Fabrication of nanoscale Ti honeycombs by focused ion beam

Ti honeycombs with the side of 800 and 400 nm were fabricated by focused ion beam (FIB), though the surfaces of the bottom and wall of the Ti honeycombs were rough, as compared with the surfaces of the bottom and wall of the Si honeycomb. It is demonstrated that the nanoscale Ti components can be fabricated in a short time by FIB.

Design, fabrication and evaluation of universal polymerase chain reaction devices

Novel and low cost PCR devices were developed to perform rapid polymerase chain reaction based diagnostics for infectious diseases. The main advantages of using these devices are that it can perform multi sample and also multiplexing of DNA samples woth low sample volume compared to the conventional PCR devices.

Fabrication of porous TiAl intermetallic compound by self-propagating high temperature synthesis

The present paper describes processing of a lotus-structured porous Ti-Al/Ti composite by SHS with Ti powder and Al rods. Ti-Al intermetallic compound was formed in a range of 200-300μm around the pore by SHS of reaction between Ti and Al, resulting in formation of a lotus-structured porous Ti-Al/Ti composite.

Detection of vehicles with monolithic classifier vis-à-vis a boosted cascaded classifier

This paper describes the comparison of accuracy and performance of two machine learning approaches for visual object detection and tracking vehicles, from an on-road image sequence. The first is a neural network based approach. Where an algorithm of multi resolution technique based on Haar basis functions was used to obtain an image with different scales. Thereafter a classification was carried out with the multilayer feed forward neural network. Principle Component Analysis (PCA) technique was used as a dimension reduction technique to make the classification process much more efficient. The second approach is based on boosting which also yields very good detection rates. In general, boosting is one of the most important developments in classification methodology. It works by sequentially applying a classification algorithm to reweighed versions of the training data, followed by taking a weighted majority vote of the sequence of classifiers thus produced. For this work, a strong classifier was trained by the adaboost algorithm. The results of comparing the two methodologies visà-vis shows the effectiveness of the methods that have been used.

Gaussian vault geometry : digital design and fabrication of scaled prototypes

This paper reports on three approaches to the translation of Gaussian surface models into scaled physical prototype models. Using the geometry of Eladio Dieste's Gaussian Vaults, the paper reports on the aspects encountered in the process of digital to physical prototype fabrication. The primary focus of the paper is on exploring the design geometry, investigating methods for preparing the geometry for fabrication and constructing physical prototypes. Three different approaches in the translation from digital to physical models are investigated: rapid prototyping, two dimensional surface models in paper and structural component models using Computer Numerical Controlled (CNC) fabrication. The three approaches identify a body of knowledge in the design and prototyping of Gaussian vaults. Finally the paper discusses the digital to. fabrication translation processes with regards to the characteristics, benefits and limitations of the three approaches of prototyping the ruled surface geometry of Gaussian Vaults.

Geometric and material constraints in parametric modelling : the design to fabrication process

Parametric modelling, commonly used in the automotive and aerospace industries, has recently been adopted in the architecture and construction fields. The ability to design small repeatable components and apply them to a larger governing surface geometry is one area of parametric modelling that has great design potential. This two level modelling control, of component and overall surface, can allow designers to explore new types of form generation subject to parametric constraints. This paper reports on the design to fabrication process using repeatable components over a governing or carrier surface. The paper reports on our study of the requirements and possible solutions for successfully controlling a repeatable element, known as a Representative Volumetric Element (RVE), using geometric parameters of a larger governing surface geometry and material properties. This modelling process, coupled with Rapid
Manufacturing (RM) and Computer Numerically Controlled (CNC) machines has the potential to significantly reduce the interface between design and fabrication.

Exploring the use of the tripeptide Gly–Gly–His as a selective recognition element for the fabrication of electrochemical copper sensors

The modification of electrodes with the tripeptide Gly–Gly–His for the detection of copper in water samples is described in detail. The tripeptide modified electrode was prepared by first self-assembling 3-mercaptopropionic acid (MPA) onto the gold electrode followed by covalent attachment of the tripeptide to the self-assembled monolayer using carbodiimide coupling. The electrodes were characterized using electrochemistry, a newly developed mass-spectrometry method and quantum mechanical calculations. The mass spectrometry confirmed the modification to proceed as expected with peptide bonds formed between the carboxylic acids of the MPA and the terminal amine of the peptide. Electrochemical measurements indicated that approximately half the MPA molecules in a SAM are modified with the peptide. The peptide modified electrodes exhibited high sensitivity to copper which is attributed to the stable 4N coordinate complex the peptide formed around the metal ion to give copper the preferred tetragonal coordination. The formation of a 4 coordinate complex was predicted using quantum mechanical calculation and confirmed using mass spectrometry. The adsorption of the copper to the peptide modified electrode was consistent with a Langmuir isotherm with a binding constant of (8.1 ± 0.4) 1010 M−1 at 25 °C.

Architecture of a biocompatible supramolecular material by supersaturation-driven fabrication of fiber network

The architecture of a biocompatible organogel formed by gelation of a small molecule organic gelator, N-lauroyl-l-glutamic acid di-n-butylamide, in isostearyl alcohol was investigated based on a supersaturation-driven crystallographic mismatch branching mechanism. By controlling the supersaturation of the system, the correlation length that determines the mesh size of the fiber network was finely tuned and the rheological properties of the gel were engineered. This approach is of considerable significance for many gel-based applications, such as controlled release of drugs that requires precise control of the mesh size. A direct cryo-transmission electron microscopy (TEM) imaging technique capable of preserving the network structure was used to visualize its nanostructure.

Fabrication and biofunctionalization of selenium-polypyrrole core-shell nanoparticles for targeting and imaging of cancer cells

Selenium-polypyrrole core-shell nanoparticles are fabricated by an in-situ polymerization process and functionalized with transferrin for targeting and imaging of human cervical cancer cells. The shell thickness and chemical composition of the as-synthesized particles can be manipulated by controlling the precursor concentration. The presence of the polymer layer can greatly increase the thermal stability of the selenium nanoparticles. The presence of transferrin molecules on the surface of the core-shell nanoparticles can significantly enhance their cellular uptake. The tranferrin-conjugated core-shell nanoparticles can be potentially used for the targeting and imaging of cancer cells.

Fabrication of ZnO/SiO2 composite nanospheres with high core-loading levels

Monodispersed silica shell / zinc oxide core composite nanospheres were prepared in an oil-in-water microemulsion system. By using cyclohexane as the oil phase and Triton X-100 as the surfactant, nanospheres with a high core loading level and high monodispersity were obtained. The silica coating greatly reduced the photoactivity of ZnO nanoparticles, offering safe and durable applications of ZnO as UV screening agents.

Gaussian vault geometry : integrated approach in design and fabrication of physical prototypes

This paper reports the second part of a study on the digital design and fabrication of scaled architectural prototypes. The first paper reported techniques in the realization of a double curved vault surface, the Gaussian Vault. The aims of the research here further extend this body of knowledge to a better understanding of constructible components. It addresses the problem of fabricating complex curved forms through the integration of the basic building elements, skin and structure, to achieve a scaled physical prototype. The focus of the experimentation is to investigate the process from which a digital surface form is conceived, to its preparation for fabrication and eventual construction in the fashion of a scaled model or workable prototype.