Cleaning characteristics

The segregation of solvent and paint wastes to avoid the formation of azeotropes to maintain the cleaning characteristics of the recycled solvent and... 

The added surfactant molecules intended for CMP slurry stabilization can adsorb not only onto the abrasive particle but also onto the surface of the wafer to be polished. Depending on the extent of such adsorption, the added surfactant may influence the CMP process in several ways such as change in friction behavior of the slurry, modification of removal rate and selectivity, alteration of defectivity level, and shift in post-CMP profile. In this section the impact of surfactant adsorption on the removal rate, selectivity, and post-CMP cleaning characteristics will be discussed. 

It is important to understand the adhesion force of particles on polished surfaces, which can be correlated with the polishing and cleaning characteristics of a CMP process. Higher adhesion force often leads to higher polishing rate, higher level of scratches, and greater number of particles left on the polished surface. 

To compare the cleaning characteristics of supercritical carbon dioxide with that of air, we have plotted in Fig. 8 the radius of the smallest particle (in the range of a few microns) that can be removed with air at 1 atmosphere and a temperature of 300 K. It shows that even for a relatively high velocity of 1000 cm/s, the minimum radius is 0.2 microns. This may be compared to 0.005 microns for supercritical CO2. Requirements of such fast flow for air will probably force the use of jets. This raises an additional complication of having to install a mechanism to sweep the wafer clean. The sweeping motion will most certainly lead to additional contamination from lubricated joints, etc. Such complications do not arise for the case of supercritical CO2, given the relatively low velocities needed. 

Although soft dry pet foods have a highly palatable soft texture, they do not provide the desirable teeth-cleaning characteristics of a conventional dry pet food. Bone and Shannon (1977a) thus developed a dry pet food, which contained both a soft dry pet food component and a hard dry pet food component the product had both a soft... 

Jackson, A.T., 1984, Cleaning characteristics of a plate heat exchanger fouled with tomato paste using 2% caustic soda. 1st UK Nat. Conf. Heat Transfer, I.Mech.E./I.Chem.E., 1, 465 - 472. 

Selection of cleaning process is governed by the soil or contaminant to be removed, the degree of cleanness required, the type of paint to be applied, and the size, shape, material, and end use of the part. In addition, the speed with which the process runs will affect the cleaning characteristics. Methods of cleaning metal surface can be classified as ... 

There is a variety of applications for fiber-based surfaces with self-cleaning characteristics. This includes outdoor apphcations, such as textile roofs for airports and railways, sunscreen textiles, outdoor clothing, but also indoor applications, which come into contact with water or water-based solutions (Fig. 15.10). ... 

Chemical reactions of aimnonia with the silicon surface have also been clearly observed using STS [21], where the disappearance of the it and it states characteristic of the clean surface coincides with the fomiation of Si-H antibonding states corresponding to the dissociation of the ammonia on the Si surface. 

Figure Bl.25.2 shows the XPS spectra of two organoplatinum complexes which contain different amounts of chlorine. The spectrum shows the peaks of all elements expected from the compounds, the Pt 4f and 4d doublets (the 4f doublet is iimesolved due to the low energy resolution employed for broad energy range scans). Cl 2p and Cl 2s, N Is and C Is. Flowever, the C Is caimot be taken as characteristic for the complex only. All surfaces that have not been cleaned by sputtermg or oxidation in the XPS spectrometer contain carbon. The reason is that adsorbed hydrocarbons from the atmosphere give the optimum lowering of the surface free energy and hence, all surfaces are covered by hydrocarbon fragments [9].

Blends of PET and HDPE have been suggested to exploit the availabiUty of these clean recycled polymers. The blends could combine the inherent chemical resistance of HDPE with the processiag characteristics of PET. Siace the two polymers are mutually immiscible, about 5% compatihilizer must be added to the molten mixture (41). The properties of polymer blends containing 80—90% PET/20—10% HDPE have been reported (42). Use of 5—15% compatbiLizer produces polymers more suitable for extmsion blow mol ding than pure PET. 

A.m blent Environment. The environment around the flow conduit must be considered in meter selection. Such factors as the ambient temperature and humidity, the pipe shock and vibration levels, the avadabiHty of electric power, and the corrosive and explosive characteristics of the environment may all influence flow meter selection. Special factors such as possible accidental flooding, the need for hosedown or steam cleaning, and the possibiHty of lightning or power transients may also need to be evaluated. 

Electromagnetic flow meters ate avadable with various liner and electrode materials. Liner and electrode selection is governed by the corrosion characteristics of the Hquid. Eor corrosive chemicals, fluoropolymer or ceramic liners and noble metal electrodes are commonly used polyurethane or mbber and stainless steel electrodes are often used for abrasive slurries. Some fluids tend to form an insulating coating on the electrodes introducing errors or loss of signal. To overcome this problem, specially shaped electrodes are avadable that extend into the flow stream and tend to self-clean. In another approach, the electrodes are periodically vibrated at ultrasonic frequencies. 

Natural gas is attractive as a fuel ia many appHcatioas because of its relatively clean burning characteristics and low air pollution (qv) potential compared to other fossil fuels. Combustion of natural gas iavolves mixing with air or oxygen and igniting the mixture. The overall combustion process does not iavolve particulate combustion or the vaporization of Hquid droplets. With proper burner design and operation, the combustion of natural gas is essentially complete. No unbumed hydrocarbon or carbon monoxide is present ia the products of combustioa. 

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