Softness scales

It may be desirable to first clean the pipeline with a polyurethane foam swab. This material can be purchased commercially either in specific cut sizes, or in bulk, which can be cut to the desired size. Swabs will effectively remove soft scales and loose material. Their method of use is identical to that of the pig. 

Mixing of unlike brines can cause the precipitation of sulfates of barium, strontium, and calcium. This hard scale, which is a nuisance in oilfield flow lines, often can be explained by leaky casing. Soft scale, composed of calcium carbonate, usually is caused by the loss of dissolved carbon dioxide from the brine during pressure reduction. 

A solvent softness scale, dependent on the thermodynamics of transfer of ions from water to the target solvent, has been proposed (Marcus 1987). Since soft ions prefer soft solvents and hard ions hard solvents, and since silver ions are soft, whereas sodium and potassium ions are hard, the difference ... 

Another measure of solvent softness proposed is based on Raman spectroscopic measurements. It is the wavenumber shift Av of the Raman band for the symmetrical stretching of Br-Hg-Br in the solvent relative to that of gaseous mercury bromide (Persson 1986). A solvent softness scale, called Ds = [A (Hg-Br)/cm-J] has accordingly been established. An extension of this scale to further solvents is difficult in those cases where the solubility of mercury bromide is insufficient for the ca. 0.2 mol dm-3 required for the Raman spectral measurements. 

Iodoacetylenes as well as iodine cyanide are soft Lewis acids (Laurence etal. 1981), which interact with basic solvents yielding characteristic wavenumber shifts Av (C-I) (e g., for ICN relative to the wavenumber in CCI4 solutions). These shifts differ for soft solvents, with sulfur or selenium donor atoms or n systems, and hard solvents, with oxygen or nitrogen donor atoms. However, these authors have not converted this observation and their data to a solvent softness scale. In fact, if prorated values of A v (O-H), for phenol, relative to CCI4 solutions, see B0 H above, representing the hard basicity of the solvents, are subtracted, the remainder measures the solvent softness. Quantitatively,... 

In the rest of the paper, we list the individual contributions. Sections 3 and 4 are devoted to the soft scale and hard scale ones, respectively. The final result of this paper is presented in the last Section. Notations used throughout the paper are collected in Appendix. In order to make the formulae more transparent, we write the nonsingular soft scale operators with coefficients taken at d = 3. 

As usual, Bp receives contributions from both hard and soft scales and for this reason we write it as Bp = B oft + Bpard. We then obtain [4] ... 

The values of orbital energy, while Klopman has it the other way round. The present procedure has been adopted primarily in order to facilitate a comparison between the softness scales obtained by the Klopman parameter and by the new parameter softness parameter should rather increase with the softness. 

A wasp, parasite of soft scales used in orchards and in protected crops... 

The near-random redistribution of fluorine and chlorine in oxygen-donor boron trihalide adducts (27, 29) might be rationalized using this principle since oxygen is between fluorine and chlorine on the hard-soft scale (140), and there is less discontinuity of ligands in terms of hard-soft properties. However, amine adducts of BHF2 do tend to disproportionate to give the BF3 and BH3 adducts (130). 

A detailed discussion and comparison of all these and further solvent softness scales can be found in references [173, 238, 239]. For other Lewis acid/base parameters of EPD and EPA solvents, derived from calorimetric measurements [e.g. Gutmann s donor and acceptor numbers), see reference [65] and Section 2.2.6. 

Leaves yellow stems and leaves covered with small bumps. Cause Scales. Probably the most serious pests of ash are scale insects, with oystershell scale as the most important, especially in the Midwest. Putnam scale, San Jose scale, and soft scale (in warmer climates) also occur. For control information, see Leaves yellow stems and leaves covered with small bumps on page 237. 

Yellow leaves Citrus and other fruit trees Soft scales, armored scales... 

Beneficiai Effect Adults and larvae of many species feed on aphids and soft-bodied pests some species prefer mealybugs, spider mites, or soft scales. Native lady beetles are important biological controls for aphids in gardens and orchards. In western regions. Stelhonis spp. provide excellent control of... 

Lady beeties Hippodamia convergens Aphids, mealybugs, soft scales, spider mites. Not recommended for outdoor release use in greenhouses at a rate of 3-5 beetles per plant or 500 per home greenhouse. Unreliable autdoors due to migration, unless released over community-wide area other species good candidates for outdoor releases. 

Scale predatory beetles Chilocorus nigrltus, Lindorus lophanthae Soft scales, especially soft brown scale. Minimum order of several hundred sufficient for a greenhouse confine 10-20 beetles for a month to an infested houseplant. Reliable, especially indoors. 

Brown scale, citrus and, 73 Brown soft scale, 321 Brown spot, celery and, 64 Brown stink bugs. 327... 

Evans HC, Hywel-Jones NL. Entomopathogenic fungi. In Ben-Dev Y, In Hodgson CJ, eds. Soft Scale Insects Their Biology, Natural Enemies and Control. Vol. 7B. Amsterdam, The Netherlands Elsevier, pp 3-27. 

The use of a device in the hard water circuit prior to a plate heat exchanger resulted in the deposition of a soft scale easily removed by brushing, in contrast to the hard scale formed in the absence of the magnetic unit. 

Zacchi, L., Vaughan-Martini, A. (2003). Distribution of three yeast and yeastlike species within a population of soft scale insects Saissetia oleae) as a function of developmental age. Annals of Microbiology 53,43-46. 

Although an exact softness scale is neither available nor advisable, empirical systematization of various acids and bases is essential for correlating experimental observations. The best compromise would be to establish guidelines for the rough estimation of softness in a comparative sense. 

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