Examination of HA230 turbine transition duct

Abstract

The present paper reports the results of an examination of a service run transition duct from one of Siemens' industrial gas turbines and the correlation between the findings for this, and those from the studies undertaken on laboratory exposed Haynes alloy 230 material. The studies have shown that there are changes in the microstructure and hardness of the material that can be related to temperature and time of exposure, and the information gained can lead to estimations of the average component operating temperature. Metallographic studies revealed a high level of heterogeneity of the grains in this transition duct.     

Visual Mark for Robot Manipulation and Its RT-Middleware Component

In this paper, a visual marker called Coded Landmark for Ubiquitous Environment (CLUE) is proposed for easy robot manipulation using the RT-middleware component technology. Currently, home service robots are being expected to work in human living environments; however, such environments might be highly complex for robots. One of the solutions to solve such problems might be the development of structured environments for robots, such as visual marks in human living space, which could often be used in industrial fields, e.g., marked lines for mobile robots in industry. For application of structured environments from the factory to the human living environment, the affinity to humans might be important, such as marks invisible to humans, but visible to robots. In this paper, an invisible marker, CLUE, which is based on QR codes, is proposed; this will provide robots with information on the objects that are to be manipulated and visual guidance required for robot manipulation based on the RT-middleware platform. Finally, by means of actual robot applications, the method to use the proposed robot technology component is shown.     

A Generic Architecture Multimedia Service and Management

A multimedia service architecture is constructedby using a generic component model. In order to derivespecific components, a generic service agent and genericservice component architectures are developed. Using generic agent and the service components,a TINA-C conformant object-oriented hierarchical genericservice component is developed and presented. As anexample, a multimedia QoS service and management architecture is presented.     

Role of Vertical Component of Surface Tension of the Droplet on the Elastic Deformation of PDMS Membrane

Poly(dimethylsiloxane) (PDMS) has been widely used in lab-on-a-chip and micro-total analysis systems (μ-TAS), thus wetting and electrowetting behaviors of PDMS are of great importance in these devices. PDMS is a kind of soft polymer material, so the elastic deformation of PDMS membrane by a droplet cannot be neglected due to the vertical component of the interfacial tension between the liquid and vapor, and this vertical component of liquid–vapor surface tension is also balanced by the stress distribution within the PDMS membrane. Such elastic deformation and stress distribution not only affect the exact measurement of contact angle, but also have influence on the micro-fluidic behavior of the devices. Using ANSYS code, we simulated numerically the elastic deformation and stress distribution of PDMS membrane on a rigid substrate due to the liquid–vapor surface tension. It is found that the vertical elastic deformation of the PDMS membrane is on the order of several tens of nanometers due to the application of a droplet with a diameter of 2.31 mm, which is no longer negligible for lab-on-a-chip and μ-TAS. The vertical elastic deformation increases with the thickness of the PDMS membrane, and there exists a saturated membrane thickness, regarded as a semi-infinite membrane thickness, and the vertical elastic deformation reaches a limiting value when the membrane thickness is equal to or thicker than such saturated thickness.     

Parametric approach to positional fault detection in short arc welding

Abstract

This work investigates a parametric technique for short arc welding fault detection. The independent component analysis algorithm is applied to split welding voltage and current signals into arcing and short circuiting regions. A series of parameters including means, medians and normalised inner products are calculated by processing the different sections of welding electrical data. Out of position welds in overlap joints are studied with investigation of the connection between parameters and short arc welding features. The effect of changing shielding gas is also illustrated. Figures of merit to quantify the change in various parameters between faulty and good welds are compared and discussed. It is shown that the data separation into two regions with independent component analysis is useful in providing various parameters that can assist in short arc welding fault detection under different conditions.     

Inverse gas chromatography investigation of the surface properties of cellulose

Cellulose samples differing in origin and crystallinity were examined by inverse gas chromatography (IGC). Surface energy characteristics such as the apparent dispersive component of the surface energy and acid-base properties, and also nanomorphology indices of the different cellulose samples, were assessed. The influence of humidity on these properties was demonstrated. A decrease of 10-20% of the interaction potential was detected. Crystalline cellulose is the most sensitive to the presence of adsorbed water, which possibly disorders its surface structure. IGC appears to be an appropriate method for the evaluation of the surface characteristics of cellulose. However, care has to be taken when trying to understand differences in surface properties between various cellulose samples, since IGC is very sensitive to minor variations in surface characteristics.     

Paper properties affecting pressure-sensitive tape adhesion

The interaction between paper and pressure-sensitive adhesive was investigated by peel adhesion testing. The paper/adhesive peel curves were analyzed by plotting the logarithm of the peak peel force (i.e. the maximum value) against the logarithm of the peel rate, yielding two linear segments: a peel-rate-dependent interfacial failure domain and a rate-independent paper failure domain. Three independent parameters were extracted from these plots, namely, the interfacial peel force (F _in) at a low peel rate of 1 mm/min, the maximum peel force (F _c) and the slope (S _p) in the plot of log (interfacial peel force) versus log (peel rate). The linkages between paper and its peel responses were analyzed using the multivariate statistical methods. The paper properties influencing peel force in interfacial failure domain were found to be primarily the paper surface chemistry, characterized by oxygen/carbon ratio (determined by XPS), and secondarily paper surface roughness. The peel force increased with oxygen/carbon ratio and with the surface roughness. The log–log slope in the interfacial failure domain was found to be independent of paper properties; it is determined by the adhesive rheology. The governing paper property in the paper failure domain was found to be the paper internal bond strength as measured by an internal (Scott) bond tester.     

A Photometric Study of the Thickness of Liquid Sheets Produced from Spinning Cups

An account is given of the way in which photometry may be utilized to measure the thickness of liquid sheets produced from spinning cup atomisers. The theory of the technique is discussed and its limitations are noted.