Demand pooling

Thus, if the manufacturer could pool demands from many retailers and thus smooth inventories, it may be optimal for inventory to be held at that manufacturer. However, if the manufacturer does not see much demand pooling benefits, possibly due to differing requirements for each retailer, then the retailer may be the pooling location to smooth demands from multiple customers, which will improve supply chain performance. 

S Demand Pooling with Vendor Managed Inventory... 

The supplier clearly stands to increase his cost saving from demand pooling by increasing the number of retailers assigned to each warehouse (reduces total inventory in the system). With a dynamic restructuring capability, the supplier would be able to decide how many of its warehouses he should select for use fewer warehouses if the number of distinct retailer demands decreases. This would ensure allocation of a sufficiently large number of retailer demands to a warehouse. To implement it, the supplier would need a modified system that would enable him to open and close warehouses, as needed. Ideally, the system would pop up the open warehouses online, and enable the suppher to divert retailer demand to the warehouses in real time. 

Natural gas production and transmission systems are complemented by underground storage systems. These systems provide the capabdity to respond to short-term gas demands which exceed the immediate production levels or transmission capabdities. They also provide an opportunity to sustain some production by refilling the storage areas when seasonal temperature variations lead to periods of reduced gas demand. In the United States in 1990, there were 397 storage pools having a combined capacity of 2.2 x 10 (1). 

The basic principles of swimming-pool water treatment also apply to spas and hot tubs. However, spas and tubs are not miniature swimming pools but are unique in treatment requkements because of use patterns and a high ratio of bather to water. Eor example, four people in a 1.9-m (500-gal) spa or tub have a sanitizer demand equal to 160 people in a 75.7-m (20,000-gal) swimming pool. 

U.S. petroleum benzene prices since 1974 are Hsted in Table 6 (64). Until 1978, benzene prices were relatively stable and through 1985 they increased considerably, peaking in 1981 because of the increased demand for aromatics in the gasoline pool. At that time, there was also a large surplus of low priced imported benzene and a softening of the ethylbenzene—styrene market. The decline of cmde oil prices in 1986 caused a dramatic drop in domestic benzene prices. In 1987, U.S. benzene production increased 13.9% over 1986, and this rise was largely ascribed to a favorable export market for benzene derivatives... 

Economic Aspects. Lithium hypochlorite is produced by Lithium Corporation of America (a subsidiary of FMC) at its plant in Bessemer, North Carolina which has a capacity of about 4000 t/yr. Its total demand is low owing to its relatively high price of about 1.27/lb in tmckload quantities. Estimated U.S. consumption in 1987 was 2000—2500 t, 80—90% being used in swimming pool sanitation. 

Isobutylene (CH2=C(CH3)2) is a reactive C4 olefin. Until recently, almost all isobutylene was obtained as a by-product with other C4 hydrocarbons from different cracking processes. It was mainly used to produce alkylates for the gasoline pool. A small portion was used to produce chemicals such as isoprene and diisobutylene. However, increasing demand for oxygenates from isobutylene has called for other sources. 

The term fuel saving needs to be qualified, since the use of the heat in the water will be given to a process which may be unrelated to boiler demand. Examples of suitable applications occur in laundries, agricultural soil heating, food industries, abattoirs and swimming pool heating. 

One characteristic of regulated exocytosis is the ability to store secretory vesicles in a reserve pool for utilization upon stimulation. In the presynaptic terminal, this principle is expanded to define multiple pools of synaptic vesicles a ready releasable pool, a recycled synaptic vesicle pool and a larger reserve pool. This reserve pool assures that neurotransmitter is available for release in response to even the highest physiological demands. Neurons can fire so many times per minute because synaptic vesicles from the ready releasable pool at a given synapse undergo exocytosis in response to a single action potential. 

Those vesicles have been primed by docking at the active zone and are therefore ready for exocytosis upon arrival of an action potential. However, for the synapse to respond rapidly and repeatedly under heavy physiological demand, these exocytosed vesicles must be rapidly replaced. This is accomplished first from the recycled pool of vesicles and, as the demand increases, from the reserve pool. To be recycled, synaptic vesicles must be reloaded quickly after they release their contents. The sequence of events that is triggered by neurotransmitter exocytosis is known as the synaptic vesicle cycle [73,74] (Fig. 9-8). 

Zinc deficiency places an increased demand on selenium (Se) pools in daphnids. As little as 5 pg Se/L in zinc-free water eliminated overt cuticle damage and substantially increased reproduction, but did not alter the shortened life span. Cladocerans at the threshold of Se deficiency will become overtly Se deficient when zinc supplies are lacking (Keating and Caffrey 1989). Insufficient copper introduces cuticle problems in daphnids similar to those introduced by insufficient zinc or... 

To get a better idea of the complexity of a real application scenario in these industries it makes sense to, once, exemplarily depict the planning processes in a typical production of active pharmaceutical ingredients (API production). Most pharmaceutical companies are looking at planning scenarios in which several hundred individual resources or facilities have to be accounted for, with demands and orders for some thousand final products. The planning horizon is often set to 2-5 years. Next to single equipment, there are facility pools, with one pool consisting of several individual units. 

The standard deviation can be used as a measure of risk. For example, if we pool the risk of random demands by several customers in one warehouse, the above formula indicates that the risk increases slower than the mean demand. It is therefore generally a good idea to pool risks. 

The hydrogenation of enamides and enol acetates without acid function is often more demanding, and at present is not applied widely. Besides a bench-scale application by Roche with a Ru-biphep catalyst [55], two examples are of interest a pilot process for a cyclic enol acetate by Roche [55], and a feasibility study by Bristol-Myers Squibb [56], both using Rh-DuPhos catalysts (Fig. 37.11). In the latter case, despite very good ee-values, a chiral pool route was finally chosen. Chiral Quests Rh-f-KetalPhos (see Fig. 37.9) has been shown to hydrogenate a variety of substituted aryl enamide model substrates at r.t., 1 bar, with very promising catalyst performance (ee 98-99%, TON 10000) [47]. 

Af-Acyliminium ions are known to serve as electron-deficient 4n components and undergo [4+2] cycloaddition with alkenes and alkynes.15 The reaction has been utilized as a useftil method for the construction of heterocycles and acyclic amino alcohols. The reaction can be explained in terms of an inverse electron demand Diels-Alder type process that involves an electron-deficient hetero-diene with an electron-rich dienophile. Af-Acyliminium ions generated by the cation pool method were also found to undergo [4+2] cycloaddition reaction to give adduct 7 as shown in Scheme 7.16 The reaction with an aliphatic olefin seems to proceed by a concerted mechanism, whereas the reaction with styrene derivatives seems to proceed by a stepwise mechanism. In the latter case, significant amounts of polymeric products were obtained as byproducts. The formation of polymeric byproducts can be suppressed by micromixing. 

This reduction in the proportion of profits consumed has important consequences for the economy as the simulation is repeated over subsequent periods. Although Bauer was able to demonstrate that expanded reproduction is sustainable over a four-year period Grossmann showed that if the simulation is continued for 35 years then this results in economic breakdown. Table 7.1 shows a steady fall in the proportion of profits consumed until, in year 34, only 2.16 per cent are consumed. The stringent demands of capital accumulation are fulfilled with constant and variable capital increasing by 10 and 5 per cent respectively throughout the 35-year period. The problem, however, is that with variable capital failing to keep pace with constant capital the pool of surplus value extracted from variable capital also fails to keep pace. 

---