Optimal design of a class of symmetric plane frameworks of least weight

The aim of the paper is to place the recent results on the Michell-like problem of transmitting two vertical forces to two fixed hinge supports in the context of C. Maxwell’s result and to provide answers to the remarks by Vázquez Espií and Cervera Bravo (Struct Multidisc Optim, 2011) published in their Discussion Paper: On the solution of the three forces problem and its application in optimal designing of a class of symmetric plane frameworks of least weight. Discussion on the Michell class concept.     

Single- and Triaxis Piezoelectric-Bimorph Accelerometers

This paper describes the novel single- and triaxis piezoelectric-bimorph accelerometers that are built on parylene beams with ZnO films. The unamplified sensitivity and the minimum detectable signal of the fabricated single-axis accelerometer are measured to be 7.0 mV/g and 0.01 g, respectively, over a frequency range from 60 Hz to subhertz. The linearity of the sensitivity as a function of acceleration is measured to be 0.9% in the full scale. A highly symmetric quad-beam bimorph structure with a single proof mass is used for triaxis acceleration sensing and is demonstrated to produce high sensitivity, low cross-axial sensitivity, and good linearity, all in a compact size. The unamplified sensitivities of the X-, Y-, and Z-axis electrodes (of the triaxis accelerometer) in response to the accelerations in X-, Y-, and Z-axes are 0.93, 1.13, and 0.88 mV/g, respectively. The worst-case minimum detectable signal of the triaxis accelerometer is measured to be 0.04 g over a bandwidth ranging from subhertz to 100 Hz. The cross-axial sensitivity among the X-, Y-, and Z-axis electrodes is less than 15% in the triaxis accelerometer. The theoretical analyses of the charge sensitivities and resonant frequencies along with the effects of residual stress on the charge sensitivities are presented for both the single- and triaxis accelerometers.     

Content of anthocyanins and glycoalkaloids in blue‐fleshed potatoes and changes in the content of α‐solanine and α‐chaconine during manufacture of fried and dried products

In the last ten or so years, potatoes with purple or blue‐flesh and derivative products, for example chips, have appeared on the European markets. The interest in this raw material and these products is increasing among both producers and consumers searching for novel and attractive choices. The anthocyanin content of the analysed potato varieties differed; a higher content of these pigments was determined in Blaue Elise var. potatoes. In blue‐flesh varieties, the prevailing anthocyanins were acylated glycosides: petunidin and malvidin. The production process of French fries, chips and puree caused a decrease in the content of glycoalkaloids in semi‐products and finished products, compared to the raw material. The greatest losses of α‐chaconine and α‐solanine were observed after tuber peeling (ca. 70%) and after frying (ca. 90%). French fries contained 3%, chips 16% and puree 17% of the initial amount of total glycoalkaloids. The losses of α‐chaconine and α‐solanine in the analysed semi‐products and finished products were at the same level, regardless of the processing technology applied.     

In vitro release of α-tocopherol from emulsion-loaded β-lactoglobulin gels

Cold-set oil-loaded protein gels based on an emulsifying step followed by Ca²⁺-induced gelation of pre-denatured β-lactoglobulin (β-LG) have been recently developed. In vitro release and stability of a fat-soluble compound (α-tocopherol) therein were investigated in this work. Release of α-tocopherol was found to be controlled mainly by matrix erosion due to protein degradation. Compound release and matrix erosion were almost complete after incubation under gastric or intestinal conditions for 6.5 h. However, both processes were basically inhibited upon changing the dissolution medium from the gastric to the intestinal type, possibly due to β-LG partial hydrolysis products with greater emulsifying capacity anchoring to the surface of gel oil droplets. The stability of released α-tocopherol was apparently improved by binding to protein and/or hydrolysis products thereof.     

Mecanique de la rupture appliquee au beton hydraulique

Test data from the fracturing of large specimens of traditional unreinforced aggregate concrete of the double cantilever beam (DCB) type have demonstrated the existence of an extensive damage length forward of the notch root (determined by the single-dimensional acoustic-emission location technique).It is observed that the energy necessary for fracture increases as the crack propagates. This situation is characterized by a curve “R” (fracture energy as a function of crack propagation). The stationary value of the fracture energy can be much greater than the crack initiation value at the notch root.     

Exact truss topology optimization: allowance for support costs and different permissible stresses in tension and compression—extensions of a classical solution by Michell

The aim of this paper is twofold. It introduces a theory of Michell trusses taking support (reaction) costs into consideration, which is illustrated with a modified version of Michell’s best known example. Then eight other variations on this example are presented, with (i) equal or unequal permissible stresses in tension and compression, (ii) the structural domain consisting of a half-plane or a full plane, and (iii) the supports being two pins, or a pin and a roller. Previously noted shortcomings of Michell’s theory are highlighted and several fundamental properties of non-selfadjoint topology optimization problems discussed. The analytical solutions are verified to a high degree of accuracy by numerical results.     

Synthesis of tailor‐made nanoporous polyaniline derived with PVA/alkaline metal system for metal complexation

Nanoporous polyanilines (PANIs) have attracted attention due to well‐defined molecular structures and chemical versatility, which also complicate the mechanisms of interaction between metal ions and PANI. To further understand the complexation with metal ions, tailor‐made nanoporous PANIs were synthesized with self‐stabilized dispersion polymerization (SSDP) using the poly(vinyl alcohol) (PVA) and various alkaline metals for suitable target metal complexation. The effective complexation results for the removal of Cr ions were obtained by the nanoporous PANI derived from a PVA/Li system. The synthesized tailor‐made PANI‐emeraldine base (EB) was easily oxidized by a Cr(VI) oxidant resulting in an pernigraniline form with a rigid polymer template and effective metal ion binding sites, and then the reduced form of Cr(III) can be complexed with the resulting PANI. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Sorptive removal and recovery of nickel(II) from an actual effluent of electroplating industry: Comparison between <Emphasis Type=Italic>Escherichia coli</Emphasis> biosorbent and Amberlite ion exchange resin

The removal and recovery of nickel(II) from wastewater of an electroplating factory was investigated using the waste Escherichia coli biomass as the biosorbent. The results were compared with those from using Amberlite IRN-150 as a commercial sorbent resin. The resin showed better performance with a q _max value of 30.48 mg/g compared to 26.45 mg/g for the biomass, as predicted by the Langmuir isotherm model. Kinetic experiments revealed that the biosorption equilibrium was attained within 15 min. In the recycling of the sorbents, the desorption of nickel(II) from Amberlite was only 50%, which is too low for the adsorption performance of the resin to be maintained at an economic level in subsequent cycles. In contrast, the biomass exhibited reasonable adsorption-desorption performance over three repeated cycles. The capability for repeated use of the sorbent over several cycles and for recovery of the metal ions is the main advantage of the waste biomass.