Erosion-corrosion of Fe- and Ni-based tubes and coatings in a fluidized bed test rig during exposure to HCl- and SO2-containing atmospheres

Tubes made from five commercial alloys (Fe9Cr1Mo, 304L, Esshete 1250, 353 MA and Inconel 625) as well as two coating materials (Inconel 625 and Metco 8443) deposited on low alloyed steel tubes were exposed to different atmospheres in a laboratory fluidized bed test rig at 550 °C for 3 weeks (504 h). The atmospheres were air, air + 50 ppm HCl and air + 50 ppm SO₂. Excluding the Metco 8443 coating, all materials show the lowest wastage rate in the SO₂-containing atmosphere. For all exposure conditions, the best overall performance is shown by the Fe9Cr1Mo alloy. The circumferential wastage profiles recorded on tubes exposed in air and air + 50 ppm HCl show an erosion pattern with two maxima (Type A behaviour), while the tubes recorded in the SO₂-containing atmosphere display only one maximum (Type B behaviour).     

Calibration of a planar laser induced fluorescence technique for use in large scale water facilities

A calibration process for planar laser induced fluorescence (PLIF) is presented and employed to investigate the mixing field of a co-flowing jet in a water channel flow. The calibration technique uses individual calibration curves for each pixel in the image array that correct for the non-uniformities of the laser sheet, optics and digital sensor and account for parameters that affect fluorescence efficiency of the dye. A unique commercial optic is introduced into the optical train to generate a thin laser sheet with an approximately uniform laser intensity distribution. The performance of the calibration procedure is investigated by analysis of the calibration data and through the investigation of a co-flowing jet. The results compare well with the results documented in the literature for this flow field. The work shows that the simple approach designed specifically for application in large-scale facilities is suitable for calibration of PLIF style techniques.     

Application of an envelope technique in the detection of ball bearing defects in a laboratory experiment

To judge the diagnostic capabilities of an envelope technique, based on enveloping the resonance frequency of a transducer,

1 Bearcon Signature™, Carl Schenck AG, Germany

artificially damaged ball bearings (SKF 6207) were run under oil lubrication at different radial loads and speeds in a laboratory experiment. Damage to the outer race, inner race and ball of different magnitudes was introduced by spark erosion and the response of the measurement system was analysed. The results showed that vibration spectrum components of outer race defects showed up in the envelope spectra of undamaged bearings, and that the detectability of defects was primarily limited by the speed of the bearing; on occasion the automatic scaling facility of the analyser was a limiting factor. Inner race and ball defects showed the well-known effects of load modulation in the defect contact zone, which can become dominant in the envelope spectra at high loads and speeds. This phenomenon could be confirmed by computer simulation. The detection of ball damage was hampered by the fact that overrolling of the defect in purely radially loaded bearings takes place incidentally. This drawback could be mitigated by applying a trigger technique to the envelope signal.     

A New Method of Non-Contact Measurement for Microtopography in Semiconductor Wafer Implementing a New Optical Probe Based on the Precision Defocus Measurement

In this paper, a new method of non-contact measurement has been developed for 3D topography for a semiconductor wafer, implementing a new optical probe based on precision defocus measurement. The developed technique consists of the new optical probe, precision stages, and the measurement/control system. The basic principle of the technique is to use the reflected slit beam from the specimen surface to measure the deviation of the specimen surface. The defocusing distance can be measured by the reflected slit beam, where the defocused image is measured by the proposed optical probe, giving very high resolution. A distance measuring formula has been proposed for the developed probe, using the laws of geometric optics. A precision calibration technique has been applied, giving about 10 nm resolution and 72 nm four-sigma uncertainty. In order to quantitise the micro pattern on the specimen surface, some efficient analysis algorithms have been developed to analyse the 3D topography pattern and some parameters of the surface. The developed system has been successfully applied to measure the wafer surface, demonstrating the line scanning feature and the excellent 3D measurement capability.     

触摸屏和PLC在风洞三维高精度移测控制系统中的应用

介绍了触摸屏和PLC在某风洞三维高精度移测控制系统中的应用和所要满足的控制要求,以及系统硬件结构和软件设计,并着重介绍了触摸屏的组态过程。实践验证,该系统满足设计要求,运行可靠。     

Adaptation of a super-sensitive epitope detection technique for the immunoelectron microscopy of titin filaments in vertebrate striated muscle

A super-sensitive epitope-detection technique based on gold–silver intensification was adapted for pre-embedding immunolabelling of titin filaments in vertebrate striated muscle. Indirect immunoelectron microscopy of titin filaments was performed with monoclonal titin antibodies as primary antibodies and F_ab anti-mouse IgG conjugated with 1.4 nm gold particles as secondary antibodies. The secondary antibodies penetrated easily into the tissue owing to their reduced size and the very small gold particles. After the labelling procedure, the tissue was fixed in glutaraldehyde. Since the gold particles were not visible by conventional transmission electron microscopy, they were intensified with a silver developing system. Although the particle size varied nonlinearly with the developing time, very fine grain size was achievable. The technique provided super-sensitive detection with excellent contrast and demonstrated epitopes with both strong and weak affinities.     

Potential of functional image processing technique for the measurements of contact area and contact pressure of a radial ply tire in a soil bin testing facility

The exploration principally deals with a promising applicability of image processing method for contact area determination. A digital camera mounted on a single-wheel tester was utilized to take images of contact area at four levels of tire inflation pressure (i.e. 70, 100, 140, and 175 kPa) and six levels of wheel load (i.e. 0.75, 1.75, 2.75, 3.75, 4.75, and 5.75 kN). Contact pressure measurements, subsequently, were performed utilizing seven embedded load cells incorporated in an instrumented housing in longitudinal and perpendicular direction of traversing. It was observed that contact area is a polynomial (with order of two) function of wheel load while there was a reverse linear relation between contact area and inflation pressure. Furthermore, contact pressure has linear relation with vertical load and inflation pressure. Models for contact area and contact pressure were developed by multiple regression analysis while a classical predicting model was assessed using contact area results of image processing technique. The models indicated acceptable coefficient of determinations amounts of 0.974 and 0.953 for contact area and contact pressure models, respectively. However, applied image processing method denoted R²-value of 0.988 for contact pressure equation.