First fixed charge

The Trustee will create security over the assets of the issuer (including, without limitation, the Collateral Debt Securities, Eligible Investments and cash accounts). Such security will be by way of first fixed charge and will be for the benefit of all the secured parties including the Noteholders. If there is an event of default under the Notes, the security will become enforceable and the Trustee will be involved in liquidating the assets in order to meet the claims of the various creditors in accordance with a predetermined order of priority of payments. The Trustee is also responsible for acting on behalf of the Noteholders in order to make sure any amendments to any documents and the like are not prejudicial to the Noteholders. 

Below we present a well-known calculation of membrane potential based on the classical Teorell-Meyer-Sievers (TMS) membrane model [2], [3]. The essence of this model is in treating the ion-selective membrane as a homogeneous layer of electrolyte solution with constant fixed charge density and with local ionic equilibrium at the membrane/solution interfaces. In spite of the obvious idealization involved in the first assumption the TMS model often yields useful results and represents in fact the main tool for practical membrane calculations. We shall return to TMS once again in 4.4 when discussing the electric current effects upon membrane selectivity. In the case of our present interest, the simplest TMS model of membrane potential for a 1,2 valent electrolyte reads... 

Deviations from EVM behaviour at low Cs (high a) values were first described successfully in terms of a non-uniform charge distribution by Glueckauf n2), who postulated the existence of equipotential microregions each characterized by a local concentration of fixed charged groups CFL. It was further postulated that CKL conforms to the following distribution function... 

Complete neglect of the Coulomb interaction between charges fixed on the network is also a problem. It has been argued [33] that the contribution from fixed charges to the osmotic pressure plays an important role in determining the swelling equilibrium of gels. However, we will not discuss these theoretical problems further because the main concern of the present article is to clarify experimentally the nature of the first-order transition rather than to improve theoretical treatment. 

The first scientific paper on ED was published in 1903 by Morse and Pierce (Shaposhnik and Kesore, 1997), but the quantitative theory of charged membranes was available only 50 years later (Teorell, 1953). It incorporated the electrostatic repulsion of co-ions from the fixed charges... 

Adopted from the state-of-the-art in RO, TFC membranes have become increasingly interesting for UF as well. One of the first examples of a commercial membrane of this type is composed of a thin barrier layer from regenerated cellulose on a porous polyolefine support [32]. Significant increase in selectivity in protein UF via electrostatic exclusion in addition to size exclusion has been achieved by introducing fixed charges into the barrier layer of a cellulose-based TFC membrane [33]. 

One s first reaction is to reject the adequacy of casting the problem as a linear one, but, as Grossmann and Santibanez show, the use of discrete (zero/one) decisions allow one to include to a very good approximation many of the nonlinearities. For example, a zero/one variable can be associated with the existence or non-existence of a unit. In the cost function that discrete variable can cause one to add in a fixed charge for the unit only if it exists. Also one can define a continuous "flow11 variable for the unit which can be forced to zero if the unit does not exist by the linear constraint ... 

Let us consider first the case the fixed charge in the membrane phase arises from the dissociation reaction... 

A multiple-effect evaporator is to be used for evaporating 400,000 lb of water per day from a salt solution. The total initial cost for the first effect is 18,000, and each additional effect costs 15,000. The life period is estimated to be 10 years, and the salvage or scrap value at the end of the life period may be assumed to be zero. The straight-line depreciation method is used. Fixed charges minus depreciation are 15 percent yearly based on the first cost of the equipment. Steam costs 1.50 per 1000 lb. Annual maintenance charges are 5 percent of the initial equipment cost. All other costs are independent of the number of effects. The unit will operate 300 days per year. If the pounds of water evaporated per pound of steam equals 0.85 x number of effects, determine the optimum number of effects for minimum annual cost. 

We first treat the case in which the fixed-charge density ZeN is low. Then Eqs. (4.50) and (4.51) are linearized to give... 

The first term represents net increase of value of the product over the raw material, the second is the cost of heating, the third includes the cost of separation and return of the unreacted A, and the fourth the fixed charges. 

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