Relating the power of the Multiple Associative Computing (MASC) model to that of reconfigurable bus-based models

The MASC (Multiple ASsociative Computing) model is a multi-SIMD model that uses control parallelism to coordinate the interaction of data parallel threads and supports associative SIMD computing on each of its threads. There have been a wide range of algorithms developed for this model. Research on using this model in real-time system applications and building a scalable MASC architecture is currently quite active. In this paper, we present simulations between MASC and reconfigurable bus-based models, e.g., various versions of the Reconfigurable Multiple Bus Machine (RMBM). Constant time simulations of the basic RMBM by MASC and vice versa are obtained. Simulations of the segmenting RMBM, fusing RMBM, and extended RMBM by MASC in non-constant time are also discussed. By taking advantage of previously established relationships between RMBM and two other popular parallel computational models, namely, the Reconfigurable Mesh (RM) and the Parallel Random Access Machine (PRAM), we extend our simulation results to further categorize the power of the MASC model in relation to RM and PRAM.     

Enhancement of sensitivity of glucose sensors from alizarin–boronic acid adducts in aqueous micelles

The sensitivity of glucose sensors fabricated from alizarin–boronic acid adducts was improved by an assistance of surfactants. Basically, Alizarin Red S (ARS) is not a fluorescence active compound. However, the fluorescence emission can be observed when forming an adduct with 2-formylphenyl boronic acid (2-FPBA). Using displacement strategy, the fluorescence intensity of the ARS/2-FPBA adduct decreased as a linear function of the glucose concentration. A simple and sensitive method was developed by incorporating the ARS/2-FPBA adduct in the hydrophobic core of micelles. Various parameters that could possibly affect the fluorescence quenching ability including solution pH, concentration of 2-FPBA, types of surfactants and concentrations of surfactants were investigated. The optimum condition for the determination of glucose by the proposed assay was 2 mM cetyltrimethylammonium bromide (CTAB) in 0.05 M phosphate buffer pH 7.0. The fluorescence intensity of the ARS/2-FPBA adduct in the presence of CTAB was remarkably 13 times higher than that in the buffer solution. Moreover, the linear working concentration range was found to be 1.2–80 mM, and the calibration sensitivity was 14 times higher than that from the system containing only buffer solution.     

Polymerization properties of polyamide in bottom‐up prepared polyamide‐calcium carbonate composites

Polyamide/calcium carbonate composites (CaCO₃) were prepared by bottom‐up process, using a precipitated CaCO₃ with polyamide monomers followed by the polymerization of the polyamide. The composites before and after the polymerization treatment were studied by gel permeation chromatography, differential scanning calorimetry, X‐ray powder diffraction, and attenuated total reflectance—Fourier transform infrared spectroscopy. A van der Waals interaction between monomer molecules and CaCO₃ surface, which was suggested by the blue shift in IR absorption band of NH₂ and CH₂, restricted the molecular motions of monomers on the CaCO₃ surfaces to inhibit the proceeding of polymerization reactions. A resembled blue shift was also observed in the polyamide/CaCO₃ composites. Besides the hydrophilic; hydrogen bonding and ionic, interactions, the van der Waals interaction should not be ignored and had a significant effect on the polymerization reactions. POLYM. COMPOS., 35:1132–1139, 2014. © 2013 Society of Plastics Engineers     

Precipitation of pharmaceuticals using a supercritical anti‐solvent (SAS) dechnique: A preliminary study

The aims of this research were to investigate the applicability of the supercritical anti‐solvent (SAS) process on the precipitation of pharmaceuticals (andrographolide and acetaminophen). In particular, the goal of this research was to study the influence of pressure at 10 and 24 MPa on particle characteristics (morphology, crystalline structure, polymorphic form, size, size distribution, and precipitation yield), and to compare the precipitation efficiency of SAS process and evaporation process. Scanning electron microscope (SEM), X‐ray diffraction (XRD), and high performance liquid chromatography (HPLC) showed a significant change in particle size, size distribution, morphology, and precipitation yield, respectively. From an analysis of the results it was found that the crystal size of andrographolide and acetaminophen decreased with increasing pressure. The morphology of andrographolide particles changed from slice‐like to column‐like when the pressure was increased. On the other hand, the acetaminophen particles obtained were found to be monoclinic form (I) under both operating pressures. The SAS process produced small uniform shaped crystals, with a narrow size distribution, high precipitation yield and selective precipitation were also observed.     

Backside calibration chronopotentiometry: using current to perform ion measurements by zeroing the transmembrane ion flux

A recent new direction in ion-selective electrode (ISE) research utilizes a stir effect to indicate the disappearance of an ion concentration gradient across a thin ion-selective membrane. This zeroing experiment allows one to evaluate the equilibrium relationship between front and backside solutions contacting the membrane by varying the backside solution composition. This method is attractive since the absolute potential during the measurement is not required, thus avoiding standard recalibrations from the sample solution and a careful control of the reference electrode potential. We report here on a new concept to alleviate the need to continuously vary the composition of the backside solution. Instead, transmembrane ion fluxes are counterbalanced at an imposed critical current. A theoretical model illustrates the relationship between the magnitude of this critical current and the concentration of analyte and countertransporting ions and is found to correspond well with experimental results. The approach is demonstrated with lead(II)-selective membranes and protons as dominating interference ions, and the concentration of Pb(2+) was successfully measured in tap water samples. The principle was further evaluated with calcium-selective membranes and magnesium as counterdiffusing species, with good results. Advantages and limitations arising from the kinetic nature of the perturbation technique are discussed.     

Nitrogen behavior in tropical wetland rice soils

Laboratory and greenhouse pot experiments show that tropical wetland rice soils are very diverse in the inherent fertility. The mineralization of native soil nitrogen differed among the soils studied. Air-drying and oven-drying of soils resulted in a large increase in nitrogen mineralized. The main source of mineralized N was the amino acid and amino sugar fractions.N uptake by rice was well correlated with N mineralized in incubation of air-dried soil which should reflect accurately the nitrogen-supplying capacities of tropical wetland rice soils during the growing season. However, plant uptake of available soil nitrogen was also correlated with total nitrogen content of soils, and it would appear that total soil nitrogen which is simple to determine is a satisfactory index of the N supplying capacities of tropical wetland rice soils. Exclusion of problem soils like acid sulfate soils improved the correlation.     

Fabrication of Pt, Pt–Cu, and Pt–Sn nanofibers for direct ethanol protonic ceramic fuel cell application

Poly(vinyl pyrrolidone) with a M _w of 1.3 × 10⁶ g/mol (PVP) or 4 × 10⁴ g/mol (PVP_Low) was used as a polymer to fabricate PVP–Pt, PVP–Pt–Cu, and PVP_Low–Pt–Sn composite fibers by electrospinning. The effect of varying the electrospinning conditions on the fiber morphology was investigated, and the solution composition and electrospinning parameters were optimized to obtain composite fibers with a minimal bead formation. Pt, Pt–Cu, and Pt–Sn metal nanofibers were then obtained by heat treatment of the respective PVP–metal or PVP_Low–metal composite fibers at 300, 350, and 450 °C, respectively, in air for 5 h. Single cells of a direct ethanol protonic ceramic fuel cell were subsequently fabricated by applying the metal nanofibers, or a commercial Pt paste, as the anode on the surfaces of BaY_0.2Zr_0.8O_3?δ pellets and Pt paste as the cathode. The I–V polarization results showed that the metal nanofiber-based anode single cells provided higher maximum power densities than that of the Pt paste anode, with the Pt nanofiber-based anode single cell producing the highest maximum power density of 0.58 mW/cm² at 550 °C.     

Properties and antimicrobial activity of edible films incorporated with kiam wood (Cotyleobium lanceotatum) extract

The antimicrobial properties of wood extracts are well known; however their application to edible films is limited. In this study, the minimum bactericidal concentration (MBC) of kiam wood extract was established as 300 mg/L at which bacterial growth was completely inhibited. The antimicrobial properties of hydroxypropyl methylcellulose (HPMC) films containing 1-5 fold of MBC of kiam wood extract were tested against Escherichia coli O175:H7, Staphylococcus aureus and Listeria monocytogenes. The edible films containing kiam wood extract exhibited more effective impact on the growth reduction of L. monocytogenes than S. aureus and E. coli (p < 0.05). The use of kiam wood extract at 1 and 2 fold of MBC incorporated into edible HPMC films did not exhibit any antimicrobial activity. However, the inhibitory effect of edible HPMC films containing kiam wood extract was observed at 3, 4 and 5 fold of MBC. The greatest zone of inhibition was observed at 5 fold of MBC incorporated in edible HPMC films. Tensile strength and elongation at break significantly decreased with the incorporation of kiam wood extract, whereas water vapor permeability and film solubility increased. The color of edible films became darker and more reddish-yellowish as well as having a lower transparency as the level of kiam wood extract was increased. Kiam wood extract incorporated in edible film provided the films with a rougher surface than pure edible film. Our results pointed out that the incorporation of kiam wood extract as a natural antibacterial agent has potential for use in extending the shelf life of food products.