Quality Control Methods for Several Related Variables

The methods described in an earlier article devoted to control methods for two related variables are extended to the case of more than two related variables. The concept of matrix notation is introduced because of the resultant simplification in multivariate analysis and the original two-variable problem is restated in matrix form. The method of principal components is introduced both as a method of charscterizing a multivariate process and as a control tool associated with control procedures. These methods are illustrated with a numerical example from the field of ballistic missiles. Approximate multivariate techniques, designed to simplify the administration of these control programs, are also discussed.     

EFFECTS OF H/C RATIO AND MOLECULAR WEIGHT ON MICROCARBON RESIDUE OF VACUUM RESID SUB-FRACTIONS

ABSTRACT

Studies in the literature have reported correlations of Microcarbon Residue (MCR) either with hydrogen to carbon atomic ratio (H/C) or with the number average molecular weight (M_n). The MCR value can be an indication of die coke yield in a commercial coking process. In this work a single correlation of MCR widi both H/C and M_n has been presented. Vacuum residue distillation fractions from hydroprocessing experiments were separated into five sub-fractions by preparative scale gel permeation chromatography, and characterized in terms of H/C, M?and MCR. In accordance with other correlations it was confirmed that increasing the H/C atomic ratio will decrease coke formation (MCR)- In addition this work has shown that for identical H/C ratio, molecules with smaller M_n values will produce less coke than those with larger M_n; values.     

Determination of the Surface Energy Distributions of Different Processed Lactose

Particulate interactions between drug and lactose carrier in dry powder inhaler formulations are affected by the heterogenous energy distribution on the surface of the individual compounds. A new method based on Inverse Gas Chromatography at finite concentration is applied to study the energy heterogeneity of untreated, milled, and recrystallized lactose of similar particle size distribution. Energy distributions for the dispersive surface energy and the specific free energy of ethanol are obtained. Milling causes an increase in surface energy due to formation of amorphous regions. Untreated and recrystallized materials have similar surface energies at low surface coverages but show clear differences in energy distribution.     

Indirect heating strategy for laser induced hyperthermia: An advanced thermal model

A novel heating strategy based on laser irradiation of surrounding tissues as an alternative to direct irradiation of superficial tumors is proposed and analyzed for the first time. The computational analysis is based on two-dimensional axisymmetric models for both radiative transfer and transient heat transfer in the human body. A diffuse component of the radiation field is calculated using P₁ approximation. Coupled transient energy equations and kinetic equations for composite human tissue take into account the metabolic heat generation and heat conduction, blood perfusion through capillaries, the volumetric heat transfer between arterial blood and tissue, the thermal conversions in blood and tumor tissue, the periodic laser heating, and also heat exchange between a human body and ambient medium. An example problem for a superficial human cancer has been solved numerically to illustrate the relative role of the problem parameters on the transient temperature field during hyperthermia treatment. In particular, the effect of embedded gold nanoshells which strongly absorb the laser radiation is analyzed. It is shown that required parameters of tumor hyperthermia can be also reached without gold nanoshells.     

Mussel and oyster culture in Saldanha Bay, South Africa: potential for sustainable growth, development and employment creation

Worldwide declines in fish stocks have a significant impact on the livelihoods of coastal fishing communities as jobs are lost and alternative forms of employment are limited. Mariculture (marine aquaculture) is considered by governments to be a viable solution to address unemployment and poverty in such communities. In Saldanha Bay, South Africa, the growing mussel and oyster industry has considerable potential for poverty alleviation, hence food security enhancement. In the first part of this study, we examine the potential ecological carrying capacity of the Bay to produce bivalves, and estimate the impact of this on employment creation should the sector’s growth potential be fully realised. This growth potential could take the sector to 10 to 28 times its current size, providing direct employment for 940 to 2,500 people in the Saldanha area. Secondly, we assess five factors that affect the sustainable growth, development and employment creation potential of small-scale mariculture in South Africa and other countries. These are state support, markets, funding, the natural environment and the local community. Participants in the sector perceive its expansion potential to be hampered by regulatory issues such as incomplete implementation of a cohesive and accessible financial support policy, slow processing of mandatory samples required to monitor product safety, poor facilitation of access to international markets, price undercutting by imports subsidized in their countries of origin, and injuriously high lease fees for water levied by the parastatal harbour authority, coupled with lack of medium- and long-term lease tenure. The risk of environmental degradation from competing harbour use by large, fossil fuel and ore transport industries is of potential future concern.