Double Bottom Structure
An inner bottom or tank top may be provided at a minimum height above the bottom shell, and maintained watertight to the bilges. This provides a considerable margin of safety, since in the event of bottom shell damage only the double bottom space may be flooded. The space is not wasted but utilized to carry oil fuel and fresh water required for the ship, as well as providing ballast capacity.
Balance Piston
U is desirable to have additional axial-load control on the multistage compressor. A balance piston, also referred to as the balance drum, can be located at the discharge end. The balance piston consists of a rotating element that has a specified diameter and an extended rim for sealing. The area adjacent to the balance piston opposite the last stage location is vented, normally to suction pressure.
Batch and Continuous Extraction Modes
One means of classifying extractions is based on the mode of operation, batch or continuous and static or dynamic. The terms batch and continuous refer to how the sample feed is placed into the system. In batch extraction processes the entire material to be extracted is loaded into the extraction device. In the case of continuous extractions the feed is continuously introduced into the extraction device. Static and dynamic describe the exposure of the two phases.
Checking crownwheel and pinion tooth contact
Prepare crownwheel for examining tooth contact marks Fig. 7.8 After setting the correct backlash, the crownwheel and pinion tooth alignment should be checked for optimum contact. This may be achieved by applying a marking cream such as Prussian blue, red lead, chrome yellow, red or yellow ochre etc. to three evenly spaced groups of about six teeth round the crownwheel on both drive coast sides of the teeth profiles.
Shipyard Layout
Most shipyards are well established and were originally sited in a suitable location for building small ships with methods which have now been superseded. With the growth in ship sizes and the introduction of new building methods it has been recognized that a revised shipyard layout will be advantageous. Advantages to be gained, apart from the ability to construct larger vessels, are primarily, a uniform work load, a shorter ship build cycle, and economies in construction practices. These are...
Shear forces and bending moments of ships
The shear force and bending moment at any section in a ship may be determined from load curve. It has already been shown that the shearing force at any section in a girder is the algebraic sum of the loads acting on either side of the section and that the bending moment acting at any section of the girder is the algebraic sum of the moments acting on either side of the section. It has also been shown that the shearing force at any section is equal to the area under the load curve from one end...
The Context Of A Process
The context of a process consists of the contents of its (user) address space and the contents of hardware registers and kernel data structures that relate to the process. Formally, the context of a process is the union of its user-level context, register context, and system-level context.1 The user-level context consists of the process text, data, user stack, and shared memory that occupy the virtual address space of the process.
Freeboard Computation
Basic freeboards are given in the rules which are dependent on the length and type of vessel. Ships are divided into types 'A' and 'B'. Type 'A' ships are those which are designed to carry only liquid cargoes in bulk, and in which the cargo tanks have only small access openings closed by watertight gasketed covers of steel or equivalent material. These vessels benefit from the minimum assignable freeboard. All ships which do not come within the provisions regarding Type 'A' ships are considered...
33 Basic Components Of An Energy Audit
An initial summary of the basic steps involved in conducting a successful energy audit is provided here, and these steps are explained more fully in the sections that follow. This audit description primarily addresses the steps in an industrial or large-scale commercial audit, and not all of the procedures described in this section are required for every type of audit. The audit process starts by collecting information about a facility's operation and about its past record of utility bills....
Detritus Tanks
Detritus tanks remove a mixture of grit and organic matter. The width and shape of the grit chamber are not critical with this design, but the surface area (which relates to settling velocity) is. The area requirements are proportional to the settling velocity of the grit particle and to the waste-water flow rate. The settled grit is conveyed to a common collection sump. A raking or conveying mechanism washes and removes the grit from the chamber in a clean and drained condition, and the...
Melting and pouring the babbitt
CASUALLY watching, a workman pouring babbitt metal into the bearing shell does not impress the observer as requiring any skill on the part of the operator. Neither does this operation seem to be such as to require any special attention or careful supervision. However, this impression is misleading,, for to produce reliable and dependable babbitted bearings, many little details, must be thoroughly mastered. Melting Babbitting outfits vary from an old kettle heated on the blacksmith forge, to a...
Recommendations on metacentric height
Ideally, the stability should be assessed using the complete righting arm curve, but since it is impossible to calculate righting arm curves without the outline design, more easily determined GM values are given as a function of the ship type, Table 1.4. If a vessel has a GM value corresponding well to its type, it can normally be assumed (in the early design stages) that the righting arm curve will meet the requirements. Table 1.4 Standard GM for 'outward journey', fully loaded Table 1.4...
Lloyd's Register Classification
All ships classed by Lloyd's Register of Shipping are assigned one or more character symbols. The majority of ships are assigned the characters 100A1 or 100A1. The character figure 100 is assigned to all ships considered suitable for sea-going service. The character letter A is assigned to all ships which are built in accordance with or accepted into class as complying with the Society's Rules and Regulations.
How Scented Flameless Candles Work
The convenience flameless candles offers, especially scented flameless candles, makes it easier for us to go on with other activities of our daily lives. But for the inquisitive mind, a question arises as to how exactly scented flameless candles work. Is the technology behind these unique candles complicated Do scented flameless candles contain little machines trapped inside each candle Can the technology of scented flameless candles be replicated Anatomy of scented flameless candles From afar...
Schwedler Dome Horizontal Polygonal Rings
A Schwedler dome also consists of meridional ribs connected together to a number of horizontal polygonal rings to stiffen the resulting structure so that it will be able to take unsymmetrical loads (Figure 24.14b). Each trapezium formed by intersecting meridional ribs with horizontal rings is subdivided into two triangles by a diagonal member. Sometimes the trapezium may also be subdivided by two cross-diagonal members. This type of dome was introduced by a German engineer J.W. Schwedler in...
A CupandBob Couette Viscometer
As the name implies, the cup-and-bob viscometer consists of two concentric cylinders, the outer cup and the inner bob, with the test fluid in the annular gap (see Fig. 3-2). One cylinder (preferably the cup) is rotated at a fixed angular velocity (Q). The force is transmitted to the sample, causing it to deform, and is then transferred by the fluid to the other cylinder (i.e., the bob). This force results in a torque (T) that can be measured by a torsion spring, for example. Thus, the known...
Minimum Design Metal Temperature MDMT
This MDMT procedure is used to determine the lowest permissible temperature for which charpy impact testing is or is not required. The ASME Code requires this be determined for every pressure vessel and the MDMT be stamped on the nameplate. While every pressure vessel has its own unique MDMT, this may or may not be the MDMT that is stamped on the nameplate.
How To Build A Mini Catapult
A catapult is a war machine used to fling a kind of projectile. Mini catapults are great toys which are very fun to play with. The easiest and simplest one that you can possibly make only involves a spoon. The only thing you need to do is leverage it using your hands. Another type of mini catapult can also be created by you, the type which is more fun when used and one which looks even more interesting.
Piston Rod Runout
Piston rod runout is a measure of how well the cylinder is lined up with the frame and, also, how well the internals of the compressor piston, rod, crosshead are lined up with each other and the frame and cylinder combination. This runout is checked and adjusted with all parts cold the ambient temperature should be in the 60 -68 F range. Prior to performing runout measurements, cylinder and support, cylinder frame head, and doghouse nuts should be properly set or torqued. Oil scraper and...
Seal Flush Plans
As previously discussed, different seal designs are used in different seal arrangements to handle a vast array of different fluid applications. In every case, the seal must be provided with a clean lubricating fluid to perform properly. This fluid can be the actual service fluid, a barrier fluid, or an injected fluid from an external source. All these options require a different flushing or piping scheme. In an ef fort to organize and easily refer to the different seal flush piping plans, the...
5121 Trimble GPS receiver specifications
At the top of the Trimble's GPS range is the NT300D, a 12-channel parallel GPS receiver, capable of tracking up to 12 satellites simultaneously and also containing a dual-channel differential beacon receiver. The equipment is capable of submetre accuracy derived from carrier-phase filtered L1 pseudo-range calculations. In addition, vessel velocity is obtainable from differentially corrected Doppler measurements of the L1 carrier. Position information is displayed on a backlit LCD screen in one...
Shafting and propellers
The transmission system on a ship transmits power from the engine to the propeller. It is made up of shafts, bearings, and finally the propeller itself. The thrust from the propeller is transferred to the ship through the transmission system. The different items in the system include the thrust shaft, one or more intermediate shafts and the tailshaft. These shafts are supported by the thrust block, intermediate bearings and the sterntube bearing. A sealing arrangement is provided at either end...
Tap Density
Tap density is defined as the density of a powder when the volume receptacle is tapped or vibrated under specified conditions. Tapping or vibrating a loose powder induces movement and separation and lowers the friction between the powder particles. This short-term lowering in friction results in powder packing and in a higher calculated density of the powder mass. Tap density is always higher than the free-flow apparent density. Tap density is a function of particle shape, particle porosity,...
Ventilation
In most ships a combination of natural and mechanical ventilation is provided in the accommodation and machinery spaces. Mechanical supply is common, and a natural exhaust may be permitted in a number of compartments but where fumes, etc., are present, for example from galleys, a mechanical exhaust is required. This is also the case with many public rooms, often crowded and where smoking is permitted. The mechanical supply is by means of light steel sheet trunking, with louvres at each outlet....
3810Spring brake units and locks
In road vehicles the foot brakes are used chiefly for stopping the vehicle and for controlling its speed on gradients and the handbrake is used almost solely for parking purposes or in conditions where the driver does not have a foot free to operate the foot brake, for example when starting on a gradient. The two systems are made independent to a considerable extent in order to meet legal requirements and no great difficulty arises in designing satisfactory systems except in very heavy vehicles...
302 Collaboration Life Cycle
Stages of the Collaboration Life Cycle Collaboration processes usually follow a unique scheme starting with the decision to collaborate. The next stages of collaboration are the selection of partners, set-up of the collaboration and the actual collaborated product development or production activities. Collaboration ends with disconnection of the infrastructure as well as the evaluation of the success of the collaboration in order to use the experiences made for further collaborations. Regular...
Drag Coefficient
When a fluid flows past a solid body or the body moves through the fluid (e.g., Fig. 11-1), the force (FD) exerted on the body by the fluid is proportional to the relative rate of momentum transported by the fluid (pV2A). This can be expressed in terms of a drag coefficient (CD) that is defined by the equation Here, p is the density of the fluid, V is the relative velocity between the fluid and the solid body, and A is the cross sectional area of the body normal to the velocity vector V, e.g.,...
Energy And Environment Dimension In Ship Manufacturing Processes
Department of Naval Architecture and Marine Engineering Faculty of Engineering, Alexandria University, Alexandria 21544, Egypt The main issues of energy and environment associated with shipyards manufacturing processes are presented. The direct and indirect demands of energy in the shipbuilding industry are clarified. The Life Cycle Analysis (LCA) in ship production is addressed with particular emphasis on the methods commonly used to reduce energy consumption and relevant harmful environmental...
2122 Stirling engine
The Stirling engine, invented by Robert Stirling, first built in 1816 and subsequently produced on a small scale, is not an internal combustion power unit. Its working gas is cycled in a closed circuit, passing through a heat exchanger on the way round. Gases such as hydrogen, helium and freon have been used in the closed circuit. Originally, it was a viable alternative to the steam engine, for example in marine propulsion, but it has yet to be proved competitive with the internal combustion...
Directional Stability And Control
It was seen in an earlier chapter that when a ship at rest in still water is disturbed in the horizontal plane there are no hydrostatic forces to return it to its original position or to increase the movement. The ship is in neutral equilibrium. When a moving ship is disturbed in yaw it is acted upon by hydrodynamic forces which may be stabilizing or destabilizing. If stabilizing, the ship will take up a new steady line of advance but unless some corrective action is applied, by using the...
Shielded Metal Arc Welding SMAW
SMAW, or stick welding, is the most common form of arc welding. In the process, a stick or electrode is placed at the end of a holder. Using electricity from the power source, an arc is struck between the tip of the electrode and the metal welding surface. The heat of the arc melts the tip of the electrode creating the filler material that is deposited as the electrode is consumed. A coated material on the electrode burns and protects the arc from the atmosphere. The burning of the coating...
Bypass Systems TypesDesign Considerations
Continuous bypass systems As the title implies, continuous bypass systems provide continuous flow whenever the pump is running, regardless of the process demand. Figure 2 illustrates a simple system, with a bypass line branching off the pump discharge upstream of the main line check valve and containing a fixed orifice dimensioned by analysis to provide minimum required pump flow. The bypass line discharges into a reservoir that is at a lower pressure than the pump discharge. The bypass line...
Km Km [NPSHaNPSHr bep fluid
Obtained from Figure 38, the factor K7 accounts for the effects of speed and configuration. As used in that chart and in Eq. 69, the term suction-specific speed Nss (or ss) FIGURE 38 Minimum continuous stable flow (MCSF) for process pumps71 FIGURE 38 Minimum continuous stable flow (MCSF) for process pumps71 does not mean that NPSH-effects are also included rather, this expresses the fact that the impeller design is affected by the designer's choice of Nss as can be seen in the case of the...
17 Tensile Properties
The tensile properties of steel are generally determined from tension tests on small specimens or coupons in accordance with standard ASTM procedures. The behavior of steels in these tests is closely related to the behavior of structural-steel members under static loads. Because, for structural steels, the yield points and moduli of elasticity determined in tension and compression are nearly the same, compression tests are seldom necessary. Typical tensile stress-strain curves for structural...
172 Sky wave propagation
Sky waves are severely influenced by the action of free electrons, called ions, in the upper atmosphere and are caused to be attenuated and refracted, possibly being returned to earth. The prime method of radio wave propagation in the HF band between 3 and 30 MHz is by sky wave. Because under certain conditions, sky waves are refracted from the ionosphere, this band is used extensively for terrestrially-based global communications. Once again, however, there is no clear dividing line between...
Intercondensers and Interreboilers
Another useful technique for reducing the utility loads is to add intermediate exchangers. Figure 4 shows the effect of adding an inter-reboiler on a McCabe-Thiele diagram. The benefit of this modification is that the reboiler heat duty is reduced by the amount of duty used in the inter-reboiler. Since the temperature level will be less than the reboiler temperature, it may be possible to use a process stream for the heating. If this heat integration is feasible, then significant savings of the...
Compressor Piston Rod Packing
Piston rod packing is almost always the full floating type. It consists of several annular cups, segmental rings, and a flange-like gland held in the cylinder head stuffing box as a complete assembly by properly proportioned studs and nuts that secure it against a sealing gasket. The segmental packing (sealing rings) is contained in the cups and is held together as an assembly by garter springs that hold the rings firmly on the piston rod. These rings are free to float in the cups. This packing...
Straightening Carbon Steel Shafts Repair Techniques for Carbon Steel Shafts
For medium carbon steel shafts carbon 0.30 to 0.50 , three general methods of straightening the shaft are available. Shafts made of high alloy or stainless steel should not be straightened except on special instructions that can only be given for individual cases. The peening method. This consists of peening the concave side of the bend at the bend. This method is generally most satisfactory where shafts of small diameters are concerned say shaft diameters of 4 in. or less. It is also the...
Scenarios 3 For Retrieval Of A Buffer In Unix
If there are no buffers on free list scenario 4 sleep event any buffer becomes free continue back to while loop if buffer marked for delayed write scenario 3 asynchronous write buffer to disk continue back to while loop scenario 2 found a free buffer remove buffer from old hash queue put buffer onto new hash queue return buffer Figure 3.4. Algorithm for Buffer Allocation b Remove Block 4 from Free List Figure 3.5. Scenario 1 in Finding a Buffer Buffer on Hash Queue algorithm brelse input locked...
How Compressor Packing Works
As previously described, a packing set consists of a series of sealing units. Compressor packing is not bottle-tight, but the amount of leakage is extremely small, a fraction of one percent of the capacity of the machine and usually within tolerable limits. In case of toxicity of the gas or danger of explosion or corrosion, leakage may be vented to a safe place. Because the individual rings will leak slightly, it is through the series of rings that the pressure is broken down from discharge to...
43 Recirculating ball steering
Steering gears with a rotating movement are difficult to house in front-wheel drive passenger cars and, in a standard design vehicle with independent wheel suspension, also require the idler arm 5 (see Fig. 4.3) and a further intermediate rod, position 6, to connect them to the pitman arm 4 the tie rods are adjustable and have pre-lubricated ball joints on both sides (Figs 4.13 and 4.14). This type of steering system is more complicated on the whole in passenger cars with independently...
Sedimentation in a Centrifugal Field
A particle moving in a circular path continuously experiences a centrifugal force, Fc. This force acts in the plane described by the circular path and is directed away from the axis of rotation. The centrifugal force may be expressed as where m is the particle mass (g) a is the acceleration (cm s 2) w is the angular velocity (radians s_1 2n rpm 60) and x is the radial distance from the axis of rotation to the particle (cm). Thus, centrifugal force is proportional to the square of the angular...
Viscosity controllers Viscotherm
The basic principle of the Viscotherm viscosity monitoring device is shown in Figure 2.24. A continuous sample of the fuel is pumped at a constant rate through a fine capillary tube. As the flow through the tube is laminar, pressure drop across the tube is proportional to viscosity. In this unit an electric motor drives the gear pump through a reduction gear, at a speed of 40 rpm. The pump is positioned in the chamber through which the fuel is passing from the heater to the fuel pumps or...
Basic Construction and Classification
The milling machine has a power-driven spindle. An arbor for holding multitooth cutters fits into the spindle. The cutting edges or teeth on revolving circular cutters remove a controlled amount of metal at each revolution of the cutter. The workpiece is mounted on a movable table and is fed against the cutter. The table can be moved either by hand-feed or by power-feed. When several cutters are mounted on the arbor, several surfaces can be machined in one operation. The knee-and-column type of...
Noncontacting Gas Lubricated Seals
The evolution of this sealing concept for pumps has its origin in gas sealing technology developed for gas compressors in the mid-1970s. The development of this technology for FIGURE 35 Common restrictive devices used with quench, or vent and drain gland plates. FIGURE 35 Common restrictive devices used with quench, or vent and drain gland plates. pumps was accelerated in the early 1990s as a way to control emissions. Eliminating the contact between the seal faces while the pump shaft is...
Stabilizers and stabilizing systems
A ship at sea has six degrees of freedom, i.e. roll, heave, pitch, yaw, sway and surge Figure 10.5 . Of these, only roll can effectively be reduced in practice by fitting bilge keels, anti-rolling tanks or fin stabilizers. A combination of fins and the inherent damping of the ship, i.e. viscous damping and the action of bilge keels. In Figure 30.7 G is the centre of gravity, B is the centre of buoyancy, W is the weight or displacement of the ship, 6 the roll angle. M, the point of intersection...
82 Gyroscopic principles
At the heart of a marine gyrocompass assembly is a modern gyroscope consisting of a perfectly balanced wheel arranged to spin symmetrically at high speed about an axis or axle. The wheel, or rotor, spins about its own axis and, by suspending the mass in a precisely designed gimbals assembly, the unit is free to move in two planes each at right angles to the plane of spin. There are therefore three axes in which the gyroscope is free to move as illustrated in Figure 8.1 In a free gyroscope none...
409Steering characteristics oversteer and understeer
The result of the above actions is that when a vehicle moves in a circular path the centre of that path does not coincide with the point of intersection of the wheel axes. This is indicated in Fig. 40.12, where O is the intersection of the wheel axes and O1 is the actual centre of rotation. The slip angles for the wheels (A1, A2, A3, and A4) will in general all have different magnitudes. If a side force P acts on a car that is travelling in a straight line XX, Fig. 40.13, that force must be...
578 Chapter Five 536 Wire coating
In wire coating (Fig. 5.51116), metal wire is covered with plastic insulation. This process requires a pay-off (input) drum, input capstan, preheater, extruder, cross-head or offset die, cooling trough, spark tester, diameter and eccentricity gauges, output capstan, and wind-up drum. The pay-off drum and input capstan unwind wire at high speeds and provide constant speed and tension. In the preheating station, a gas burner or electrical resistance heater preheats the wire to improve adhesion,...
Brittle Fracture
With the large-scale introduction of welding in ship construction much consideration has been given to the correct selection of materials and structural design to prevent the possibility of brittle fracture occurring. During the Second World War the incidence of this phenomenon was high amongst tonnage hastily constructed, whilst little was known about the mechanics of brittle fracture. Although instances of brittle fracture were recorded in riveted ships the consequences were more disastrous...
Selecting Compressor Motors
The first step in selecting motors for large compressors (1,500 hp and over) is to determine the motor voltage, speed, and enclosure type. Motor voltage selection is determined by economics and by the availability of adequate system capacity to permit motor starting without excessive voltage drop. Restrictions by the utility or by the size of the plant's generating capacity may limit the maximum drop to less than 20 . In some cases, system dips as small as 5 or less may be the maxi mum...
Wear resistant materials
The following tables give more detailed information on the materials listed in Table 18.3 with examples of some typical applications in which they have been used successfully. When selecting the materials for other applications, it is important to identify the wear mechanism involved as this is a major factor in the choice of an optimum material. Further guidance on this is given in Table 18.1. Heat-treatable. Can be lined with glass, rubber, enamels Many engineering parts, crusher cones,...
Vertical Dispersion Of Pollutants
As a parcel of air in the earth's atmosphere rises through the atmosphere, it experiences decreasing pressure and thus expands. This expansion lowers the temperature of the air parcel, and therefore the air cools as it rises. The rate at which dry air cools as it rises is called the dry adiabatic lapse rate and is independent of the ambient air temperature. The term adiabatic means that there is no heat exchange between the rising parcel of air under consideration and the surrounding air. The...
Wartsila
Introduced in 1992, the 200 mm bore 280 mm stroke Wartsila 20 engine (Figure 27.10) was designed primarily as a genset drive to replace the long-established Wartsila Vasa 22 but small-ship propulsion installations have also been logged. An output per cylinder of 130 kW to 165 kW was initially offered, depending on the nominal speed (720-1000 rev min), but subsequent power rises took the rating to 180 kW cylinder (end-1998) and 200 kW cylinder at 1000 rev min (2003). The rating increases were...
Steam Cracking Process
A typical ethane cracker has several identical pyrolysis furnaces in which fresh ethane feed and recycled ethane are cracked with steam as a diluent. Figure 3-12 is a block diagram for ethylene from ethane. The outlet temperature is usually in the 800 C range. The furnace effluent is quenched in a heat exchanger and further cooled by direct contact in a water quench tower where steam is condensed and recycled to the pyrolysis furnace. After the cracked gas is treated to remove acid gases,...
14211 Unit Melter
Figure 14.6 shows a schematic of a typical unit melter. The term unit melter'' is generally given to any fuel-fired glass-melting furnace that has no heat recovery device. Typically, the air fuel-fired unit melters are relatively small in size and are fired with two to 16 burners. Furnaces range in production from as large as 40 tons (36 metric tons) of glass per day to as small as 500 lb (230 kg) of glass per day. Larger air fuel unit melters are found in areas where fuel is extremely cheap....
Supersolidus Liquid Phase Sintering
Supersolidus LPS involves heating a prealloyed powder between the solidus and liquidus temperatures to form a liquid phase (Ref 28, 29). The fundamental difference between classic LPS and SLPS lies in the sequence of events leading to densification. A schematic of the stages in SLPS is shown in Fig. 7. In the first stage, liquid forms as a prealloyed powder is heated above the solidus temperature. The commonly observed liquid formation sites are the grain boundaries within a particle, the...
Equipment And Procedures For Evaluating Drilling Fluid Performance
Devising tests that will accurately describe how drilling fluids behave downhole is virtually an impossible task. Most drilling fluids are complex mixtures of interacting components, and their properties change markedly with changes in temperature, shear rate, and shear history. As they circulate through the borehole, drilling fluids are subjected to ever changing conditions turbulent flow in the drill pipe, intense shearing at the bit, and nominal laminar flow in the annulus at frequently...
Freeboard and sheer
The problems associated with freeboard include the 'distribution of freeboard' along the ship's length. The sheer produces a freeboard distribution with accentuation of the ship's ends. It is here (and particularly at the forward end) that the danger of flooding caused by trimming and pitching in rough seas is most acute. This is why the freeboard regulation allows reduction of the freeboard amidships if there is greater sheer. Conversely the sheer can be decreased or entirely omitted,...
Pipeline drying
Pipelines used to transport petrochemicals such as pro-pylene and ethylene must be dried in order for the delivered product to meet moisture specifications. Natural gas pipelines are usually dried to a lesser extent to prevent the formation of hydrates. It is not unusual for a petrochemical line to be dried to a dew point of 80 F. A typical dew point for a pro-pylene pipeline will be -70 F. A carbon dioxide pipeline might be typically dried to a 40 F dew point. The natural gas industry...
Lead compensator design one
Place wm at the modulus crossover frequency of 2 rad s and position the compensator corner frequencies an octave below, and an octave above this frequency. Set the compensator gain to unity. Hence wm 2rad s 1 T1 1 rad s 1 T2 4rad s K 1.0 < m 36.9 Fig. 6.34 Nichols chart for lead compensator, design one. Fig. 6.34 Nichols chart for lead compensator, design one. The Nichols chart for the uncompensated and compensated system (curve (a)) is shown in Figure 6.34 (see also Appendix 1,From Figure...
Relative Volatility
The key separation factor in distillation is the relative volatility, defined by eqn 1 . As the value of relative volatility increases, the easier it is for components to be separated by distillation. The number or theoretical stages required to separate two species to a desired degree is strongly dependent on the value of a. The variation of this parameter with pressure is shown in Figure 1 for the system ethane-propane. As seen, a is greater at low pressure than at high pressure. Therefore,...
Chelating Ligands
Metal chelators bound to chromatographic media fix the metal ion to a solid support, enabling the separation process to take place. They modulate the affinity and selectivity of the chromatographic matrix as well as its capacity for proteins. A relatively large number of such ligands exists in the literature, although only a subset of these have found routine use in IMAC. This discussion limits itself to the most common chelating ligands and new developments in the area. Table 2 presents a...
Ship Dimensions and Form
The hull form of a ship may be defined by a number of dimensions and terms which are often referred to during and after building the vessel. An explanation of the principal terms is given below After Perpendicular AP A perpendicular drawn to the waterline at the point where the aft side of the rudder post meets the summer load line. Where no rudder post is fitted it is taken as the centre line of the rudder stock.
10134 Inverted semielliptic spring centrally pivoted tandem axle bogie suspension
(Figs 10.94, 10.95 and 10.96) This type of tandem axle suspension has either one or two semi-elliptic springs mounted on central pivots which form part of the chassis side members. The single springs may be low (Fig. 10.94) or high (Fig. 10.95) mounted. To absorb driving and braking torque reaction, horizontally positioned torque arms are linked between the extended chassis side members and the axle casing. If progressive slipper spring ends are used (Fig. 10.95), double torque arms are...
Solid Bowl Conveyor Centrifuge
A conveyor centrifuge is used when the SS are coarse, high concentration cakes are required, solids loading is high, or classified solids recovery is required. The unit is flexible, easy to operate over a range of feed rates and concentrations, and requires little attention. The combination cylindrical-conical bowl ranges from a 6-in diameter for testing to 14 to 36 in for commercial units. Long bowls at more than a 4-to-1 length-to-diameter ratio have higher capacities and are commonly applied...
High Energy Milling
Vibratory, attrition, and large-diameter tumbler mills may be classified as high-energy ball mills and, as such, may be used effectively in solid-state or mechanical alloying processes. Figure 26 provides the capabilities of typical size reduction equipment for grinding a material of a given feed size to a desired product size, when the milling objective is comminution of a hard and or brittle metal or ceramic material. The following applications are suited to high-energy milling Flaking metal...
The Jameson Cell
The Jameson Sotation cell was invented by Professor Graeme Jameson at the University of Newcastle, Australia, in 1986. It was developed to a practical reality at Mount Isa Mines, Mount Isa, Queensland, and was licensed to MIM Holdings of Brisbane in 1989. To date, there are 187 installations worldwide, in 19 countries. The cell is used for roughing, scavenging and cleaning, and also for removing oil haze from solvent extraction liquors. The distribution by field of use is coal 37 copper 29...
Bosch type fuel pump
The most common fuel pump used on auxiliary diesel engines is the Bosch type. This is a cam operated jerk pump with a helical groove on the plunger to control the fuel cut-off and therefore the quantity of fuel delivered to the cylinder for combustion. These pumps can be arranged singly along the camshaft, with one at each cylinder position or they may be housed in a single block. Each pump unit contains a pump plunger and guide together with a spring loaded delivery valve and its seat....
End Fixity Coefficient Of Fuselage Truss
(1) Fig. 1 shows a portion of a steel tubular fuselage of a small airplane. The critical tension and compression load is shown adjacent to each truss member. Assuming and end fixity coefficient c 2 for all members, select tube sizes for all members of the truss. The minimum size to be used Is 3 4 - .035. The top and bottom longerons should be spliced at least once using telescoping sizes. The material is alloy steel Ftu s 95000 and truss is welded. (2) For the cantilever welded steel tubular...
Xanthan Gum XC Polymer
Xanthan gum is properly classed with the natural polymers, although it is actually obtained in its produced rather than in its natural form. Xanthan gum production method was developed at the Northern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Peoria, Illinois, in 1961. Jeanes et al129 present a recent review containing 49 references on xanthan. Xanthan is a water-soluble polysaccharide produced by bacterial action (genus Xanthomonas) on...
Elevator Links
Elevator link and link ear contact surface radii 9 Figure 4-18. Hook and swivel bail contact surface radii 9 Figure 4-18. Hook and swivel bail contact surface radii 9 Compliance. The manufacturer is responsible for complying with all of the provisions of the specification. Magnetic Particle Examination. All accessible surfaces of the main load carrying components of the equipment shall be examined by a magnetic particle examination method or technique conforming to the requirements...
625 Birfield joint based on the Rzeppa Principle
Alfred Hans Rzeppa pronounced sheppa , a Ford engineer in 1926, invented one of the first practical Fig. 6.33 Early Rzeppa constant velocity joint Fig. 6.33 Early Rzeppa constant velocity joint constant velocity joints which was able to transmit torque over a wide range of angles without there being any variation in the rotary motion of the output shafts. An improved version was patented by Rzeppa in 1935. This joint used six balls as intermediate members which where kept at all times in a...
Auxiliary steam turbines
Auxiliary steam turbines are used in turbo-generator sets and also for cargo pump and fan drives. Power outputs vary up to about 1.5 MW for generator sets. The single cylinder turbines can be arranged horizontally or vertically. Both condensing and back pressure turbines have been used, being designed for steam conditions ranging from about 6 bar to about 62 bar at 510 C. The layout for a closed feed system featured in Chapter 1 shows how turbo-generators and turbine driven cargo pumps are...
643 Explosives Mix Explosion in Mustang Nevada USA 1998 6431 Introduction
On 7 January 1998, at 0754, two explosions in rapid succession destroyed the Sierra Chemical Company's Kean Canyon plant east of Reno near Mustang, Nevada, U.S.A. killing four workers and injuring six others. Because of the loss of life and extensive damage, the United States Chemical Safety and Hazard Investigation Board (CSB) sent a team to investigate the explosion in an attempt to understand the causes of this incident. The present account is a brief summary of the comprehensive CBS (1998)...
35 Computational panel methods
In Section 3.3.7, it was shown how the two-dimensional potential flow around an oval-shaped contour, the Rankine oval, could be generated by the superposition of a source and sink on the ,v axis and a uniform flow. An analogous three-dimensional flow can also be generated around a Rankine body - see Section 3.4.4 above - by using a point source and sink. Thus it can be demonstrated that the potential flow around certain bodies can be modelled by placing sources and sinks in the interior of the...
Coupling Methods For Pump Applications
Direct Coupling Pumps are frequently directly coupled to motors, and where the pump is not close-coupled, it is usually coupled by means of a flexible coupling. The use of a flexible coupling permits minor misalignment (angular and parallel) between motor and pump shafts. The use of some older style flexible or solid couplings could cause severe radial and axial loads on the motor bearings. Since the development of the flexible disk couplings, the earlier coupling designs have largely...
Pelton Wheel Failure Modes
This simplifies to since p1 p2 and z1 z2. Note that the impulse turbine obtains its energy from a reduction in the velocity head. The largest turbine head possible and therefore the largest power occurs when all of the kinetic energy available is extracted by the turbine, giving This is consistent with the maximum power condition represented by Fig. E12.7 amp . As indicated by Eq. 1, if the exit absolute velocity is not in the plane of the rotor i.e., b lt 180 ,...
Fluidization Engineering Kunii Levenspiel Solution 100
FIG. 17-13 Two-phase model according to May Chem. Eng. Prog., 55,12, 5, 49-55 (1959) and Van Deemter Chem. Eng. Sci., 13, 143-154 (1961) . U superficial velocity, Umf minimum fluidizing velocity, E axial dispersion coefficient, and Kbe mass-transfer coefficient. of two types, the two-phase model May, Chem. Eng. Prog., 55, 12, 5, 49-55 (1959) and Van Deemter, Chem. Eng. Sci., 13, 143-154 (1961) and the bubble model (Kunii and Levenspiel, Fluidization Engineering, Wiley, New York, 1969). The...
The Space Shuttle Main Engines
The space shuttle program, which began in the 1970s, dealt with a launch vehicle that was flanked by two large solid-fueled rockets. In the middle at the base were three liquid-fueled main engines, each having nearly 500,000 lb 2.2 million N thrust and propelled by hydrogen fuel and oxygen at a mixture mass ratio of 6 1 oxygen to hydrogen . Each of these space shuttle main engines SSME's has a dedicated pumping system, consisting of a low-pressure single-stage inducer-type pump for each...
342 Kirkstall doublereduction axle
An interesting and original design by the Kirkstall Forge Engineering Company of Leeds, who manufacture axles for all kinds of vehicles, is shown in Fig. 34.5. The first reduction occurs between the worm and worm wheel, the latter being fixed to the annulus member A which is carried in bearings C and D in the axle casing the second reduction is obtained from the epicyclic action of the train consisting of the annulus A and sun S, in conjunction with the concentric spur train (not epicyclic)...
Lead-rich Alloy Microscope
Fig. 32 Examples of characteristic eutectic microstructures in slowly cooled alloys, a 50Sn-50ln alloy showing globules of tin-rich intermetallic phase light in a matrix of dark indium-rich intermetallic phase. 150x. b Al-l 3Si alloy showing an acicular structure consisting of short, angular particles of silicon dark in a matrix of aluminum. 200x. cl Al-33Cu alloy showing a lamellar structure consisting of dark platelets of CuAh and light platelets of aluminum solid solution. 180x. d Mg-37Sn...
Planning product realization processes
There are too many variations in the product realization process to provide much more than an overview. Product planning is driven by two processes - the sales process and the marketing process. The sales process promotes the organization's existing products and service and attracts enquiries, thus creating a need for an enquiry conversion process to convert customer enquiries into orders or contracts. This may require a project planning process in order to provide the customer with a viable...
Apparatus
The simplest form of sublimation apparatus consists of a beaker or porcelain dish on top of which is placed an upturned watch-glass. The beaker contains the solid to be sublimed and the underside of the watch-glass provides the surface upon which the sublimed components condense (Figure 1). A perforated filter paper is commonly placed between the beaker and the watch-glass to prevent sublimate falling back into the sample. A variant upon the above system uses an upturned funnel instead of a...
Condensate Recovery Systems
As mentioned earlier, condensate recovery systems require careful engineering to assure that they are compatible with overall plant operations, that they are safe and reliable, and that they can actually achieve their energy-efficiency potential. In this section a few of the overall planning factors that should be considered are enumerated and discussed. 1. Availability of Adequate Condensate Sources. An energy audit should be performed to collect detailed information on the quantity of...
311 Antidive and antisquat mechanisms
The anti-dive mechanism reduces the amount by which the front end of the vehicle dips or the tail rises when the brakes are applied. It can - in the case of brakes which are outside in the wheels - only be achieved if there are pitch poles Of and Or between the axles at the front, at the rear, or on both axles (Fig. 3.153). The anti-squat mechanism reduces the amount by which the tail drops on rear-wheel drive vehicles or the front end lifts (on front-wheel drive vehicles). It acts during...
Waukesha Engine Oil Cooler
When it is based on the brake power delivered, it is termed brake sfc (bsfc). Engine thermal fuel efficiency is the ratio of the work produced per cycle to the amount of fuel energy supplied per cycle that can be released by combustion. The fuel energy supplied that can be released by combustion is the product of the mass flow of fuel supplied to the engine and the heating value or energy intensity of the fuel. This may be expressed on a higher heating value (HHV) or lower heating value (LHV)...
2432 Braced Barrel Vaults
The braced barrel vault is composed of member elements arranged on a cylindrical surface. The basic curve is a circular segment occasionally, a parabola, ellipse or funicular line may also be used. Figure 24.12 shows the typical arrangement of a braced barrel vault. Its structural behavior depends mainly on the type and location of supports, which can be expressed as L R, where L is the distance between the supports in longitudinal direction and R is the radius of curvature of the transverse...
Pullin Cylinder
Figure 5.56 Two-stage screw-plunger injection-molding machine.128 through the barrel. However, injection-molding screws, unlike extrusion screws, end with a nonreturn valve. Once molten plastic flows over or through this valve, it cannot stream back toward the feed throat during the injection phase of the molding cycle. While the melt will flow out of an open nozzle, the nozzle is typically in contact with the mold. Thus, discharge from the nozzle is blocked by the sprue of Figure 5.57...
Nishiyama Wasserman Orientation Relationship
Little misorientation between the plates within any given sheaf. Where they touch, adjacent plates are separated by low-misorientation grain boundaries. The relative orientations of the bainitic ferrite and its parent austenite are always close to the classic KS Kurdjumov-Sachs, 1930 and NW Nishiyama-Wasserman, 1934 relationships Fig. 2.16 , although as will become evident later, they can never be exactly KS or NW. These two rational relations differ only by a relative rotation of 5.26 about...
37 Steer angle and steering ratio
References 1 and 9 deal with this area in detail. Section 4.7 covers steering kinematics. When the vehicle is moving very slowly and 'free of lateral forces', it will only corner precisely when the verticals drawn in the middle of all four wheels meet at one point - the centre of the bend M. If the rear wheels are not steered, the verticals on the two front wheels must intersect with the extension of the rear axle centre line at M Figs 3.89 and 1.69 whereby different steer angles Si and Sa,o...
Liquid Liquid Extraction Techniques
Separatory funnel techniques There are few limitations on what size or type of liquid samples can be extracted, except that the two liquid phases must be immiscible and unreactive with each other. Separ-atory funnels are available to handle samples from as small as a few millilitres to several litres. Extraction times vary from 1 to 15 min, depending on the specific requirements of the method, but equilibration is usually fast in all but the most viscous liquids. As noted in the section on...
46 Ribbed Domes
As pointed out in Art. 4.5, domes may be thin-shell, framed, or a combination. One type of framed dome consists basically of arch ribs with axes intersecting at a common point at the crown and with skewbacks, or bases, uniformly spaced along a closed horizontal curve. Often, to avoid the complexity of a joint with numerous intersecting ribs at the crown, the arch ribs are terminated along a compression ring circumscribing the crown. This construction also has the advantage of making it easy to...
Barrel Type Pump Image
FIGURE 5 Radially split or barrel type pump API 610 Type BB5 (Flowserve Corporation) FIGURE 6 Single stage, overhung, vertical inline pump with separate bearing frame API 610 Type OH3 (Flowserve Corporation) FIGURE 6 Single stage, overhung, vertical inline pump with separate bearing frame API 610 Type OH3 (Flowserve Corporation) minimum life requirements mentioned earlier, hydrodynamic bearings are required. This may result in a pump with sleeve radial and rolling element thrust bearings, or...
Sintering Mechanisms
Important contributions to sintering arise from diffusion and viscous flow. Diffusion rates increase with increasing temperature because of the increased number of vacancies that promote diffusion of substantial alloying elements. Sintering temperature must be held very close to the solidus temperature to attain full density in a reasonable time. A sintering temperature 5.5 to 11 C (10 to 20 F) above the solidus reportedly forms a small amount of liquid, which allows high-diffusion rates for...
Apparent Density
Apparent density of a metal powder, or the weight of a unit volume of loose powder expressed in grams per cubic centimeter, is one of the fundamental properties of a powder. This characteristic defines the actual volume occupied by a mass of loose powder, which directly affects processing parameters such as the design of compaction tooling and the magnitude of the press motions required to compact and densify loose powder. In most compacting operations, dies are filled by volume measure, and...
12 Philips Stirling Engines
Work on Stirling engines has been in progress since 1937 al the Research Laboratories of N. V. Philips Gloeilampenfabricken, Eindhoven, Netherlands, the large international company well known for electrical and electronic products. The work on Stirling engines, extending over 40 years, can be broken into distinct phases The initial phase, from 1937 to 1954, was primarily concerned with the establishment o new ideas and concepts about air engines and the development of small engines. The...
Synthol Fischer-tropsch Capital Cost Million
Where Wn weight fraction of products with carbon number n, and a chain growth probability, i.e., the probability that a carbon chain on the catalyst surface will grow by adding another carbon atom rather than terminating. In general, a is dependent on temperature, pressure, and catalyst composition but independent of chain length. As a increases, the average carbon number of the product also increases. When a equals 0, only methane is formed. As a approaches 1, the product becomes predominantly...
Subsurface Hydraulic Pumping System
A complete hydraulic system consists of a fluid cleaning system, a power pump (usually a triplex), surface controls, a subsurface hydraulic pump, and tubing connecting the surface power pump to the subsurface pump. (See Section 3.1 for a complete description of power pumps.) Figure 6 is a schematic drawing of a complete multiple-well hydraulic system. Because the pressurized power fluid supplies the energy needed to pump the well, the heavy sucker rod string and the heavy structure of the...
Aircraft Downwash
5.2.3 Variation of velocity in vortex flow To confirm how the velocity outside a vortex core varies with distance from the centre consider an element in a thin shell of air (Fig. 5.12). Here, flow conditions depend only on the distance from the centre and are constant all round the vortex at any given radius. The small element, which subtends the angle 86 at the centre, is circulating round the centre in steady motion under the influence of the force due to the radial pressure gradient....
Ring Type Joint
Also known simply as ring joint, the ring-type joint does not use a gasket to form a seal between connecting flanges. Instead a round metallic ring is used that rests in a deep groove cut into the flange face (see Figure 4-6). The donut-shaped ring can be oval or octagonal in design. As the bolts are tightened, the metal ring is compressed, creating a tight seal. Although it is the most expensive, the ring-type joint is considered to be the most efficient flange used in process piping systems....
Rear fuselage
The rear fuselage profile is chosen to provide a smooth, low drag shape which supports the tail surfaces and in some configurations the rear engine installation. The lower side of the profile must provide adequate clearance for aircraft to rotate on take-off as shown in Fig. 5.17. Initial flight tests will be used to demonstrate that maximum rotation angles are possible at the minimum unstick speed. In most designs the cabin layout will be arranged to extend into the rear fuselage, terminating...
12 Investigation Pyramid
It is for this reason that the scientific investigation and analysis of an accident, crime, catastrophic event, or failure is structured like a pyramid (Figure 1.1). There should be a large foundation of verifiable facts and evidence at the bottom. These facts then form the basis for analysis according to proven scientific principles. The facts and analysis, taken together, support a small number of conclusions that form the apex of the pyramid.
Tungsten Metal Powder Production
Industrially relevant tungsten-bearing minerals are Wolframite Mn, Fe WO4 , Ferberite FeWO4 , Hubnerite MnWO4 and Scheelite CaWO4 . The tungsten concentration of workable ore starts at 0.1 to 0.3 wt WO3. Concentrations of more than 2 wt are rare. The average WO3 content is usually about 0.5 wt Ref 11, 12, 13 . Depending on the mineral type, different techniques are used to concentrate the ore up to typical WO3 contents about 60 to 70 , such as gravity methods and flotation. An important...
45 Torque converter performance terminology
To understand the performance characteristics of a fluid drive (both coupling and converter), it is essential to identify and relate the following terms used in describing various relationships and conditions. 4.5.1 Fluid drive efficiency (Figs 4.11 and 4.12) A very convenient method of expressing the energy losses, due mainly to fluid circulation within a fluid drive at some given output speed or speed ratio, is Fig. 4.11 Characteristic performance curves for a three element converted coupling...
The Thermal Conductivity Detector
The TCD has long been a standby in packed column chromatography. It is a simple device, well suited to routine analyses where it is not necessary to detect low concentrations of components. It has been in use since the beginning of GC and has proven to be a rugged and dependable detector, in part because of the relatively simple electrical requirements. It is often encountered in less expensive instruments, and is the commonly used detector for the analysis of fixed gases. Until the...
973 Eccentric Braced Frames
These combine the strength and stiffness of a concentric braced frame with the inelastic performance of a special moment-resisting frame (Fig. 9.9c). The UBC permits use of an R of 7 or 8.5 for an eccentric braced frame. This results in seismic design forces comparable to those required for special moment-resisting frames if the fundamental period of vibration is the same. However, braced frames are invariably stiffer than moment-resisting frames of similar geometry and have a shorter period....
Pot Type Transfer Moulding
Figure 6.5 Schematic showing four steps in the vacuum potting process. with matched molds (that is, with two mold halves closed after the reinforcing material has been impregnated with the liquid to produce a smooth uniform surface on both top and bottom of the part) and with conveyors, curing ovens, etc. Figure 6.6 Hand lay-up process for producing highly reinforced parts with fiber matting and polyester, epoxy, or other thermosetting liquid resin systems. Figure 6.6 Hand lay-up process for...
Flame Hardening
Flame hardening is a rapid, economical method for selectively hardening specific areas on the surface of a part. The process is applied only to flame-hardenable materials, principally carbon and alloy steels, certain stainless steels, and cast irons. Flame hardening is used to harden parts to depths of 1 64 -1 4 in. Flame hardening is any process that uses an oxy-fuel gas flame to heat carbon or alloy steel, tool steel, cast iron, or hardenable stainless steels above a certain critical...