Granulation of a fuzzy set: Nonspecificity

Granulation (decomposition) of a fuzzy set A defined on a finite set of objects X is studied. Two types of decomposition are considered: external granulation determined by a given equivalence relation on X and internal granulation created by clusters of elements from X with similar membership grades in A. Axiomatic definitions of measures of granular nonspecificity and granular specificity are proposed. Some general approaches to the construction of measures of granular nonspecificity (specificity) are suggested. Relationship between granular nonspecificity, roughness and nonspecificity of a fuzzy set is discussed.     

Albendazole solution formulation via vesicle-to-micelle transition of phospholipid-surfactant aggregates

Objective: To reveal the physicochemical mechanisms governing the solubilization of albendazole in surfactant and phospholipid-surfactant solutions and, on this basis, to formulate clinically relevant dose of albendazole in solution suitable for parenteral delivery.

Significance: (1) A new drug delivery system for parenteral delivery of albendazole is proposed, offering high drug solubility and low toxicity of the materials used; (2) New insights on the role of surface curvature on albendazole solubilization in surfactant and surfactant-phospholipid aggregates are provided.

Methods: The effect of 17 surfactants and 6 surfactant-phospholipid mixtures on albendazole solubility was studied. The size of the colloidal aggregates was determined by light-scattering. The dilution stability of the proposed formulation was assessed by experiments with model human serum.

Results: Anionic surfactants increased very strongly drug solubility at pH?=?3 (up to 4?mg/mL) due to strong electrostatic attraction between the oppositely charged (at this pH) drug and surfactant molecules. This effect was observed with all anionic surfactants studied, including sodium dodecyl sulfate, double chain sodium dioctylsulfosuccinate (AOT), and the bile salt sodium taurodeoxycholate. The phospholipid-surfactant mixture of 40% sodium dipalmitoyl-phosphatidylglycerol +60% AOT provided highest albendazole solubilization (4.4?mg/mL), smallest colloidal aggregate size (11?nm) and was stable to dilution with model human serum at (and above) 1:12 ratio.

Conclusions: A new albendazole delivery system with high drug load and low toxicity of the materials used was developed. The high solubility of albendazole was explained with vesicle-to-micelle transition due to the larger interfacial curvature preferred for albendazole solubilization locus.     

What to expect from heavy clay?

The need of testing the quality of brickclay arises in all brick factories, with the opening of new deposits. The analyses are both time and economically consuming, so the aim of this study was to shorten the procedure using the already known data. This study was focused on determining the usability of heavy clays, when only the raw material major elements chemical composition is determined. The effects of chemical composition, firing temperature, and several shape formats of laboratory samples on the final properties were investigated. Chemical composition of major elements was determined on the basis of classical silicate analysis. Firing was conducted in an oxidizing atmosphere, while maintaining all other experimental conditions constant, except the final temperature. Principal component analysis (PCA) was used to determinate groups of samples according to similarity of chemical composition. Prediction of compressive strength (CS) and water absorption (WA) was done by developing five artificial neural networks (ANN). The average regression coefficients r² were used to explore the confidence level of the models. Developed models were able to predict CS and WA in a wide range of chemical composition and temperature treatment data, and the highest average r² of 0.923 for CS was obtained, while r² for WA was 0.958. The wide range of processing variables was considered in the model formulation, and its easy implementation in a spreadsheet using a set of equations makes it very useful and practical for CS and WA prediction. As it is known from literature, all the parameters entered this analysis are dependent on each other, but their mutual relationship was not quantified yet. Most importantly—the developed neural networks can be used on a global scale.     

Trace metal concentrations in Mediterranean blue mussel and surface sediments and evaluation of the mussels quality and possible risks of high human consumption

The concentrations of trace metals (Fe, Zn, Mn, Ni, Cu, Co and Cr) were determined for the first time in Mediterranean blue mussels (Mytilus galloprovincialis) and surface sediments. The mussel and sediment samples were collected from five sites on the Montenegrin coastal area (southeastern Adriatic Sea) in the fall of 2005 and 2006. The collected samples were digested with a microwave digestion system. The maximum Fe, Zn, Mn, Ni, Cu, Co and Cr mean concentrations in the mussel samples were 603.0, 345.0, 85.0, 18.9, 17.2, 9.1 and 4.2 mg/kg of sample dry weight, respectively. The maximum Fe, Mn, Cr, Ni, Zn, Cu and Co concentrations in the sediment samples were 40867, 943.0, 382.0, 336.0, 67.2, 24.8 and 16.9 mg/kg of sample dry weight, respectively. A correlation between the metal levels found in the mussel soft tissues with those found in sediments, for both 2005 and 2006, could be established, except for the levels of Zn observed.     

New assembling technique for BGA packages without thermal processes

A new assembling technique for flip-chip mounting without heating processes was developed. The proposed construction is an FR4 substrate with ring shaped connectors. It is a typical flip-chip technology. The chip is placed, with its active part face-down, directly on to the connecting areas of the substrate. The electrical connection is obtained through a mechanical contact between the ring-shaped clips and the chip bumps. The main advantage of the ring-clip-bump attachment technique is the possibility for multi-chip modules repairing without thermal processes. It is a lead-free assembling technology involving only “conventional” processes.     

Comprehensive approach to the influence of frequently used secondary raw materials on clay bricks quality using mathematical modeling (a systematic review)

The main idea of this research was to evaluate rice and sunflower hulls, sawdust and their ashes, as additives in clay brick production using mathematical analysis. All available papers, containing the parameters of interest, were used in the study, which consisted of total 316 cases, obtained from the literature. The major oxide content of clays and mixtures, then weight percent addition and particle size ranges of secondary raw materials, and process parameters (firing temperature, soaking time and average heating rate) were selected as inputs to mathematical models. Shaping moist was the only parameter characterizing transition state of the products analyzed as an output parameter. The other parameters described the fired product quality: linear shrinkage, bulk density, water absorption, compressive and bending strength. The main goal was to find the relationships and the main influences between raw material properties, process parameters, and the quality of the obtained products and mixtures, by using mathematical tools. Statistical and mathematical analyses were applied for prediction of final product quality. Developed artificial neural network empirical models (ANNs) give a reasonable fit to experimental data and successfully predict the most of the observed output variables, showing the good prediction capabilities (coefficient of determination varied between 0.714 and 0.998). Sensitivity analysis showed that, among all the studied parameters concerning raw materials and process parameters, the dominant influence belonged to loss on ignition.     

Sensitivity analysis of mathematical models for final product properties: Link to DTG curve

Compressive strength and water absorption of fired heavy clay products varies with firing temperatures, but not entirely according to linear function, as it is mostly reported in literature. Also, differential thermo-gravimetric curve shows many turnovers in all the samples tested, within observed temperature range (820–920 °C). The aim of this research was to find a cause for such behaviour. Except derivative weight (DW), compressive strength (CS) and water absorption (WA) are chosen as outputs that represent properties of the fired samples. These parameters can be calculated using second order polynomial models (SOPs), on the basis of content of major oxides and firing temperature, as shown in our previous research. Sensitivity analysis was used as the effective approach in testing changes observed in the SOP outputs, due to the variation of content of major oxides for +1% or −1% of their nominal value. This study reveals in more detail the most significant influence of inputs (SiO₂, Al₂O₃, Fe₂O₃ and CaO content) over the outputs (DW, CS and WA) in every observed firing temperature. Addition or lowering of content of major oxides can both increase and decrease all the observed outputs, as revealed using sensitivity analysis.