Altering a polymer surface chemical structure by an ion-assisted reaction

A new surface modification technique, the so-called ion-assisted reaction (IAR), has been developed; such modification of polymer surfaces offers many industrial applications. The addition of new functional groups on polymer surfaces and permanent hydrophilic polymer surfaces (water contact angle below 30° and surface energy 60-70 mJ/m²) have been accomplished by IAR treatment. The formation of functional groups is significantly dependent on the flow rate of the reactive gas, the irradiating ion dose, and the ion beam energy. Improvements in wettability and surface energy are primarily attributed to the increase of polar characteristics due to the formation of functional groups such as —(C=O), —(C=O)—O—, —(C—O)—, etc. The characteristics of the IAR treatment have been reviewed, with outstanding results regarding the wettability and adhesion of various polymers such as PMMA, PC, PP, PS, PI, PVDF, and PTFE.     

Sensitivity of operating conditions and material properties for thermoforming process

Abstract

The thermoforming process involves three stages: sheet reheat; forming; and solidification. A polymeric sheet is heated in an oven to the desired forming temperature distribution. The sheet is then deformed to take the shape of the mould cavity and subsequently solidified. The deformation of the sheet is assisted by the application of a pressure differential and/or the use of a moving plug.     

Centrifugal casting of functionally graded aluminium matrix composite components

Abstract

Centrifugal casting is one of the potential manufacturing techniques used for producing near net shaped components with improved properties. The emergence of new class of functionally graded materials has made it an important technique for the fabrication of engineering components and structures with graded property. The present paper describes the studies carried out on processing and characterisation of functionally graded Al matrix composites components based on Al–SiC ex situ and Al–Si in situ composites. The microstructural and mechanical characteristics of the composites are evaluated. In the case of Al–SiC functionally graded metal matrix composites discs, the particles are segregated gradiently towards the outer periphery of the casting exhibiting high strength and hardness towards the outer periphery. The Al–Si in situ composite cylinder shows the dispersion of primary Si particles towards the inner periphery of the casting which can lead to higher hardness and wear resistance.     

Kinematic modeling,mobility analysis and design of wheeled mobile robots

Wheeled mobile robots (WMRs) consist of interconnections of many electromechanical systems. Their mechanical subsystem comprises primarily the platform and the wheel units. To formulate the kinematic model of this class of robots, we model the individual subsystems separately. The composite kinematic model of a WMR is then a coupling of the various kinematic submodels. We study WMRs with different wheels, i.e. offset wheels, centered wheels and dual-wheels. The study focuses on system mobility, which is derived using the functional matrix. We also identified the kinematic equivalence between the dual-wheel and the centered wheels, and some advantages of the dual-wheels over the centered wheels and offset wheels. Results suggest that WMRs with mobility less than 3 cannot track a trajectory with a discontinuous heading without incorporating a time delay, during which the wheel orientation should be changed. Moreover, the steering angles of WMRs equipped with steered wheels require proper coordination to avoid jamming of the drive subsystem. For design purposes, we aim at a kinetostatically robust WMR. The concept of kinetostatic isotropy is applied to find the location of the wheels with respect to the platform and their type in order to achieve isotropy. It is shown that WMRs with three conventional wheels can be made isotropic if the offset either vanishes or equals the radius of the wheel, and if the three wheels are mounted at the vertices of an equilateral triangle.     

Automated in situ hybridisation using Tecan robotics: a kick-start for Functional Genomics

High throughput parallel organic synthesis is now a common practice in discovery chemistry research. Argonaut's modular reaction cassette technology is aimed at parallel synthesis of focused small molecule libraries. The Trident™ automated platform has been designed to perform high throughput organic synthesis using this modular reaction cassette under truly inert conditions and in a robust, reproducible manner. This enables one to generate high quality libraries of small molecules and to access chemistry not normally amenable to automation.Recently we have introduced a Sample Processing Station (SPS), which enhances the upstream and downstream sample handling capabilities of the Trident™ platform. Enhanced software capabilities also provide the Trident™ synthesizer with powerful reaction development and optimization capabilities. Application of this technology in the synthesis of a small library of 1,2-diarylbenzimidazoles using solution-phase chemistry is presented. A number of product purification and isolation protocols using polymer-bound scavengers are discussed.     

DFT calculations for a photoresist polymer/TaO substrate adhesion in wafer fabrication

Using a density functional method, the adhesion characteristics of a photoresist polymer/TaO interface with and without impurities are investigated. A slab model is employed to study the importance of different TaO crystal faces. The results indicated that TaO (110) was the most important crystal face. Through geometry optimisation of the polymer on TaO (110), the effects of impurities including C, O, Si, NaOH and H₂O are analysed. It was found that majority of the impurities were harmful for the adhesion, especially Si, H₂O and OH, which should be removed during wafer fabrication process.     

Safety and the Prevention of Accidents

A form of accelerated corrosion test employing a humid atmosphere containing sulphur dioxide has been investigated. The permissible variations in sulphur dioxide concentration, relative humidity and temperature have been examined, and it is shown that the required conditions can be maintained by simple methods. 24 hr is a sufficiently long test period for most purposes. The corrosion pattern developed closely resembles that produced by outdoor exposure. Reproducibility of results at different times and in different laboratories is good. The test is suitable for testing a variety of coatings on steel, and may also be effective on other basis metals.     

Realization of a Multiple Object Rearrangement Task with Two Multi-Task Functional Robots

A rearrangement task of multiple objects is discussed here. In this paper, robots that carry more than one object simultaneously are referred to as multi-task functional, whereas a standard single-task robot carries one object at a time. With multi-task functional robots, the total length of transfer paths is shortened and the processing time is reduced. We propose a planning algorithm that consists of simulated annealing and a scheduling method using prioritization rules for a group of multi-task functional robots. We also propose a planning methodology on synchronization timing between the robots. Experiments involving two robots were conducted in real and simulated environments to show the effectiveness of the proposed algorithms.