Field testing

The pupil size should be documented at each testing session since pupillary conshiction can reduce retinal sensitivity and mimic progressive visual field loss. 

Several disorders may mimic glaucomatous ONH and/or visual field changes. Those that resemble structural glaucomatous optic neuropathy or interfere wdth assessment of glaucomatous cupping include optic disc anomalies, tilted discs, optic nerve drusen, optic nerve pits, optic nerve colobomas, myelinated nerve fibers, ischemic optic neuropathy and optic atrophy. 

Factors that mimic glaucomatous visual field loss include branch retinal artery occlusion chorioretinal scars retinal areas treated by photocoagulafion or cryotherapy demyelin-afing disorders cerebrovascular accidents, tumors, or other lesions affecting the optic nerve, chiasm, optic tract, optic radiation, ancPor the remaining course of nerve fibers to the occipital cortex. Other abnormalities that could account for pseudo-glaucomatous visual field defects or vision loss include vitreous hemorrhage, proliferative retinopathy or other retinal disorders. 

As discussed in Sect. 30.2.3.4, variation in CCT from normal values may affect lOP measurements by yielding falsely high values w hen CCT is high. 

Animal models for glaucoma have been used to study the pathophysiological basis of glaucoma. Animal based experiments are more representative than cell culture models particularly in the study of aqueous humor dynamics, the trabecular meshw ork-ciliary muscle complex, retinal ganglion cells, ONH axons, ONH framew ork and vascular flow dynamics in glaucoma subtypes (Weinreb and Lindsey, 2005). 

Condncting smdies in animal models often are challenging and occasionally reqnire anesthesia, which might affect the parameter being assessed. Conditioned reflex training may help elicit cooperation. Use of remote controlled implants and newer drug delivery options represent advances made on this front. 

Design of an air sparging system requires a balanced airflow to maintain effectiveness and control of the migration of fluids and vapors. Because of the potential for loss of control, an air sparge system should not be designed or installed without a field pilot test. Design data from pilot tests include  

Site and Pilot Test Data Required for Air Sparging System Design 

Vertical extent of contamination Lithologic barriers Horizontal extent of contamination Volatility of contaminant Radius of sparge influence Optimal flow rates Vent/pressure balance Vapor levels 

Sparging depth Feasibility/sparging depth Number of sparging wells Vapor control (venting) 

Well spacing/flow requirements Compressor size Blower size/well placement Vapor treatment 

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For each field test, a procedure for the AE monitoring is established. 

An important and expensive problem in surface science occurs in the prevention of the attachment of marine animals such as barnacles to ship surfaces, a process known as biofouling. Baier and Meyer [159] have shown that the Zisman plot can be used to predict biofouling, thus avoiding costly field tests to find a successful coating to prevent biofouling. 

Concern for personnel exposure to hydrazine has led to several innovations in packaging to minimize direct contact with hydrazine, eg, Olin s E-Z dmm systems. Carbohydrazide was introduced into this market for the same reason it is a soHd derivative of hydrazine, considered safer to handle because of its low vapor pressure. It hydrolyzes to release free hydrazine at elevated temperatures in the boiler. It is, however, fairly expensive and contributes to dissolved soHds (carbonates) in the water (193). In field tests, catalyzed hydrazine outperformed both hydrazine and carbohydrazide when the feedwater oxygen and iron levels were critical (194). A pubUshed comparison is available (195) of these and other proposed oxygen scavengers, eg, diethyUiydroxylarnine, ydroquinone, methyethylketoxime, and isoascorbic acid. 

Alcohol ethoxysulfates have been used in field tests as nitrogen (177) and carbon dioxide (178) foaming agents. Field use of alcohol ethoxysulfates is restricted to low temperature formations owing to its limited hydrolytic stabihty at low pH and elevated temperature (179). It has been reported that some foams can reduce residual oil saturation, not by oil displacement, but by emulsification and imbibition of the oil into the foam (180). 

Including a surfactant in the caustic formulation (surfactant-enhanced alkaline flooding) can increase optimal salinity of a saline alkaline formulation. This can reduce iaterfacial tension and increase oil recovery (255,257,258). Encouraging field test results have been reported (259). Both nonionic and anionic surfactants have been evaluated in this appHcation (260,261). 

Prevention of Soil Crusting. Acid-based fertilizers such as Unocal s N/Furic (a mixture of urea with sulfuric acid), acidic polymers such as FMC s Spersal (a poly(maleic acid) derivative originally developed to treat boiler scale) (58), the anionic polyacrylamides described previously, as weU as lower molecular weight analogues such as Cytec s Aerotil L Soil Conditioner, have all been used successfully in at least some circumstances to prevent the formation of soil cmsts. It is difficult to prove benefits in the laboratory, and field tests may give variable results depending on local weather conditions. 

Micellar/polymer (MP) chemical enhanced oil recovery systems have demonstrated the greatest potential of all of the recovery systems under study (170) and equivalent oil recovery for mahogany and first-intent petroleum sulfonates has been shown (171). Many somewhat different sulfonate, ie, slug, formulations, slug sizes (pore volumes), and recovery design systems were employed. Most of these field tests were deemed technically successful, but uneconomical based on prevailing oil market prices (172,173). 

A. L. Almerini and S. J. Bartosh, "Simulated Field Tests on Zinc—Air Batteries," Proceedings of the 26th Power Sources Symposium, Adantic City, N.J.,... 

Acrylamide—polymer/Ct(III)catboxylate gel technology has been developed and field tested in Wyoming s Big Horn Basin (211,212). These gels economically enhance oil recovery from wells that suffer fracture conformance problems. The Cr(III) gel technology was successful in both sandstone and carbonate formations, and was insensitive to H2S, high saline, and hard waters (212). 

Disinfection tests can be classified according to the test organism, ie, whether the test employs certain species of bacteria, fungi, or vimses classified as to whether it is a static test or a cidal test, as in a bactericidal vs bacteriostatic test or sporicidal vs sporistatic test or classified as to whether it is a microbial reduction test or an end-point test where all the organisms in the test are apparently killed. Procedures may be distinguished by in vitro or in vivo testing. Another way to consider tests is whether they are screening tests, practical type laboratory tests, or field tests. 

Field Testing. Field tests caimot be readily standardized because the fields of use are different from each other, as are the sources of... 

In field testing, there are many commercial products and instmments available that ate helphil in rapidly detecting, identifying, and quantifying micro organisms. 

Currently, over 110,000 t/yr of engineering resin blends are consumed worldwide, primarily in the transportation, business-machine, hardware, electrical, and appHance industries. Annual growth is projected to be ca 17%/yr. New blends based on PC, terephthalate, and nylon resins are experiencing the greatest expansion (122). These projections could be surpassed if large-volume metal appHcations such as automotive panels are replaced by engineering resin blends which are currently being field-tested. 

During the 1980s, several adaptive controllers were field-tested and commerciahzed in the U.S. and abroad, including products by ASEA (Sweden), Leeds and Northrup, Foxboro, and Sattcontrol. At the present time, some form of adaptive tuning is available on almost all PID controllers. The ASEA adaptive controller, Novatune, was... 

The subject of adaptive control is one of current interest. New algorithms are presently under development, but these need to be field-tested before industrial acceptance can be expected. It is clear, however, that digital computers will be required for implementation of self-adaptive controllers due to their complexity. An adaptive controller is inherently nonlinear and therefore more complicated than the conventional PID controller. 

Because many of the techniques, especially those associated with the recovery of materials and energy and the processing of solid hazardous wastes, are in a state of flux with respect to application and design criteria, the objective here is only to introduce them to the reader. If these techniques are to be considered in the development of waste-management systems, current engineering design and performance data must be obtained from consultants, operating records, field tests, equipment manufacturers, and available literature. 

Many computer codes, both public and private, are available to model dense cloud dispersion. A detailed review of these codes, and how they perform relative to actual field test data, is available (Hanna, Chang, and Strimaitis, Atmospheric Environment, vol. 27A, no. 15, 1993, pp. 2265-2285). An interesting result of this review is that a simple nomograph method developed by Britter and McQuaid (1988) matches the available data as well as any of the computer codes. This method will be presented here. 

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