Papers by Keyword: Nanotechnology

Paper TitlePage

Authors: Gabriel Maia Kammer, Suelen Cristina Sartoretto, Rodrigo Resende, Marcelo Uzeda, Jhonathan Raphael Nascimento, Adriana Terezinha Alves, Jose Calasans-Maia, Alexandre Malta Rossi, J.M. Granjeiro, Mônica Diuana Calasans-Maia
Abstract: Bone tissue is a composite material that has hydroxyapatite (HA) as its main inorganic phase component. The biological apatites have low crystallinity and contain cationic and anionic substitutions in their structure, which differ from the available synthetic ceramics. The purpose of this study is to evaluate the biocompatibility of nanostructured carbonated hydroxyapatite microspheres containing 5 wt% strontium (SrcHA) compared with the biocompatibility of carbonated hydroxyapatite (cHA), both synthesized at 37°C and non-sintered, used to control stoichiometric HA microspheres in subcutaneous tissue of mice. The biomaterials (BM) were characterized using X-ray Diffraction (XRD), Vibrational Spectroscopy in an Infrared Fourier Transform (VSIRFT) and Scanning Electron Microscopy (SEM). Forty five balb-C mice were randomly divided into four groups of 15 animals each: SrcHA, cHA, HA, and without material implantation (Sham group). All samples were histologically processed for descriptive evaluation of the biological effect. At each experimental period (1, 3 and 9 weeks), there was a higher biosorption of the tested biomaterials observed in contrast with the HA. The cHA group was the only group completely phagocytosed by macrophages and giant cells after 9 weeks. All biomaterials proved to be biocompatible, and the cHA and SrcHA 3% groups exhibited a faster bioabsorption in comparison with the control group. The doping of strontium did not cause a greater biological response after the 3 experimental periods.
212
Authors: M. Girish Kumar, Prakash Vinod, P.V. Shashikumar
Abstract: Nanotechnology offers enormous potential for discovering new fundamental science, for creating new materials with unique and important properties, and for developing new technology. Nanotechnology deals with particles and system with dimensions of approximately 1 to 100 nanometers. Some aspects of nanomanufacturing technology facilities like nanofabrication, nanometrology requires extremely stable environment with very stringent limits of ground vibration. The ground vibrations induced due to road and rail traffic can affect the nanotechnology research activities, due to disturbances caused by the road and rail traffic induced ground vibrations on the nanotechnology processes and the measurements. The paper presents the study of road traffic and metro train induced ground vibration for establishment of nanomanufacturing technology facilities at CMTI. The road traffic and the metro train induced ground vibration were monitored inside the CMTI campus at surface level to identify the magnitude of ground vibration. The road traffic and the metro train induced ground vibrations are compared in comparison with the CMTI Nanotechnology Lab specifications. The metro train induced ground vibration levels are more in comparison to the road traffic induced ground vibration. The metro train induced ground vibration level exceeds the CMTI Nanotechnology Laboratory ground vibration specifications.
1991
Authors: K.Eric Drexler
Abstract: Proposed advanced mechanosynthetic systems [1] require molecular tools able to bind and transfer reactive moieties with high reliability at 300 K (failure rates << 10–10 per transfer operation). Screening of a large number of candidate tools at the AM1 level enabled the identification of a structure, DC10c, that is calculated (at the B3LYP/6- 31G(d,p) level) to meet these stringent requirements when used to transfer carbon dimers to any of a target class of graphene-, nanotube-, and diamond-like structures [2]. The favorable energy of transfer (exoergic by a mean energy ≥ 0.261 aJ per dimer) results from avoidance of the generation of high-energy radical sites during dimer release by means of π-delocalization to form a strained aromatic ring on the binding face of the empty structure. These energies are compatible with transfer-failure rates ~ 10–24 per operation at 300 K, and overall failure rates << 10–10.
867
Authors: Yu Qi Zheng, San Min Wang
Abstract: Microelectromechanical system (MEMS) and nanotechnology are important directions on the development of the science in twenty-first century. Some of the effects, such as viscous force, surface force, electrostatic force, friction etc., which can be usually ignored on the traditional scale, have become noticeable when the scale has turn to micro or nano scale. Nanotribology is one of the main areas of the indispensable researches on the basic theory and methodology of the effects. The micro/nano adhesive contact which is the foundation of nanotribology is studied in this paper. The earliest study on adhesive contact was done by Bradley. He presented an expression of adhesive force of two contacting rigid spheres. Derjaguin, Muller and Toprov (DMT) gave the relation of the contact area and the applied load of the adhesive contact of two spheres, but they did not consider the elastic deformation due to the adhesive force of the bodies. Johnson, Keudall and Roberts (JKR) provided a theory of the adhesive contact of two elastic spheres. Tabor gave a parameter (Tabor parameter) to interpret the ratio of the elastic deformation with the adhesive force of two contacting bodies. That is to say the DMT model corresponding to small Tabor parameter(<0.1) and the JKR model to large Tabor parameter(>5). Maguis gave a DMT-JKR transition using the Dugdale model in fracture mechanics (M-D model) in the intermediate region between the DMT model and the JKR model. A numerical algorithm of elastic adhesive contact based on the meshless method is presented in this paper. This make it possible to solve the adhesive contact with more complex surface topography and to consider more intricate factors, such as thermal stress, friction, elasto-plastic deformation etc. in the further studies on micro/nano scale adhesive contact problems. The meshless method seems to be a promising approach for contact analyses because of its flexibility in domain descritization and versatility in node arrangements. It can be used to solve a variety of complicated engineering problems. A numerical example of adhesive contact between a micro elastic cylinder and a rigid half-space is carried out to show the feasibility of the algorithm. In the simulation, an effective method of the M-D model is used to save the cost of computation. Compared with the existed solutions, the results solved by the presented algorithm are reasonable.
1251
Authors: Maxim S. Polyakov, Aram M. Badalyan, Vasily V. Kaichev, Igor K. Igumenov
Abstract: Metallic copper ultra-thin layers were synthesized by modified PE CVD method from low-sized volatile metal complexes consisting of small (2- to 5atomic) ligand molecules. To characterize the deposited copper layers the X-ray photoelectron (XPS), infrared (FTIR) and UV-vis spectroscopy, SEM, XRD analyses were used. The layers were found to be nanocrystalline and have a nanoscale grain structure with parameters depending on the experimental conditions. It was revealed that plasma activation decreases mean size of copper grains and increases its stability on the air. The microstructure of the layers was examined by scanning electron microscopy (SEM) and diffraction of synchrotron radiation (DSR) methods, and chemical composition with a predominant content of copper in the metallic state Cu0.
246
Authors: C.M. Nurulain, P.J. Ramadhansyah, A.H. Norhidayah
Abstract: This paper presents a review of nanoclay as a latest technology in order to overcome problem due deterioration such as rutting, fatigue, stripping, cracking and so on. Nowadays, with increasing of traffic volume and heavy vehicle conditions of existing road totally fail in order to accommodate this situation during design period. In order to manage this problem the new technology had been create and apply. Previous researches prove that nanotechnology has potential solution to enhance the performance and durability of construction materials. Material properties were characterized using Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). According to previous research there were proved that addition of nanoclay lead great improvements on permanent deformation and fatigue life of hot mix asphalt (HMA). In addition the overall performance of nanoclay as polymer modified asphalt binder was improve in terms of rutting and fatigue cracking resistance compare to non-modified asphalt binder. Therefore, nanoclay itself would be an alternative as modifier to use in the bitumen to improve the lifetime of asphalt pavements.
9
Authors: Abu Samah Nadzirah, Mahmood Rusop, A. Noriham
Abstract: In recent years much attention has been devoted to natural antioxidant which has shown health benefits to human. Most researchers propose that two-thirds of thirds of the worlds plant species have a medicinal value and a great antioxidant potential. Polygonum minus or kesum is a traditional Malaysian plant used as flavoring agent and recommended for digestive disorders as well as stomach pain. The leaves are often eaten fresh as a vegetable (salad and ulam), especially among the Malay communities for preventive health care. There is a several researchers have been reported that P. minus contains a high level of antioxidant activities. Therefore, P. minus was seen to have a potential and interesting plant for antioxidant evaluation. The aim of this study is to represent previous studies that have been conducted on P. minus for antioxidant activities and also to suggest a method to enhanced antioxidant activities using nanotechnology.
659
Authors: Tahereh Hasoomi, Sahar Mehraban
Abstract: The purpose of this project is to study the nanotechnology researchers’ information needs and information retrieval behavior. Its Methodology is questionnaire survey. Research instrument was a researcher-made questionnaire whose reliability was calculated through Cronbach α (α= 0,914) and whose content validity was analyzed and approved through expert opinions.1225 researchers in nanotechnology are included as the research population out of whom 291 researchers, based on Krejcie and Morgan table, were selected using cluster random sampling method. Out of distributed questionnaires (500), 243 of them (84% of the sample) were returned completed. Statistical analyses were carried out in SPSS and Excel environments. The results of research indicate that, 69.7 % researchers mainly use articles, 58.8 % of them e-journals, and a few of them use bibliographies as formal sources. Their ideal type of resource is e-resources. Their motives to use information are mainly conducting research projects and updating their field-related information. Academic centers are where they usually refer to address their information needs. The major problems to access information are inappropriate internet services and lack of access to certain data bases due to subscription issues.
3849
Authors: Jae Yeol Kim, Lee Ku Kwac, Jae Ho Han
Abstract: Recently, the world is preparing for new revolution, called, ‘IT(Information Technology), NT(Nano-Technology), and BT(Bio-Technology).’ NT can be applied to various fields such as semiconductor-micro technology. Ultra precision processing is required for NT in the field of mechanical engineering. Because of radical advancement of electronic and photonics industry, necessity of ultra precision processing is on the increase for the manufacture of various kernel parts. In this paper, stability of ultra precision cutting unit is investigated and this unit is the kernel unit in ultra precision processing machine. According to alteration of shape and material of hinge, stability investigation is performed. Hinge shapes of micro stage in UPCU (Ultra Precision Cutting Unit) are designed in two types, where, hinge shapes are composed of round and rectangularity. Elasticity and strength are analyzed on micro stage with respect to hinge shapes by FE analysis. The micro stage in ultra precision processing machine has to keep hinge shape under cutting condition with 3-component force (cutting component, axial component, and radial component) and to reduce modification against cutting force. Then we investigated its elasticity and strength under these conditions. The material of the micro stage is generally used for duralumin with small thermal deformation. Since the elasticity and the strength quiet become important, the stability of the micro stage is investigated. Used materials are composed of aluminum of low strength and cooper with medium strength and spring steel with high strength. Through this stability investigation, trials and errors are reduced in design and manufacture at the same time, and we are accumulated foundation data for a unit control.
591
Authors: Akira Kohyama
Abstract: As one of the most important breakthrough in the field of SiC/SiC composite materials, the new process called Nano-powder Infiltration and Transient Eutectoid (NITE) Process has been developed. The outstanding total properties of the NITE SiC/SiC composites are presented. Then, the current efforts to make attractive GFR based on the NITE SiC/SiC composites and the technology R & D to make reactor components with the NITE SiC/SiC composites are provided together with our efforts on innovative reactor designs.
16
Showing 1 to 10 of 171 Paper Titles