Wyllie equation


Having been cleaned, the mud is transferred into mud tanks, large treatment and storage units. From there a powerful pump brings the mud up through a pipe stand pipe) and through a hose connected to the swivel (rotary hose) forcing it down the hole inside the drill string. Eventually the cleaned mud will exit again through the bit nozzles.  [c.39]

Drilling equipment and drilling activities have to be carried out in complex and often hostile environments. Surface and subsurface conditions may force the drilling rig and crew to operate close to their limits. Sometimes non-routine or unexpected operating conditions will exceed the rating of equipment and normal drilling practices may not be adequate for a given situation. Thus, drilling problems can and do occur.  [c.56]

The drop shape analysis technique can also be applied to images taken from above sessile drops to determine contact angles [108]. In one approach, the diameter of the drop in contact with the surface is measured from above and the contact angle is determined from integration of the Laplace equation (II-7) given the surface tension and drop volume. This approach is applicable only to systems where the contact angle is less than 90° since the observed diameter will exceed the contact diameter when 6 > 90°. For these nonwetting cases, the maximum equatorial diameter can be measured to determine contact angle [109]. The contact angle can also be calculated from interferometric measurement of the meniscus profile of a horizontal film in a capillary [110].  [c.363]

A nontrivial solution will exist only if  [c.102]

From Table 2.26b the area under the normal curve from — 1.5cr to -I- 1.5cr is 0.866, meaning that 86.6% of the measurements will fall within the range 30.00 0.45 and 13.4% will lie outside this range. Half of these measurements, 6.7%, will be less than 29.55 and a similar percentage will exceed 30.45. In actuality the uncertainty in z is about 1 in 15 therefore, the value of z could lie between 1.4 and 1.6 the corresponding areas under the curve could lie between 84% and 89%.  [c.194]

The most direct test is to compare the BET area with the geometrical area of the solid. Unfortunately, comparisons of this kind are relatively rare on account of experimental difficulties. The choices are to work with, say, single crystals having a well defined surface, when techniques of quite extraordinary sensitivity will be needed for measurement of the adsorption or, to obtain a larger surface area by use of thin sheets, narrow rods or small spheres, and run the risk that the surface will not be truly smooth so that the actual area will exceed the geometrical area.  [c.62]

Now we are ready to construct the ladder diagram for HE (Figure 6.4). The ladder diagram consists of a vertical scale of pH values oriented so that smaller (more acidic) pH levels are at the bottom and larger (more basic) pH levels are at the top. A horizontal line is drawn at a pH equal to piQ HF- This line, or step, separates the solution into regions where each of the two conjugate forms of HE predominate. By referring to the ladder diagram, we see that at a pH of 2.5 hydrofluoric acid will exist predominately as HE. If we add sufficient base to the solution such that the pH increases to 4.5, the predominate form becomes F .  [c.151]

Space-charge effects cause an ion beam to spread apart. A beam of ions of the same electric charge (all positive or all negative) means that the electric field from one ion can be felt by all its neighbors. The repulsive effect drops relative to their distance apart d), approximately as d. Consequently, a dense beam of ions produces a large effect, while a beam containing few ions per unit volume will be subject to only a feeble effect. Ion guides help to contain ions and to offset the tendency for the beam to spread. In this way, most of a beam of ions traveling from one aperture to another across the ends of an ion guide will exit through the second aperture.  [c.372]

Asahi commercialized their "mark 2" high speed spinning system which operated at 1000 m /min, and ate now working on systems which will exceed 2000 m /min.  [c.351]

Laxation Thresholds. AH sugar alcohols have the potential to cause diarrhea or flatulence owing to their slow absorption from the small intestine. Sorbitol and mannitol have laxation thresholds of 50 and 20 g/d, respectively, and where it is reasonably foreseeable that consumption will exceed these levels, foods must bear the statement "Excess consumption may have a laxation effect", per 21 CFR 184.1835 (Sorbitol) and 180.25 (mannitol). Maltitol, isomalt, lactitol, maltitol solution (symp), and hydrogenated starch hydrolysates (HSH) are reported by manufacturers to have laxation thresholds of 100 g/d, 50 g/d, 20 g/d, 75 g/d, and 75 g/d, respectively. These sugar alcohols are not FDA-regulated as of 1996.  [c.53]

If there is a significant resistance to transport of the reactant in the pores, a concentration gradient will exist at steady state, whereby the concentration of the reactant is a maximum at the particle periphery and a minimum at the particle center. The product concentration will be higher at the particle center than at the periphery. The concentration gradients provide the driving force for the transport.  [c.171]

If the tube diameter is appreciably larger than the quenching distance, S will exceed p in some parts of the flowing mixture due to a lack of quenching, and the flame will then propagate down the tube as far as there is mixture to consume. This undesirable condition is referred to as flashback. If, on the other hand, p exceeds S in the mixture flow, the flame lifts from the port and blows off. This condition is referred to as blowoff and like flashback should be avoided (Fig. 8). The velocity gradient at the wall, is defined as  [c.523]

A detailed statistical picture of the supply and consumption of copper and copper alloys in the United States is available annually (53). The statistics trace the flow of copper from mining and scrap collection through smelting, refining, and ingot making to the wire mills, brass mills, and foundries and then on to the final markets. Table 7 summarizes U.S. uses of copper through 1990. There are strong indications that the future demand for copper will exceed production capacity.  [c.209]

When to Scrap an Existing Process Let us suppose that a company invests 50,000 in a manufacturing process that has positive net annual flows (after tax) Acp of 10,000 in each year. During the third year of operation, an alternative process becomes available. The new process would require an investment of 40,000 but would have positive net annual cash flows (after tax) of 20,000 in each year. The cost of capital is 10 percent, and it is estimated that a market will exist for the product for at least 6 more years. Should the company continue with the existing process (project H), or should it scrap project H and adopt the new process (project 1)  [c.816]

Noise. Two identical fans have a noise level 3 dBa higher than one fan, while eight identical fans have a noise level 9 dBa higher than a single fan. Noise level at the plant site is affected by the exchanger position, the reflective surfaces near the fan, the hardness of these surfaces, and noise from adjacent equipment. The extensive use of aircooled heat exchangers contributes significantly to plant noise level.  [c.1081]

A long heating cycle is necessaiy because the size of the solid objects or permissible heating temperature requires a long holdup for internal diffusion of heat or moisture. This case may apply when the cycle will exceed 12 to 24 h.  [c.1190]

If the liqmd-phase reaction is extremely fast and irreversible, the rate of absorption may in some cases be completely governed by the gas-phase resistance. For practical design purposes one may assume (for example) that this gas-phase mass-transfer limited condition will exist when the ratio yj/y is less than 0.05 everywhere in the apparatus.  [c.1363]

In a gas stream cariying dust or fume, some degree of particle flocculation will exist, so that both discrete particles and clusters of adhering particles will be present. The discrete particles composing the clusters may be only loosely attached to each other, as by van der Waals forces [Lapple, Chem. Eng., 75(11), 149 (1968)]. Flocculation tends to increase with increases in particle concentration and may strongly influence collector performance.  [c.1580]

There are numerous solubility data in the literature the standard reference is by Seidell (loc. cit.). Valuable as they are, they nevertheless must be used with caution because the solubihty of compounds is often influenced by pH and/or the presence of other soluble impurities which usually tend to depress the solubihty of the major constituents. While exact values for any system are frequently best determined by actual composition measurements, the difficulty of reproducing these solubility diagrams should not be underestimated. To obtain data which are readily reproducible, elaborate pains must be taken to be sure the system sampled is at equihbrium, and often this means holding a sample at constant temperature for a period of from 1 to 100 h. While the published cui ves may not be exac t for actual solutions of interest, they generally will be indicative of the shape of the solubility cui ve and will show the presence of hydrates or double salts.  [c.1654]

The hierarchy s categories are prioritized so as to promote the examination of each individual alternative prior to the investigation of subsequent options (i.e., the most preferable alternative should be thoroughly evaluated before consideration is given to a less accepted option). Practices that decrease, avoid, or eliminate the generation of waste are considered source reduction and can include the implementation of procedures as simple and economical as good housekeeping. Recycling is the use, reuse, or reclamation of wastes and/or materi s that may involve the incorporation of waste recovery techniques (e.g., distillation, filtration). Recycling can be performed at the facihty (i.e., on-site) or at an off-site reclamation facility. Treatment involves the destruction or detoxification of wastes into nontoxic or less toxic materials by chemical, biological, or physical methods, or any combination of these control methods. Disposal has been included in the hierarchy because it is recognized that residual wastes will exist the EPA s so-c led ultimate disposal options include land-filhng, land farming, ocean dumping, and deep-well injection. However, the term ultimate disposal is a misnomer, but is included here because of its adaptation by the EPA.  [c.2163]

Pressure affects flash point. A decrease in pressure lowers the flash point. With toluene, for example, at two-thirds of an atmosphere the vapor pressure must be only 0.74 kPa (5.6 mm Hg) to equal the LFL of 1.1 percent. (No significant difference in LFL will exist at two-thirds of an atmosphere compared to the published LFL of 1.1 percent at one atmosphere.) This vapor pressure occurs at —3°C, corresponding to a decrease in flash point of about 7.4°C from one atmosphere. Conversely, an increase in pressure raises the flash point.  [c.2316]

Set the release pressure of a rupture disk or other vent closure as close to the operating pressure as practical. Note that the maximum overpressure in a vented explosion will exceed the opening pressure of the vent closure.  [c.2319]

Now we are ready to construct the ladder diagram for HF (Figure 6.4). The ladder diagram consists of a vertical scale of pH values oriented so that smaller (more acidic) pH levels are at the bottom and larger (more basic) pH levels are at the top. A horizontal line is drawn at a pH equal to pi[c.151]

For a higher ambient temperature, the end temperature of the winding will exceed the permissible limit by the amount the ambient temperature is higher. For example, for a class E motor, an ambient temperature of 30°C will cause the end temperature to reach I25°C as against 115°C permissible by the resistance method. For details refer to Sections 9.1 and I 1.3.2.  [c.15]

Lio= / ated life of bearings at 90% reliability, i.e. 90% of bearings produced by a manufacturer will exceed this life  [c.215]

The above would be true if the motor is assumed to be at a standstill. If the motor had been running at almost full speed, this voltage would assume yet higher proportions, say, up to 5 p.u. due to the motor s own self-induced e.m.f., which may fall phase apart with the system voltage. Such a situation may arise during a fast bus transfer, when a running motor is switched over from one source to another or during a re-acceleration period after a momentary power failure. But since the amplitude and rate of rise of the recovery voltage (r.r.r.v.) at switching ON are influenced by the surge impedance of the closing circuit, which is formed by the surge impedance of the motor and the interconnecting cables, the time of rise, t (Figure 17.6) and the amplitude of the surge voltage, V, would rise with the length of the cable between the switching device and the motor terminals (Section 18.6.2). Such transient voltages will exist on the system just up to the contact making and are thus of extremely short duration (in ps).  [c.568]

Aniline will be used as a second example. It has a pK of 4.60 at 25° in H2O. If it is placed in aqueous solution at pH 1.60 it will exist almost completely (99.9%) as the anilinium cation. This solution can then be extracted with solvents e.g. diethyl ether to remove neutral impurities. The pH of the solution is then adjusted to 7.60 whereby aniline will exist as the free base (99.9%) and can be extracted into diethyl ether in order to give purer aniline.  [c.7]

Consider die following intuitive scheme, in which the timing between a pair of pulses is used to control the identity of products [ ]. The scheme is based on the close correspondence between the centre of a wavepacket in time and that of a classical trajectory (Elirenfest s theorem). The first pulse produces an excited electronic state wavepacket. The time delay between the pulses controls the time that the wavepacket evolves on the excited electronic state. The second pulse stimulates emission. By the Franck-Condon principle, the second step prepares a wavepacket on the ground electronic state with the same position and momentum, instantaneously, as the excited-state wavepacket. By controlling the position and momentum of the wavepacket produced on the ground state through the second step, one can gain some measure of control over product fonnation on the ground state. This pump-dump scheme is illustrated classically in figure Al.6.27. The trajectory originates at the ground-state surface minimum (the equilibrium geometry). At t = 0 it is promoted to the excited-state potential surface (a two-dimensional hamionic oscillator in this model) where it originates at the Condon point, that is, vertically above the ground-state minimum. Since this position is displaced from equilibrium on the excited state, the trajectory begins to evolve, executing a two-dimensional Lissajous motion. After some time delay, the trajectory is brought down vertically to the ground state (keeping both the instantaneous position and momentum it had on the excited state) and allowed to continue to evolve on the ground-state, figure Al.6.27 shows that for one choice of time delay it will exit mto chaimel 1, for a second choice of time delay it will exit into channel 2. Note how the position and momentum of the trajectory on the ground state, innnediately after it comes down from the excited state, are both consistent with the values it had when it left the excited state, and at the same time are ideally suited for exiting out their respective chaimels.  [c.270]

The existence of multiple stable confonnations with different affinities implies time-dependent dissociation a molecule initially associated in a low-affmity confonnation has the chance to switch to a high affinity one before dissociating. Even a single confonnation may actually comprise many slightly different subconfonnations ( confonnational substates , CS, possibly rotamers) separated by finite barriers [7, 40], At some finite temperature the molecule will exist in several different CS (i.e. ergodicity is broken), each of which may be presumed to make a slightly different contribution to the rate of any process in which that confonnation of the biopolymer participates. In biological (and inanimate glassy) systems relaxation is empirically often found to follow stretched exponential (Kohlrausch) decay  [c.2831]

Technetium is a silvery-gray metal that tarnishes slowly in moist air. The common oxidation states of technetium are +7, +5, and +4. Under oxidizing conditions technetium (Vll) will exist as the pertechnetate ion, TcOr-. The chemistry of technetium is said to be similar to that of rhenium. Technetium dissolves in nitric acid, aqua regia, and cone, sulfuric acid, but is not soluble in hydrochloric acid of any strength. The element is a remarkable corrosion inhibitor for steel. The metal is an excellent superconductor at IIK and below.  [c.107]

There will be incidences when the foregoing assumptions for a two-tailed test will not be true. Perhaps some physical situation prevents p from ever being less than the hypothesized value it can only be equal or greater. No results would ever fall below the low end of the confidence interval only the upper end of the distribution is operative. Now random samples will exceed the upper bound only 2.5% of the time, not the 5% specified in two-tail testing. Thus, where the possible values are restricted, what was supposed to be a hypothesis test at the 95% confidence level is actually being performed at a 97.5% confidence level. Stated in another way, 95% of the population data lie within the interval below p + 1.65cr and 5% lie above. Of course, the opposite situation might also occur and only the lower end of the distribution is operative.  [c.201]

Almost any chemical reaction can serve as a titrimetric method provided that three conditions are met. The first condition is that all reactions involving the titrant and analyte must be of known stoichiometry. If this is not the case, then the moles of titrant used in reaching the end point cannot tell us how much analyte is in our sample. Second, the titration reaction must occur rapidly. If we add titrant at a rate that is faster than the reaction s rate, then the end point will exceed the equivalence point by a significant amount. Finally, a suitable method must be available for determining the end point with an acceptable level of accuracy. These are significant limitations and, for this reason, several titration strategies are commonly used.  [c.274]

The form of the response for an adiabatic three-component system (two adsorbable components in an inert carrier) is illustrated in Figure 10. In general, if there are n components (counting both heat and nonadsorbing species as components), the response contains in — 1) transitions or mass transfer 2ones, separated by in — 2) plateaus between the initial and final states. When the change imposed at the column inlet involves an increase in the concentration of the more strongly adsorbed species, the concentration at the intermediate plateau will exceed both its initial concentration and its final steady-state concentration. This phenomenon, known as roU-up, results from displacement by the more strongly adsorbed species, which travels more slowly through the column.  [c.261]

Because HCl is produced as a by-product, supply and demand are out of balance merchant supply is presently almost double merchant demand. Furthermore, this imbalance is expected to increase over the next several years because of the restrictions imposed on CFC production. Although proposed CFC replacements are expected to require chlorinated precursors for their manufacture, only minor amounts of chlorine will be present in the final product, and the balance will exit the reaction as by-product HCl that will require disposal in an already saturated market. Environmental pressures related to HCl disposal are adding to concerns over the increasing supply. Resistance to HCl deep welling is growing and regulation is increasing. Thus HCl may be forced to find new appHcations in the chlorine markets. Although the chlor—alkali industry has reacted to environmental concerns by neiitra1i2ing many HCl waste streams before disposal, finding appropriate uses for by-product HCl without impacting chlorine production is a challenge facing the industry in the future.  [c.517]

Worldwide, approximately 85% of acetone is produced as a coproduct with phenol. The remaining 17% is produced by on-purpose acetone processes such as the hydration of propylene to 2-propanol and the dehydrogenation of 2-propanol to acetone. The cost of production of 2-propanol sets the floor price of acetone as long as the acetone demand exceeds the coproduct acetone supply. However, there is a disparity in the growth rates of phenol and acetone, with phenol demand projected at 3.0%/yr and acetone demand at 2.0%/yr. If this continues, the coproduct supply of acetone will exceed the total acetone demand and on-purpose production of acetone will be forced to shut down the price of acetone is expected to fall below the floor price set by the on-purpose cost production. Projections indicate that such a situation might occur in the world market by 2010. To forestall such a situation, companies such as Mitsui Petrochemical and Shinnippon (Nippon Steel) have built plants without the coproduction of acetone.  [c.290]

Oral contraceptives are among the most popular form of reversible contraception in most countries. As of the early 1990s, over 60 million women around the world use the pill and almost 150 million women have used oral contraceptives sometime during their reproductive fives (7). The commercial market for oral contraceptives is large and expanding. U.S. dmg store purchases alone will exceed 1 biUion in 1992.  [c.111]

As safety begins with the process design, an inherently safe process is the objective of modern plant designs. When this cannot be achieved, process hazards of varying severity will exist. Where these hazards put plant workers and/or the general public at risk, some form of protective system is required. Process safety management addresses the various issues, ranging from assessment of the process hazard to assuring the integrity of the protec tive eqiiipment installed to cope with the hazard. en the protective system is an automatic action, it is incorporated into the safety interlock system, not within the process controls.  [c.796]

Batch Furnaces, Other Furnace Types, and Kilns Batch furnaces are employed mainly for the heat treating of metals, such as anneahng, normalizing, and drawing (tempering), and for the diying and calcination of ceramic articles. Many speciahzed furnaces have been designed for these purposes and may be either batch or continuous in operation. Batch furnaces are used in chemical processing for the same purposes as batch tray and truck dryers, when the diying or process temperature exceeds that which can be tolerated by unlined metal walls ordinary tray and truck diyers are rarely employed when the circulating-gas temperature will exceed 600 to 700 K. They are employed for smaU-batch calcination, thermal decompositions, and other chemical reactions these are the same as those reactions performed on a larger scale in rotaiy kilns, hearth furnaces, and shaft furnaces.  [c.1193]

The rotating annular bed system for liquid chromatographic separation (two-dimensional chromatography) is analogous to the horizontal adsorbent wheel for gases. Feed to be separated flows to a portion of the top face of an annular bed of sorbent. A displacement purge in the form of a solvent or carrier gas flows to the rest of the annulus. The less strongly adsorbed components travel downward through the sorbent at a higher rate. Thus, they will exit at the bottom of the annulus at a smaller angular distance from the feed sector. The more strongly adsorbed species will exit at a greater angle. The mechanical and packing complexities of such an apparatus have been overcome for a pressurized system by workers at the Oak Ridge National Laboratory shown in Fig. 16-56 [Canon, Begovich, and Sisson, Sep. Sci. TechnoL, 15, 655-678 (1980)]. Several potential applications are reviewed by Carta and Byers [Chromatographic ana Membrane Processes in Biotechnology, NATO ASI Proceeding, Kluwer, 1991].  [c.1554]

Thickener-Basin Area The area requirements for thickeners frequently are based on the sohds flux rates measured in the zonesettling regime. Theoiy holds that, for any specific sedimentation condition, a critical concentration which will limit the solids throughput rate will exist in the thickener. This critical concentration will be evidenced as a pulp bed of variable depth in which the sohds concentration is fairly uniform from top to bottom. Since the underflow concentration usually will be higher than this, graduahy increasing concentrations will be found with progressing depth in the region beneath this constant-concentration zone. As the concentration within this critical zone represents a steady-state condition, its vertical extent may vaiy continually, responding to minor changes in the feed rate, underflow withdraw rate, or flocculant dosage. In thickeners operating at relatively high underflow concentrations, with long  [c.1679]

It seems needless to state but is frequently overlooked that test results are vahd only to the extent that the slurry and the test conditions duphcate what will exist in the operating plant. This may involve testing on a small scale (or even on a large one) with a shpstream from an existing unit, but the dependabihty of the data is often worth the extra effort involved. Most centrifuge manufac turers provide testing services and demonstration facihties in their own plants and maintain a supply of equipment for field-testing in the customer s plant, such as with a pilot centrifuge mounted on a mobile truck or trailer.  [c.1741]

Almost any chemical reaction can serve as a titrimetric method provided that three conditions are met. The first condition is that all reactions involving the titrant and analyte must be of known stoichiometry. If this is not the case, then the moles of titrant used in reaching the end point cannot tell us how much analyte is in our sample. Second, the titration reaction must occur rapidly. If we add titrant at a rate that is faster than the reaction s rate, then the end point will exceed the equivalence point by a significant amount. Finally, a suitable method must be available for determining the end point with an acceptable level of accuracy. These are significant limitations and, for this reason, several titration strategies are commonly used.  [c.274]

Early aluminum reduction plants were responsible for air pollution because of the fluoride emissions from their operations. Fluoride emissions can cause severe damage to vegetation and to animals feeding on such vegetahon. The end result was an area surrounding the plant devoid of vegetation. Such scenes are reminiscent of those downwind from some of the uncontrolled copper smelters. New aluminum reduction plants are going to considerable expense to control fluoride emissions. Some of the older plants are finding that the cost of control will exceed the original capital investment in the entire facility. Where the problem is serious, control agencies have developed extensive sampling networks to monitor emissions from the plant of concern.  [c.88]


See pages that mention the term Wyllie equation : [c.240]    [c.58]    [c.36]    [c.657]    [c.58]    [c.564]    [c.706]    [c.879]   
Standard Handbook of Petroleum and Natural Gas Engineering Volume 1 (1996) -- [ c.1052 ]