This article traces the use of pearls from antiquity to the initial appearance of cultured pearls in the 1920s. The first section touches on the early fascination with pearls as revealed througll historical literature, including Cleopatra's pearls, Roman pearl jewelry, and medicinal pearl recipes o j t h e Middle Ages. During the ~e n a i s s~n c~, Spain's exploration of the N e w Worldresulted in the discovery of vast quantitiesof valuable pearls that were eventually spread throughout Europe. Queen Elizabeth 1's magnificent collection of pearls and the intriguing baroque pearl figurines of the later Renaissance are also discussed. T h e article concludes w i t h a review of pearl fashion from 1800 to 1930, including delicate Victorian seed-pearl jewelry, Queen Alexandra's dog-collar chokers, and Art Deco pearl-inlaid jewelry.

By S a l l y A. Thomas a n d Hing W a Lee The Chinese have labored to perfect the art of gemstone carving for several thousand years. Beginning with primitive tools and limited materials, they eventually developed the iron-tipped spindles and treadle machines that were to become the traditional tools of the trade for two millenia. With these relatively simple implements andmeticulous craftsmanship, Chinese master carvers have produced some of the world's most sophisticated gemstone carvings. Within the past 10 years, however, increased government01 participation, the ovailability of powerdriven machinery, and more varied carving materials have had a major impact on gemstone carving in China.

Steamflood-produced waters commonly contain suspended solids, oil, hardness-causing minerals, sulfide, and silica. Removal of these contaminants would make many of these waters suitable for recycling as steamer feedwater. Reuse. of steamflood-produced waters increases steamer feedwater supplies and reduces water disposal requirements. This paper describes a field pilot study of silica removal from steamflood-produced water in the south Texas tar sands region. A hot-lime precipitation process was used to reduce dissolved silica (Si0 2 ) concentrations from 400 to less than 50 mg/L Si0 2 in Mary R. Saner Ranch produced water. Most water systems using hotlime precipitation for silica removal-require the addition of magnesium salt, as well as lime, to enhance silica removal. In this field study, however, addition of magnesium salt did not improve silica removal efficiency. Hydrated lime, Ca(OHh, alone was sufficient to attain desired silica residual, 50 mg/L Si0 2 . The dissolved silica adsorbed onto the CaC0 3 crystals formed by lime reacting with the alkalinity present in the produced water. Required lime dosage was approximately 900 mg/L Ca(OHh.Residual silica concentration was found to be strongly related to both precipitator ,effluent pH and calcium ion concentration. Therefore, on-line pH and hardness monitoring may be used to estimate and to control residual silica concentration. A 50,000-B/D [7950-m 3 Id] produced-water treating plant has been designed from the results of this pilot study.

Previous studies of the information integration rules used in area judgements have employed either rating scales, or area-matching techniques in which a pair of rectangles is presented and one is adjusted to match the other in size. In this study a PEST (Parameter Estimation by Sequential Testing) procedure was used to track the point of subjective equality between a standard rectangle and a comparator rectangle of different shape. This method has the advantage that a simple binary choice is the only response required. Functional measurement analysis was carried out on groups of adults, 5and 10-year-old children who each completed two replications of a 3 x 3 design in which 3 values of standard area were combined with 3 values of comparator width. The results supported previous findings that young children generally use an addition (height + width) rule whereas older children and adults use a multiplying rule in area judgement. A second experiment confirmed the difference in predominant strategy between 5and 11-year-old children and eliminated one possible artefact due to the starting value of the tracking series. This confirmation of the development change in area-judgement strategies using a different method suggests that the strategy changes are real and not an artefact of measurement techniques. In addition, the present technique reveals more widespread use of the multiplying strategy than previous methods based on rating scales. The implications of this finding are discussed.

Pigging has been employed over the decades to provide liquid, solid and depositmanagement in pipelines. Pigging of subsea tie-backs to manage liquid holdupand deposits is a significant flow assurance challenge. Deepwater developmentscontinue to increase this challenge, with longer flowlines, longer risers andgreater potential for solids deposition. Significant production risks include aseparator trip caused by a surge in liquids/solids into topsides equipment, andthe potential for lost production due to a stuck pig in the offshore flowline. By-pass pigging has been widely used to reduce the pigging risks in longflowlines by spreading the collected liquid and/or scraped deposits in front ofthe pig. By-pass pigging is a complex fluid dynamics operation. Only limitedsuccess in predicting slug size and duration has been reported for by-passpigging operations, even with sophisticated modeling tools. This paper presentsinformation about by-pass pigging experience for a wet gas/condensate subseaflowline (ID = 20.6" and L = ~10 km) running from a wellhead platform to acentral processing platform. The operational experience includes optimizationof the by-pass opening in the pig, separator liquid drain rate control, andseparator level control. Solids recovery will be discussed. Field data fromby-pass pigging operations will be compared to predictions from two models. Based on the field data, updated recommendations for modeling by-pass piggingoperations will be discussed. Introduction Pigging has been used for many decades to perform various tasks such aspipeline inspection and cleaning. Numerous pipeline systems rely on pigging asa major flow assurance control for hydraulics (liquid inventory management), corrosion management (under deposit corrosion and/or top of line corrosion), and solid management such as wax, asphaltene, sand and scale control. Asoil/gas production continues to move to deep sea areas, pigging of long subseatie-backs to manage liquid holdup and terrain slugging/liquid surge due to longrisers is a significant flow assurance challenge. Production risks include aseparator trip caused by a surge in liquids/solids into topsides equipment, andthe potential for lost production due to a stuck pig in the offshoreflowline. In order to minimize the liquid/solid surge risks in long flowlines/pipelines, by-pass pigging has been used in various offshore flowlines. Properly designedby-pass pigging can effectively minimize the liquid/solid surge by spreadingthe collected liquid and/or scraped deposits in front of the pig, as shown inFigure 1. The gas bypassing the pig elongates the liquid slug in front of thepig by creating a certain void fraction in the slug. Several pigging models are widely used to predict liquid surge risk. It isimportant to validate the by-pass pigging models with field data to haveconfidence in surge capacity design; however, very few attempts have beenreported. Wu et al (1996) reported the size and duration of the liquid surgeobserved during a field test of by-pass pigging operations was about 30% of thepredicted surge volume. This paper presents liquid surge data collected during by-pass piggingoperations for a wet gas/condensate subsea flowline (ID = 20.6" and L = ~10 km)running from a wellhead platform to a central processing platform in anIndonesian offshore field. Field data from by-pass pigging operations arecompared to predictions from the OLGA model and to a model proposed by Fan andDanielson (2009). This field data and model prediction results are valuable todevelop liquid surge prediction practices for wet gas/condensate flowlines. These results will help pipeline design engineers to accurately estimate therequired surge capacity and will assist production staff to optimize pipelinepigging operations.