◽  
Morphological Transformation ◽  
Temperature Relaxation ◽  
Saxs Analysis

AbstractTransmission electron microscopy (TEM), small angle X-ray (SAXS) and dynamical mechanical thermal analysis (DMTA) were used to characterize the morphology and thermo-mechanical properties of hybrid organic inorganic materials. These materials were based on polyimide (PI) and tetraethoxysilane (TEOS). Polyimide polymer is prepared from 4,4’-oxydianiline (ODA) 2,2-Bis(3- amino-4-hydroxyphenyl) hexafluoro-propane (6F-OHDA) pyromellitic dianhydride (PMDA) polyamic polymer. In one family of hybrid materials 3- isocyanatopropyltriethoxysilane (ICTS) is used as coupling agent in order to enhance the interfacial interaction between polyimide and silica. It was possible to modulate the morphology as well as the optical and thermo-mechanical properties of these hybrid materials depending on the formulation used. TEM and SAXS analysis indicated that silica domains on the nanoscale level are obtained when coupling agent is used in the formulation. Additionally the TEM and SAXS analysis indicated that miscibility of the organic and the inorganic phases on the molecular scale is obtained in the hybrid films when ICTS as coupling agent is added to the polyamic acid. These techniques show a fractal structure of the hybrid materials with coupling agent. This was confirmed with DMTA analysis which shows very high temperature relaxation (more than 450°C). From this result it could be derived that the addition of ICTS causes a morphological transformation from discrete particulate microstructure to fine interpenetrated or co-continuous phases. The intimate miscibility of the phases is accompanied at the same time by the amelioration of thermo-mechanical properties of the hybrid films.

Springback Analysis in Hybrid Material Deformation

2018 ◽  
Author(s):  
Elizabeth M. Mamros ◽  
Chetan P. Nikhare
Keyword(s):  
Hybrid Materials ◽  
Material Properties ◽  
Shape Change ◽  
Single Layer ◽  
Metal Composite ◽  
Composite Sandwich ◽  
Composite Layers ◽  
Different Types ◽  
Reduction Methods ◽  
Manufacturing Problems

In the automotive and aerospace industries, cost and overall weight are major opponents that are affecting design opportunities. Research to investigate possible cost and weight reduction methods is continuously being performed focusing especially on the hybrid materials being used to manufacture parts. Currently, different types of metals with polymers are being chosen to make punched parts, but the deformation of the materials has not been fully investigated. The way that the material deforms will dictate the material properties held by the subsequent parts. Without knowing these material properties, it is difficult to prevent manufacturing problems during various processes. One major problem encountered when forming solid metal parts is that when the die is removed, the deformed parts change shape due to the elastic properties of the material. This shape change is called springback. This undesirable result causes the parts to be the incorrect shape and to not align correctly during assembly. One possible solution would be to investigate the material properties of trilayer hybrid materials consisting of metal and composite layers adjoined by adhesive. Trilayer channels will be tested by punching and measuring the resulting springback. Two different trilayer design setups will be tested, composite metal composite sandwich and metal composite metal sandwich, and will be compared with the deformation in a single layer metal channel. The outcome of these tests will determine which trilayer design will have the greatest success in reducing the undesirable springback effects.

Tribological Investigation of Nanographite Platelets as Additive in Anti-Wear Lubricant: A Top-Down Approach

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Flavio A. C. Vidal ◽  
Antonio F. Ávila
Keyword(s):  
Friction Coefficient ◽  
Friction Reduction ◽  
Wear Properties ◽  
Top Down ◽  
Base Oil ◽  
Graphene Layers ◽  
Sliding Mechanism ◽  
Wear And Friction ◽  
Different Types ◽  
Mineral Base

A top-down approach is employed to investigate the tribological effect of adding nanographite platelets (NGPs) to mineral base oil (MBO). The performance of the NGP-modified MBO was evaluated by examining the friction and anti-wear properties. Four different types of NGPs produced by two different processes were employed. The optimal NGP-modified MBO attained a significant wear and friction reduction when compared with the MBO without NGPs. The process used to exfoliate the graphite nanoplatelet samples provided better wear properties because of the graphene layers' smoother sliding mechanism. Graphene layers seeped inside the groove marks to keep the friction coefficient low.

Manufacturing of two and three-dimensional micro/nanostructures by integrating optical tweezers with chemical assembly

Robotica ◽  
2005 ◽  
Vol 23 (4) ◽  
pp. 435-439 ◽  
Author(s):  
Kenneth Castelino ◽  
Srinath Satyanarayana ◽  
Metin Sitti
Keyword(s):  
Optical Tweezers ◽  
Manufacturing System ◽  
Three Dimensional ◽  
Inorganic Materials ◽  
Top Down ◽  
Bottom Up ◽  
Complementary Dna ◽  
Nanoscale Manufacturing ◽  
2D And 3D

Optical tweezers have been used as versatile tools for non-contact manipulation of micrometer-sized entities. This paper proposes a hybrid micro/nanoscale manufacturing system using optical tweezers and chemical linkages for fabricating 2D and 3D micro/nanostructures. A holographic multiple trap optical tweezers system is first used to trap particles in a desired pattern. The particles are then connected to form rigid units using suitable chemistry. Connection schemes based on gold seeding, complementary-DNA linkage and streptavidin-biotin chemistry are presented and possible applications of this technique are explored. This method combines the advantages of top-down and bottom-up approaches and is compatible with organic and inorganic materials.

State Complexity of Regular Tree Languages for Tree Matching

2016 ◽  
Vol 27 (08) ◽  
pp. 965-979
Author(s):  
Sang-Ki Ko ◽  
Ha-Rim Lee ◽  
Yo-Sub Han
Keyword(s):  
The State ◽  
Top Down ◽  
Matching Problem ◽  
Tree Language ◽  
State Complexity ◽  
Regular Tree ◽  
Language L ◽  
Different Types ◽  
Tree Languages

We study the state complexity of regular tree languages for tree matching problem. Given a tree t and a set of pattern trees L, we can decide whether or not there exists a subtree occurrence of trees in L from the tree t by considering the new language L′ which accepts all trees containing trees in L as subtrees. We consider the case when we are given a set of pattern trees as a regular tree language and investigate the state complexity. Based on the sequential and parallel tree concatenation, we define three types of tree languages for deciding the existence of different types of subtree occurrences. We also study the deterministic top-down state complexity of path-closed languages for the same problem.

scholarly journals Action Research as a Bottom-up Approach to Foster Teacher Involvement in Language Curriculum Change

2017 ◽  
Vol 8 (2) ◽  
pp. 362
Author(s):  
Mina Saghaieh Bolghari ◽  
Arezoo Hajimaghsoodi
Keyword(s):  
Professional Development ◽  
Action Research ◽  
Curriculum Development ◽  
Curriculum Change ◽  
Teacher Involvement ◽  
Top Down ◽  
Language Curriculum ◽  
Different Types ◽  
Basic Characteristics

Despite the popularity of action research in the field of teacher education and professional development, not much is found regarding the role of action research in language curriculum development. This lack of interest may stem from the dominance of top-down approach over curriculum development in some EFL contexts where no special place is given to the local needs and wants. This paper starts with the definition and some basic characteristics of action research and then follows with a brief overview of its origins as well as different types. How action research can make changes in a curriculum is discussed next. Then it looks at the role action research may play in creating positive changes in teachers’ roles in curriculum development. Some of the challenges of implementing action research are mentioned later. Finally, the paper ends with some guidelines for teachers to make improvements as a result of conducting action research.

scholarly journals O USO DE MATERIAIS HIBRIDOS OU NANOCOMPÓSITOS COMO REVESTIMENTOS ANTICORROSIVOS DO AÇO

Química Nova ◽  
2021 ◽  
Author(s):  
Guilherme Clemente ◽  
Gustavo Gonçalves ◽  
Eduardo Nassar ◽  
Eduardo Molina ◽  
Lucas Rocha
Keyword(s):  
Hybrid Materials ◽  
Nanocomposite Materials ◽  
Exploratory Research ◽  
Metallic Surfaces ◽  
Metallic Material ◽  
Functional Loss ◽  
Anticorrosive Coatings ◽  
Different Types

THE USE OF HYBRID OR NANOCOMPOSITE MATERIALS AS STEEL ANTICORROSIVE COATINGS. The search had as the goal to present and reflect the hybrid materials as an alternative for anticorrosive coatings of metallic surfaces, such as steel. For comparison purposes, different types of anti-corrosion coatings capable of protecting metallic surfaces, such as steel, from oxidation action were presented. Steel is a metallic material widely used by industry in different types of segments, and its corrosion is a pathology responsible for its functional loss, causing losses in its use. Through a qualitative, bibliographic and exploratory research, based on academic works, it was presented that hybrid materials or nanocomposites prove to be efficient as anticorrosive coatings capable of protecting steel against oxidation.

scholarly journals Modification of Diamagnetic Materials Using Magnetic Fluids

2020 ◽  
Vol 65 (9) ◽  
pp. 751
Author(s):  
I. Safarik ◽  
J. Prochazkova ◽  
E. Baldikova ◽  
M. Timko ◽  
P. Kopcansky ◽  
...  
Keyword(s):  
Smart Materials ◽  
Magnetic Fluids ◽  
Polymer Gels ◽  
Relevant Information ◽  
Inorganic Materials ◽  
Magnetic Iron Oxide Nanoparticles ◽  
Magnetic Separator ◽  
Environmental Technology ◽  
Different Types ◽  
Magnetic Modification

Magnetic fluids (ferrofluids) have found many important applications in various areas of biosciences, biotechnology, medicine, and environmental technology. In this review, we have summarized the relevant information dealing with a magnetic modification of diamagnetic materials using different types of ferrofluids. Special attention is focused on a magnetic modification of plant-derived biomaterials, microbial and microalgal cells, eukaryotic cells, biopolymers, inorganic materials, and organic polymers. Derivatization is usually caused by the presence of magnetic iron oxide nanoparticles within the pores of treated materials, on the materials surface or within the polymer gels. The obtained smart materials exhibit several types of responses to an external magnetic field, especially the possibility of the selective magnetic separation from difficult-to-handle environments by means of a magnetic separator. The ferrofluid-modified materials have been especially used as adsorbents, carriers, composite nanozymes or whole-cell biocatalysts.

A Design Procedure Applicable to Different Classes of Assemblies

2001 ◽  
Author(s):  
Daniel E. Whitney ◽  
Gaurav Shukla ◽  
Stefan von Praun
Keyword(s):  
Design Process ◽  
Design Procedure ◽  
Kinematic Structure ◽  
Top Down ◽  
Design Decisions ◽  
Cad Systems ◽  
Mechanical Assemblies ◽  
Different Types ◽  
Comprehensive Classification

Abstract One of the most difficult problems which designers of complex mechanical assemblies face routinely is not to be aware of when they are committing mistakes. More and more dependence of designers on CAD systems further aggravates the problem of committing the mistake of not giving proper attention to the kinematic structure of the assembly. This article presents design phases for assemblies according to a top-down design process and the generic steps that constitute different design phases. A comprehensive classification of mechanical assemblies follows the outline of the steps of the design process. This classification also defines the characteristics of different types of assemblies and most importantly it identifies the possible mistakes that designers may commit. A separate classification of different procedures for meeting assembly tolerances is also presented. This article will not only talk about the classifications but it will also enlist information about various techniques that can be used to analyze different types of assemblies. Together, these sets of classifications outline a comprehensive design procedure that will help designers of assemblies in making sure that they justify their design decisions. This paper also links the steps in the design process to specific tools developed in previous papers.

Energy Filtering Transmission Electron Microscopy of Polymers and Hybrid Materials

1999 ◽  
Vol 5 (S2) ◽  
pp. 628-629
Author(s):  
Alexander Du Chesne ◽  
Ralph Ulrich ◽  
Ulrich Wiesner
Keyword(s):  
Block Copolymers ◽  
Hybrid Materials ◽  
Interfacial Area ◽  
Inorganic Materials ◽  
Solution Temperature ◽  
Mixing Enthalpy ◽  
Structure Directing Agent ◽  
Selective Staining ◽  
Energy Filtering ◽  
Covalently Linked

A topic of growing importance is the nano-structuring of inorganic materials by exploiting interactions with self assembling polymers. One example are multiphase polymers.Driven by the mixing enthalpy, most polymers phase separate below their critical solution temperature. The components of block copolymers are covalently linked, restricting separation to microscopic length scales. Depending on composition, block copolymers form different equilibrium morphologies representing the energetically most favorable balance between- interfacial area and chain conformation.Mass thickness contrast of polymers is often weak and conventional TEM can thus fail to characterize the morphology unless selective staining methods exist. This is the case for the poly(isoprene)-b-poly(ethyleneoxide) diblock copolymer system (PI-b-PEO) used as a structure directing agent and to provide solubility (see below). Fig. 1 shows the micro-domain morphology of PI-b-PEO where the rubbery phase is selectively stained with OsO4 .Hybrid materials are obtained by addition of an inorganic precursor to a solution of PI-b-PEO in a "mutual" solvent.

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