EVALUATING SOFTWARE OUTSOURCING OPTIONS Do Your Software Operations Add Value ?

If you don't know the current productivity rates, usage volumes, and other quantitative baseline data for your software operations, then software might not be a key component of the company's core business. The evaluation criteria in this article can help the IS executive determine the outsourcing options for software operations.     

The rationale for cementless total hip replacement

Current cementing techniques of distal plugging, pulsatile water cleaning of the canal, and retrograde filling with PMMA in a low-viscous state prepared using porosity reduction techniques and then pressurized have been shown to give excellent results at 10 or more years after operation. However, physical and aging characteristics of PMMA do not guarantee that those results will hold up in the 20- to 30-year time frame. Fifteen-year experience with bony ingrowth systems indicate the development of a durable interface without PMMA, although the interface does appear more vulnerable to attack by the biologic reaction to HMWPE debris. Bone remodeling appears more favorable around proximally fixed bone ingrowth prostheses than around distally fixed prostheses. Softening of the physical characteristics of the stem tip may reduce the incidence of thigh pain. Patients with high activity potential and a life expectancy of greater than 25 years should be strongly considered for a proximally fixed bone ingrowth or ongrowth prosthesis.     

Area- and time-specific marginal capacity costs of electricity distribution

Marginal costs of electricity vary by time and location. In the past, researchers attributed the variations to factors related to electricity generation and transmission. These authors, however, have not analyzed possible variations in marginal distribution capacity costs (MDCC). The objectives of this paper are:

1. (i) to show that large MDCC variations are due to the dispersion in distribution capital expenditures by time and space,

2. (ii) to propose a method for quantifying the area- and time-specific MDCC in the presence of lumpy investments, and

3. (iii) to compare our MDCC estimates to those commonly used in the electric utility industry.

Our proposed method and its results were adopted by the California Public Utilities Commission (CPUC) in 1992 for Pacific Gas and Electric Company (PG&E), the largest privately owned electric utility in the U.S.     

Control of free-radical emulsion polymerization of methyl methacrylate by oxygen injection. II. Experimental study

Oxygen injection has been proposed and experimentally demonstrated as an effective control measure for limiting the rate of heat release and altering the rate of polymerization in emulsion processes. A detailed mathematical model has been previously developed to describe the system behavior with and without oxygen injection. A simple lab scale apparatus was constructed and run extensively. Only trace quantities of oxygen are needed to inhibit the reaction completely. The facile response makes this method attractive for fast temperature control. However, because of the rapid penetration of dissolved oxygen into the polymer particles, growing radical chains are terminated prematurely, lowering product molecular weights. To minimize this detrimental effect, pulsed oxygen control is used and extensive experimental work was performed to determine the effects of controller set points on molecular weight. Moderate oxygen flows and moderate set point temperatures are found to give the optimal response without significant lowering of the final molecular weight. Injected quantities agree well with the order-of-magnitude sparging calculations needed to completely stop initiation. However, complete agreement between model simulations and experimental results was not reached due to an unmeasured loss of monomer from the reactor. Chain transfer to monomer is found to be important in modeling the polymer molecular weight. It has, however, a negligible effect on the reaction rate.     

Thermomechanical behaviour of composites

This paper derives the governing equations for the thermomechanical behaviour of composites. When the basic equations for the thermoelastic behaviour of solids were first derived in the nineteenth century several approximations were made. The effect of these assumptions are discussed and illustrated by the results of a simple laboratory test. The implications of this work on the analysis of impact damaged laminates are then discussed.     

Nanostructured polymer blends: Synthesis and structure

Nanostructured polymer blends prepared via anionic ring opening polymerizations of cyclic monomers in the presence of a pre-made polymer melt exhibit a number of special properties over traditional polymer blends and homopolymers. Here, we report on a simple and versatile method of in situ polymerization of macrocyclic carbonates in the presence of a maleic anhydride polypropylene (mPP) matrix and a surface-active compatibilizer (i.e. PC grafted onto a mPP backbone generated in situ) to yield a micro- and nanostructured polymer blends consisting of a polycarbonate (PC) minor phase, and a polypropylene (PP) major phase. By varying the processing conditions and concentration of the macrocyclic carbonate it was possible to reduce the size of the PC dispersions to an average minor diameter of 150 nm. NMR and TEM characterizations indicate that the PC dispersions do not influence crystal content in the PP phase. Overall, the results point to a simple strategy and versatile route to new polymeric materials with enhanced benefits.