Flow Differences

FIGURE 6.1 shows the daily cash flows for a forward and a futures contract having identical terms. The futures contract generates intermediate cash flows the forward doesn t. As with the forward contract, the delivery price specified in the futures contract is set so that at initiation, the pres- 

FIGURE 6.1 Cash Flows for Forwards and Futures Contracts 

As illustrated in figure 6.1, the process works as follows After day one, the future price is reset from A to F. The amount (Fi - F), if positive, is handed over by the short counterparty to the long counterparty. If the amount is negative, it is paid by the long counterparty to the short. On the expiry day, T, of the contract, the long counterparty receives a settlement amount equal to Pt - F -i, which is the difference between the future price and the price of the underlying asset. The daily cash flows cancel each other out, so that at expiry the value of the contract is identical to that for a forward, that is Pj — F). 

Daily settlement has both advantages and disadvantages. If a position is profitable, receiving part of this profit daily, as happens with a futures contract, is advantageous because the funds can be reinvested while the position is still maintained. On the other hand, a losing position saddles the holder of a futures contract with daily losses not suffered by the holder of a loss-making forward position. 

Aside from how they are constructed and traded, the most significant difference between forwards and futures, and the feature that influences differences between their prices, concerns their cash flows. The profits or losses from futures trading are realized at the end of each day. Because of this daily settlement, at expiration all that needs to be dealt with is the change in the contract value from the previous day. With forwards, in contrast, the entire payout occurs at contract expiry. (In practice, the situation is somewhat more complex, because the counterparties have usually traded a large number of contracts with each other, across a number of maturity periods and, perhaps, instruments, and as these contracts expire, they exchange only the net loss or gain on the contract.) 

All market participants in exchange-traded contracts trade with a central counterparty, the exchange s clearing house. This eliminates counterparty risk. The clearing house is able to guarantee each deal, because all participants are required to contribute to its clearing fund 

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At flows different from design eonditions, there exists a eireumferential pressure gradient at the impeller tip and in the volute at a given radius. 

In an oriented porous medium, the resistance to flow differs depending on the direction. Thus, if there is a pressure gradient between two points and a particular fluid particld is followed, unless the pressure gradient is parallel to oriented flow paths, the fluid particle will not travel from the original point to the point which one would expect. Instead, the particle will drift. 

Balanced anteroom air flows Anteroom ilr flow difference < 0.024 m s" Anteroom door gap velocity > 0 m s" Anteroom smoke direction hallway to anteroom... 

Flow is generally classified as shear flow and extensional flow [2]. Simple shear flow is further divided into two categories Steady and unsteady shear flow. Extensional flow also could be steady and unsteady however, it is very difficult to measure steady extensional flow. Unsteady flow conditions are quite often measured. Extensional flow differs from both steady and unsteady simple shear flows in that it is a shear free flow. In extensional flow, the volume of a fluid element must remain constant. Extensional flow can be visualized as occurring when a material is longitudinally stretched as, for example, in fibre spinning. When extension occurs in a single direction, the related flow is termed uniaxial extensional flow. Extension of polymers or fibers can occur in two directions simultaneously, and hence the flow is referred as biaxial extensional or planar extensional flow. 

Nitridation of the oxide precursor was performed under pure ammonia flow. Different aluminophosphate oxynitrides AlPONs with variable nitrogen contents were obtained by modif3ring the time and/or the temperature of nitridation (Table 1). 

Differential thermal analysis (DTA) is a technique in which the temperature difference between the sample tested and a reference material is measured while both are subjected to the controlled temperature program. Differential scanning calorimetry (DSC) is a technique in which the heat flow difference between the sample and reference material is monitored while both are subjected to the controlled temperature program. Thermogravimetric analysis (TGA) is a technique in which the weight of a sample is monitored during the controlled temperature program. 

Olefins plants, for the most part, all have the same basic technology, but the process flows differ with the varied feedstocks that can be used. This chapter will cover in some depth the feeds, the hardware, the reactions, and the variables that can be manipulated to change the amount and mix of products. The physical properties of ethylene and propylene, which present some unique handling problems, will be covered also. 

In many processes involving reactive flows different phenomena are present at different order of magnitude. It is fairly common that transport dominates diffusion and that chemical reaction happen at different timescales than convection/diffusion. Such processes are of importance in chemical engineering, pollution studies, etc. 

It is common to split the carrier gas into two streams, sending part through the analytical column and part through a matched reference column. Each stream is passed over a different filament or alternated over a single filament. The resistance of the sample filament is measured with respect to that of the reference filament. The reference column minimizes flow differences when temperature is changed. Sensitivity increases with the square of the filament current. However, the maximum recommended current should not be exceeded, to avoid burning out the filament. The filament should be off when carrier gas is not flowing. 

Other contributions to the polarization are activation polarizations (nact) caused by inhibition of the passage of ions through the phase boundary which may arise in the discharge mechanism. Films on the electrode may also contribute (e.g. oxide, metal already deposited, impurity) by offering a resistance to current flow differing from the bath resistance (ohmic polarization, Tlohm)- Hence the observed overvoltage is given by... 

The F( + )d methods, like techniques in the F(+)cd class, require differential flow for separation. However the nature of the differential flow differs in the two cases. Since the F(+)d methods induce enrichment only at an interface between two phases, the sole requirement of differential flow is that one phase assumes motion relative to another phase. It is usually an easy matter to instigate the relative motion of phases. 

Provide uniform films because of planetary substrate rotation. The rotation tends to smooth out substrate temperature differences and gas flow differences near the substrate surface. 

Fiver disease in humans encompasses a wide range of pathological disturbances that can lead to a reduction in liver blood flow, extrahepatic or intrahepatic shunting of blood, hepatocyte dysfunction, quantitative and qualitative changes in serum proteins, and changes in bile flow. Different forms of hepatic disease may produce different alterations in drug absorption, disposition, and pharmacologic effect. The pharmacokinetic or pharmacodynamic consequences of a specific hepatic disease may differ... 

C How does turbulent flow differ from laminar flow For which flow is the heat transfer coefficient higher ... 

Relative contributions of viscous and Knudsen flow some data As will be discussed in Section 9.3, small contributions of viscous flow to the total flow in the transition region can have a considerable effect on the selectivity in separations. Therefore some typical data are given in Table 9.2. for N2 as a reference gas. Note that for light gases (H2) the contribution of the viscous flow differs considerably from that given in Table 9.2. 

These simple models based on the assumption of a single intestinal compartment have been refined to the advanced compartmental absorption and transport model that allows transit and differential expression of enzymes and transporters down the length of the gastrointestinal tract including pH, fluid, and blood flow differences [3]. The ACAT model is based on a series of integrated differential equations and has been implemented in the commercial software Gastroplus (see Chapter 17). 

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