The effect of implementation of the ISO 9000 on customer complaints; a 5-year follow-up study in a regional laboratory.

Although the importance of quality management in the medical laboratory has been emphasized, we are unaware of any interventional studies demonstrating benefits of implementation of recommendations of the International Standards Organization (ISO). In the following 5-year follow-up study, we implemented quality management as stipulated by the ISO, received a certificate of approval, and determined how the program affected customer complaints. From 1997 to 2001 there was only a slight decrease in the number of customer complaints, but a significant continuing downward trend in the proportion of justified complaints (chi-squared test, p<0.001). In fact in 2001 the proportion of justified complaints had decreased by nearly 80% (relative risk, 0.22; 95% confidence interval, 0.09–0.52)), to only 10.9% of the total complaints. We conclude that the use of the ISO 9000 along with good laboratory practice resulted in a significant decrease in the proportion of justified complaints.     

Chromium(VI) Based Oxidants III.1,2 Ferric Dichromate,Polyvinylpyridine Supported Zinc,and Ferric Dichromates as New Oxidizing Agents

Ferric dichromate, polyvinylpyridine supported zinc and ferric dichromates complexes are prepared and used as stable, mild, and efficient oxidizing reagents for the oxidation of different organic compounds. Ferric dichromate complex is more efficient.     

Application of Nanocrystalline Iranian Diatomite in Immobilized Form for Removal of a Textile Dye

The aim of the present investigation was to immobilize nanocrystalline diatomite within calcium alginate matrix for the adsorption of Direct Red23 (DR23) in aqueous media. Scanning electron microscopy (SEM), x-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy were used to characterize the samples. As a result, the adsorption process obeyed pseudo-second-order kinetic model (R² = 0.9934) and Langmuir isotherm model (R² = 0.9732) with a maximum adsorption capacity of 24.10 mg/g. The value of mean free energy (15.81 kJ/mol) demonstrated that the process has been taken place chemically. As the adsorbent dosage increased from 0.5 to 3.0 g/L, the decolorization efficiency (%) increased from 26.0 to 75.5%, respectively. Inversely, the decolorization efficiency (%) decreased from 98.0 to 29.0% with increasing initial dye concentration from 5 to 160 mg/L, respectively. The negative values obtained for Gibbs free energy (ΔG°) and positive value of enthalpy change (ΔH°) indicated spontaneous and endothermic nature of the process.     

Phosphinic Acid Analogues of Thiaproline and the Related Heterocyclic Aminophosphinic Acids

Bis(trimethylsilyl) phosphonite adds in a 1,2 fashion to the C = N bond in 3-thiazolines 3a-d to give after hydrolysis phosphinic acids 5a-d. Starting from 3-oxazines, the corresponding 6a,b phosphinic acids 7a,b were obtained.     

Characterization of Zinc Ion Transport Via Dialysis Process

Treatment of metal ions' wastes is getting more interest due to the tight regulations for environmental protection. Dialysis, a membrane based process with the concentration difference as the driving force, may be used for separation of metal ions from wastewater. In this study membranes with different pore sizes including Accurel, Celgard, GVHP, PM30 and PTHK membranes were employed to characterise the transport of zinc ion in various (0.01, 0.1, 0.5, 1, 5 and 10 w/v percent) initial feed concentrations. The results show that low initial feed concentration causes less passage of ions through the membrane due to low driving force, i.e. concentration gradient across the membrane. This result is expected. However the effect of membrane pore size is somehow unexpected. It was found that the large pore size membranes provide less penetration of the metal ions through the membrane. This reproducible result has been explained based on the transport mechanism. Two types of mechanisms, i.e. extensive and intensive mechanisms, have been suggested for metal ion transport through different pore size membranes.     

Using generating functions to convert an implicit (3,3) finite difference method to an explicit form on diffusion equation with different boundary conditions

In this article, our main goal is to develop an idea to convert an implicit (3,3) ??-scheme finite difference method to an explicit form for both linear and nonlinear diffusion equations and also for nonlinear advection-diffusion equation with different boundary conditions. Accordingly, we assist power series generating functions which are a routine method in discrete mathematics. Also, the stability analysis of ??–scheme to implement in nonlinear advection–diffusion equation has been investigated. Finally, the new approach has been implemented for Fisher, reaction–diffusion, Burgers and coupled Burgers equations as test problems to verify the ability and efficiency of the method proposed in this paper.     

Slender body expansions in potential theory along a finite straight line

Consider a distribution of singularities in a potential field along a finite straight line such that the potential satisfies the Laplace equation. An example is a distribution of sources representing a ship or missile moving with forward velocity in a potential inviscid flow field. Such bodies are often truncated or bluff at the ends, and so the strength of the resulting distributions may not gradually tend to zero close to these ends and may instead be non-zero finite. A near-field expansion is obtained which accounts for this using the slender body theory integral splitting method. All terms in the expansion are obtained, and the coefficient of each term in the infinite sequence is given in terms of differentials of the distribution strength. Hence an exact separation of variables solution (separating the axial distance from the cross-sectional distances) is obtained for the potential. This is different from previous representations in that it represents a distribution over a finite length, and the resulting expansion is a simple single summation expression that is straightforward to apply. The resulting numerical scheme is discussed, in particular the evaluation close to the ends and also a comparison between the presented slender body theory and existing numerical methods.