Selecting Carriers

Given bids from many independent carriers that specify the rate by lane or by groups of lanes, the minimum expected number of trucks by lane segment, the demands for trucks by lane, as well as the maximum rate the shipper would be willing to pay per lane, the goal of the model is to help the shipper select a prescribed number of different carriers that will satisfy carrier demand at minimum cost. 

Suppose 1 refers to the reservation rate for lane / (the reservation rate for a package k, would be the sum of the reservation rates for the lanes in the package) refers to the minimum dollar amount needed by firmy to supply package h, refers to the capacity estimated by firm for package k, U(j) is firm/s total capacity J /is 1 if firm/s package k contains lane / as part of the package and 0 otherwise is 1 if firm/s package k is selected, 0 otherwise. 

The model described above permits the shipper to incorporate carrier cost structure into the choice of carriers that will minimize costs. There have been several experimental investigations of such bidding schemes that will provide outcomes that maximize carrier surplus. The approaches used by Sears and the Home Depot represent two such schemes. 

For supply chains, transportation flows enable products or components to change location, thus enabling them to be used at their demand points. The timing of these transportation flows in turn interacts with transport capacity and chain structure to impact supply chain performance. Given this interaction, the total supply chain impact of a choice of transportation flows has to include transport costs, cycle stock costs, safety-stock costs, and in-transit inventory costs. For each possible transport mode, there are 

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The optical sensors are composed of ion-selective carriers (ionophores), pH indicator dyes (chromoionophores), and lipophilic ionic additives dissolved in thin layers of plasticized PVC. Ionophores extract the analyte from the sample solution into the polymer membrane. The extraction process is combined with co-extraction or exchange of a proton in order to maintain electroneutrality within the unpolar polymer membrane. This is optically transduced by a pH indicator dye (chromoionophore)10. 

In the case of ion-exchange, a selective carrier (e.g. valinomycin for potassium) extracts the cation into the polymer layer (Figure 5 and Tablel 1). 

It should be noted that selective carrier facilitated transport experiments involving the crown ethers and their derivatives have not been... 

Adsorption and persistence in plants can be modified by other chemicals or by selected carriers, although mechanisms to account for these phenomena are unclear. The application mixture influences adsorption and persistence of fenvalerate. For example, interception and persistence in sugarcane were increased when fenvalerate was applied in a 25% water/75% soybean oil mixture vs. water or soybean oil alone (Smith et al. 1989). Also, biocidal properties of fenvalerate residues on cotton foliage were increased up to 100% due to enhanced persistence of fenvalerate in the presence of toxaphene (Brown et al. 1982). 

D1.3 reserve inventory determine delivery date D1.4 consolidate orders D1.5 plan build loads D1.6 route shipments 1.7 select carriers rate shipments 1.8 receive product at warehouse D1.9 pick product D1.10 load vehicle, generate ship docs, verify credit ship product... 

There is thus a complicated interplay of the thermodynamics and kinetics of complexation, lipophilicity, diffusion and interface phenomena. Synthetic ligands are of special interest since, in principle, stepwise variations in the different parameters may be brought about via structural modification of the carrier. An efficient and selective carrier should have the following features (see also 16, 134) ... 

The structure of a first neutral Ca2+-selective carrier 116) developed along these lines is shown in Fig. 21. The interactions of this ligand... 

TABLE 1. Transfection Efficiencies for Selected Carriers Using EAhy 926, HSVEC 1, and HEK 293 Cell Lines and the Step 2 and Step 5 Products... 

A series of ion-selective membrane electrodes based on neutral carrier solvent polymeric membranes has been designed for the potentiometric determination of ion activities (for reviews see Refs. 52, 65). Systems with analytically relevant selectivities for Li+, Na+, K+, NHJ, Ca2+, and Ba2+, are available. In agreement with the treatment given in Sections III and IV, the ions preferred in potentiometric studies may be transported preferentially through the same membranes in electrodialytic experiments. So far, selective carrier transports have been realized for Li+, Na+, K+, and Ca2+. 

Materials with selective binding or transport properties will have a major impact on sensor design and fabrication. Selectivity in either binding or transport can be exploited for a variety of measurement needs. This selectivity can be either intrinsic, that is, built into the chemical properties of the material, or coupled with selective carriers that allow a non-selective material to be converted into a selective one (see the section on recognition chemistry). An example of the latter is the use of valinomycin as a selective carrier in a polyvinyl chloride membrane to form a potentiometric potassium ion sensor. Advances in the fields of gas separation materials for air purification and membrane development for desalinization are contemporary examples illustrating the importance of selective materials. As these materials are identified, they can be exploited for the design of selective measurement schemes. 

Asfari, Z., Bressot, C., Vicens, J., Hill, C., Dozol, J.-F., Rouquette, H., Eymard, S., Lamare, V., Toumois, B. Doubly Crowned Calix[4]arenes in the 1,3-Altemate Conformation as Cesium-Selective Carriers in Supported Liquid Membranes. Anal. Chem. 67 (1995), 3133-3139. 

The discussion in Section 4.4.1.3 on transport mechanisms in SLM has manifestly demonstrated another facet of tuning analyte-selective extraction. For example, Figure 4.5 clearly demonstrates the selective extraction of a basic compound—all that is required here is a simple adjustment of the pH on either side of the membrane. Also, Figure 4.6 neatly illustrates the possibility of performing such selective extraction of anionic and cationic species in another transport mechanism that employs selective carriers. Thus, by fine-tuning the chemistry/composition of the sample, membrane liquid, and acceptor phases, analyte-selective extraction can be tailor-made. 

Detailed reports of n-type Si-doping of AlxGai.xN were also limited until recently. Details of the electrical and other properties of these doped films are usually limited to a few selected carrier concentrations and alloy compositions. Murakami et al [10] achieved Si-doping of Alo.1Gao.9N by MOVPE with carrier concentrations of 6 x 1017 and 2 x 101 cm 3, with mobilities (calculated from resistivity data) of 40 and 180 cm2/V s. Khan et al [11] also demonstrated MOVPE growth of Alo.09Gao.91N doped with silicon. Hall-effect measurements of these films revealed a mobility of 35 cm2/V s and a donor concentration of 5 x 101 cm 3. 

Composition blend of selected carrier substances based on biphenyl and esters... 

It is necessary to develop complexation chemistry and new selective carriers or to improve existing ones for improving separation and transport properties, required to optimize the OHLM processes. 

Shukla, J.P. and Misra, S.K., Studies on the selective carrier-mediated transport of plutonium (IV) ions through tributyl phosphate/ dodecane hquid membranes. Ind. J. Chem. 31 A, 323, 1992. 

A third class of ion-selective carriers consists of so-called charged carriers or associated ion exchangers. Unlike the simple ion exchangers, however, the selectivity of charged carriers is dictated by the degree of association of the analyte ion with the carrier as well as the partitioning of the analyte into the membrane... 

Table 1 Properties of selected carriers used in the design and production of hot-melt extruded dosage forms...

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