Increasing costs

As the name implies the company basically rents the rig and crew on a per day basis. Usually the oil company also manages the drilling operation and has full control over the drilling process. This type of contract actually encourages the contractor to spend as much time as acceptable on location . With increased cost consciousness, day rate contracts have become less favoured by most oil companies. 

In the original planning of this book we were at pains to ensure that the preparations in particular were designed to afford a minimum expenditure of time, materials and heating. We hope that the economy thus introduced will be especially appreciated in view of the recent heavily increased cost of chemicals, fuel and laboratory service. This increased cost, incidentally, must necessarily increase the attraction of the small-scale preparations referred to above. 

For some kinds of analyses, it is convenient to have two combined mass spectrometers. This combination naturally increases costs therefore purchase of such hybrid instruments tends to require much... 

The Courtaulds Tencel Process. The increasing costs of reducing the environmental impact of the viscose process coupled with the increasing likelihood that the newer cellulose solvents would be capable of yielding a commercially viable fiber process led Courtaulds Research to embark on a systematic search for a new fiber process in the late 1970s. 

Poly(vinyl chloride). To be converted into film, poly(viayl chloride) [9002-86-22] (PVC) must be modified with heat stabilizers and plasticizers, which increase costs. Plasticized PVC film is highly transparent and soft, with a very high gas-permeation rate. Water-vapor transmission rate is relatively low. At present, PVC film is produced by blown-film extmsion, although casting and calendering are employed for heavier gauges (see Vinyl POLYAffiRS). 

Acryhc and methacryhc nonaqueous dispersions (NADs) are primarily utilized by the coatings industry to avoid certain difficulties associated with aqueous dispersion (emulsion) polymers. Water as a suspension medium has numerous practical advantages, but also some inherent difficulties a high heat of evaporation, a low boiling point, and an evaporation rate that depends on the prevailing humidity. Nonaqueous dispersions alleviate these problems, but introduce others such as flammabihty, increased cost, odor, and toxicity. 

Internal Plasticizers. There has been much dedicated work on the possibiUty of internally plasticized PVC. However, in achieving this by copolymerization significant problems exist (/) the affinity of the growing polymer chain for vinyl chloride rather than a comonomer implies that the incorporation of a comonomer into the chain requites significant pressure (2) since the use of recovered monomer in PVC production is standard practice, contamination of vinyl chloride with comonomer in this respect creates additional problems and (J) the increasing complexity of the reaction can lead to longer reaction times and hence increased costs. Thus, since standard external plasticizers are relatively cheap they are normally preferred. 

Aluminum prices have historically been more stable than other nonferrous metals. Beginning iu the 1970s, however, aluminum prices have fluctuated as shown iu Table 13 (30). These fluctuations reflect increased energy costs as well as increased costs of raw materials. Improvements in production processes as well as a rebalancing of demand and supply are expected to stabilize aluminum prices in the future. 

Secondary Fiber. Increasing costs of taw fiber, legislative mandates for recycling (qv), and avadabdity of inexpensive waste papers have contfibuted to the increased use of recycled fibers. The use of secondary fiber in the United States has grown from 22% of pulp from all sources in 1978 to close to 31% (24 x 10 metric tons) in 1993 (3). Recycled fibers ate sometimes used in special writing papers, but the principal use is for the manufacture of linetboatd, newsprint, tissue, cereal boxes, towels, and molded paper products such as paper plates and egg cartons (see Packaging materials, containers AND INDUSTRIAL materials). 

Computer simulation of the reactor kinetic hydrodynamic and transport characteristics reduces dependence on phenomenological representations and idealized models and provides visual representations of reactor performance. Modem quantitative representations of laminar and turbulent flows are combined with finite difference algorithms and other advanced mathematical methods to solve coupled nonlinear differential equations. The speed and reduced cost of computation, and the increased cost of laboratory experimentation, make the former increasingly usehil. 

Until the 1960s, reclaimed mbber was an important raw material in molded and extmded mbber products, eg, tires, mbber mats, and hard mbber battery cases. With the advent of vinyl, other plastics, and less expensive oil-extended synthetic polymers, reclaimed mbber sales stabilized and decreased. In 1973, the oil embargo and rising energy costs increased costs of the energy-intensive mbber reclaiming process to the point where they matched virgin polymer costs. Increased radial tire production required crack resistance that could not be provided by reclaimed mbber compounds (46). 

Other Resins. Some resins that were important in earlier years have decreased in commercial significance because of scarcity and increased cost of collection. They are Hsted for the historical record. 

Concern over contaminants entering the food chain through fertilizer removed the first option. Increased cost and regulation has all but removed the second. Thus concentration, or recycling, has become more attractive and ia many cases even a necessity. 

Vehicle tests are considered the ultimate in friction material evaluation, but to be accurate these tests must be carefully designed to eliminate variations caused by changing conditions. ControUed-temperature tests and parallel-test controlled vehicles normally perform the function satisfactorily but at increased cost. 

Standards for Gleaned Steel Surfaces. The most important standards (4) used to specify and evaluate cleaned steel surfaces are summari2ed in Table 2 in order of increasing cost. Photographic standards consistent with the written standards in Table 2 are also available (5). 

Vinyl ester resins generally offer mechanical properties superior to those of polyester matrices but at an increased cost. Vinyl esters are chemically similar to epoxy resins but are manufactured via a cold-curing process similar to that used in the manufacture of polyester resins. Vinyl esters offer superior resistance to water and chemical attack and are used in such appHcations as underground pipes, tank liners, and storage tanks (see Vinyl polymers). 

There are two general temperature poHcies increasing the temperature over time to compensate for loss of catalyst activity, or operating at the maximum allowable temperature. These temperature approaches tend to maximize destmction, yet may also lead to loss of product selectivity. Selectivity typically decreases with increasing temperature faster deactivation and increased costs for reactor materials, fabrication, and temperature controls. 

Plug Cocks These valves (Fig. 10-152) are limited to temperatures below 260°C (500°F) since differential expansion between the plug and the body results in seizure. The size and shape of the port divide these valves into different types. In order of increasing cost they are short venturi, reduced rectangular port long venturi, reduced rec taugular port full rectangular port and full round port. 

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