Laser-based cleaning

A particularly insidious failure mechanism that is commonly found in carbon-steel tubing is under-deposit corrosion. In many cases, corrosion products fomi a scab that can mask the presence of the pitting, making it difficult to quantitatively assess using conventional NDT methods. However, by combining proper cleaning procedures with laser-based inspection methods, the internal surface of the tubing can be accurately characterized and the presence of under-deposit corrosion can be confirmed and quantified. 

Spectral Sciences, Inc. Burlington, MA Development of diode laser-based remote monitoring of trace gas concentrations over long open-air paths. The target analytes include those covered by the Clean Air Act (CAA), formaldehyde among them. DOE... 

K ionophore sensor (61). To make -selective SECM tips, borosilicate capillaries (o.d./i.d. 1.0/0.58 mm) are cleaned in a 1 1 (v/v) mixture of concentrated sulfuric acid and 30% hydrogen peroxide overnight, washed and dried at 120 °C for 30 min. Using a laser-based pipette puller, patch clamp type pipettes are produced (orifice radius = 0.7-20 pm). The inner wall of each pipette is silanized with a toluene solution of trimethylchlorosilane (5-100% v/v). The solution is removed from the pipette after 5-30 min, emptied using a syringe, and then connected to a vacuum pump to remove any residual silanizing vapor. The experimental system can be represented by the following cell ... 

Experiments were conducted in our laboratory to evaluate many of the dynamical expectations for rapid laser heating of metals. One of the aims of this work was to identify those population distributions which were characteristic of thermally activated desorption processes as opposed to desorption processes which were driven by nontbennal energy sources. Visible and near-infrared laser pulses of nominally 10 ns duration were used to heat the substrate in a nonspecific fashion. Initial experiments were performed by Burgess etal. for the laser-induced desorption of NO from Pt(foil). Operating with a chamber base pressure 2 x 10 torr and with the sample at 200 K, initial irradiation of a freshly cleaned and dosed sample resulted in a short time transient (i.e. heightened desorption yield) followed by nearly steady state LID signals. The desorption yields slowly decreased with time due to depletion of the adsorbate layer at the rate of ca. 10 monolayer... 

Pacific Scientific Met One 210 Liquid Particle Counter is used to measure particles in clean fluids used in electronic, pharmaceutical and other manufacturing processes. It classifies particles in six size ranges in the 0.4 to 25 pm size range using laser diode based forward light scattering. Maximum count rate is 8000 particles per minute at a fluid flow rate of 100 ml min. ... 

Apart from obvious dry cleaning applications, potential applications of C02-based microemulsions include (i) printed circuit board cleaning, (ii) extraction of contaminants from soils, (Hi) cleaning of polymers, foams, aerogels, porous ceramics, and laser optics, (iv) regeneration of activated carbon beds or catalysts, and (v) the separation of dyestuffs from textiles. 

This goal is most clearly approached by methods based on vaporization of a metal by laser pulses, leading to a cloud of clean clusters of bare metal containing as few as one atom. Catalytic activity of clusters as a function of number of atoms can be obtained by time-of-flight mass spectrometry (16-18). 

As seen in this brief chapter, the direct-printing process, based on laser printing of layouts on polyester films or wax paper, has the potential to become a powerful technology for the rapid prototyping of microfluidic devices at very low cost, and even a source of low-cost production of disposable devices. This is supported by the fact that the required instrumentation is commonly found at offices and chemistry laboratories. Besides the typical injection and separation channels for electrophoresis, this technology has shown that mixing, preconcentration, clean-up, reactor devices. 

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