Effect of amalgam type on artificial caries

KI

Precise Characterization and Multiobjective Optimization of Low Noise Amplifiers

Although practically all function blocks of the satellite navigation receivers are realized using the CMOS digital integrated circuits, it is appropriate to create a separate low noise antenna preamplifier based on a low noise pHEMT. Such an RF front end can be strongly optimized to attain a suitable tradeoff between the noise figure and transducer power gain. Further, as all the four principal navigation systems (GPS, GLONASS, Galileo, and COMPASS) work in similar frequency bands (roughly from 1.1 to 1.7 GHz), it is reasonable to create the low noise preamplifier for all of them. In the paper, a sophisticated method of the amplifier design is suggested based on multiobjective optimization. A substantial improvement of a standard optimization method is also outlined to satisfy a uniform coverage of Pareto front. Moreover, for enhancing efficiency of many times repeated solutions of large linear systems during the optimization, a new modification of the Markowitz criterion is suggested compatible with fast modes of the LU factorization. Extraordinary attention was also given to the accuracy of modeling. First, an extraction of pHEMT model parameters was performed including its noise part, and several models were compared. The extraction was carried out by an original identification procedure based on a combination of metaheuristic and direct methods. Second, the equations of the passive elements (including transmission lines and T-splitters) were carefully defined using frequency dispersion of their parameters as Q, ESR, etc. Third, an optimal selection of the operating point and essential passive elements was performed using the improved optimization method. Finally, the s-parameters and noise figure of the amplifier were measured, and stability and third-order intermodulation products were also checked

Glass transition of an epoxy resin induced by temperature, pressure and chemical conversion: a configurational entropy rationale

A comparative study is reported on the dynamics of a glass-forming epoxy resin when the glass transition is approached through different paths: cooling, compression, and polymerization. In particular, the influence of temperature, pressure and chemical conversion on the dynamics has been investigated by dielectric spectroscopy. Deep similarities are found in dynamic properties. A unified reading of our experimental results for the structural relaxation time is given in the framework of the Adam-Gibbs theory. The quantitative agreement with the experimental data is remarkable, joined with physical values of the fitting parameters. In particular, the fitting function of the isothermal tau(P) data gives a well reasonable prediction for the molar thermal expansion of the neat system, and the fitting function of the isobaric-isothermal tau(C) data under step- polymerization conforms to the prediction of diverging tau at complete conversion of the system.Comment: 16 pages, 8 figures, from the talk given at the 4th International Discussion Meeting on Relaxations in Complex Systems (IDMRCS), Hersonissos, Helaklion, Crete (Greece), 17-23 June 200

Composting of urban solid waste in Lomé, Togo: Fate of some heavy metals (Ni, Cu, Zn, Pb and Cd)

Metals may constitute problems in waste management because of their multiple sources and potentially high toxicity of some constituents.  Processes of composting do not always guarantee acceptable quality of the compost in terms of hazardous metals. The aim of this article is to assess the balance of some heavy metals during the composting of different categories of urban waste. The fraction of the super fines, i.e. with a particle size of less than 10 mm, contributes 30 to 56% of the total, average contents of metals in  compost. Sorting of waste into various fractions such as plastics, hazardous materials, glass, miscellaneous combustible material, metals, and super fines lowers the metal contents in finished compost by about 80%. The remaining 20% can be washed during the fermentation of windrows or, still better, can be reduced by chemical complex formation in the compost as shown by the leaching adequate test.Keywords: Heavy metals, composting, leaching test

Microtiter plate assay for phosphate using a europium–tetracycline complex as a sensitive luminescent probe

A new luminescent europium probe is presented for the determination of phosphate (P) in microtiter plate format. The assay is based on the quenching of the luminescence of the europium–tetracycline (EuTc) 1:1 complex by phosphate using a reagent concentration of 20.8 μmol/L. The probe is excited at 400 nm and displays a large Stokes’ shift of 210 nm. The emission maximum is located at 616 nm. The system works best at neutral pH 7 and is therefore suitable for phosphate determination in biological and biochemical systems. The linear range of the calibration plot is from 5 × 10−6 mol/L to 7.5 × 10−4 mol/L of phosphate, and the limit of detection is 3 μmol/L

Deux cas de freemartinisme chez des moutons Romanov (Ovis aries)

International audienc

Study of the properties of thermoset materials derived from epoxidized soybean oil and protein fillers

[EN] Novel bio-based thermoset formulations were prepared by using epoxidized soybean oil (ESBO), nadic methyl anhydride as a hardener and with different types of proteins as fillers. In the first part of the study, the effect of the protein-type (wheat gluten, soy protein, casein and ovalbumin) on cured ESBO materials was investigated. Thermal and mechanical properties were characterized by flexural tests, Shore D hardness, Charpy impact tests, Vicat softening temperature and heat deflection temperature. In addition, a study of the morphology of fractured surfaces by scanning electron microscopy was carried out. In general, the addition of protein-based fillers improved the mechanical and thermal properties. It was found that the highest increase of thermal and mechanical properties was achieved by ovalbumin. In the second part of the work, the effect of the total amount of ovalbumin filler was studied. Bio-based thermoset materials from ESBO and 15 wt % ovalbumin improved flexural modulus more than 150 % when compared to the unfilled material. Similar evolution was observed for other mechanical properties. Moreover, the brittleness of this composition was the minimum from the studied systems. A direct relationship between energy absorption capacity and morphologies of the failure surface was evidenced by SEM.This work is a part of the project IPT-310000-2010-037,"ECOTEXCOMP: Research and development of textile structures useful as reinforcement of composite materials with marked ecological character" funded by the "Ministerio de Ciencia e Innovacion", with an aid of 189540.20 euros, within the "Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica 2008-2011" and funded by the European Union through FEDER funds, Technology Fund 2007-2013, "Operational Programme on R+D+I for and on behalf of the companies". Also, Generalitat Valenciana ACOMP/2012/087 is acknowledged for financial support.Fombuena Borrás, V.; Sánchez Nacher, L.; Samper Madrigal, MD.; Juárez Varón, D.; Balart Gimeno, RA. (2013). Study of the properties of thermoset materials derived from epoxidized soybean oil and protein fillers. Journal of the American Oil Chemists' Society. 90(3):449-457. https://doi.org/10.1007/s11746-012-2171-2S449457903Alonso MV, Oliet M, Garcia J, Rodriguez F, Echeverria J (2006) Gelation and isoconversional kinetic analysis of lignin-phenol-formaldehyde resol resins cure. Chem Eng J 122:159–166Altuna FI, Esposito LH, Ruseckaite RA, Stefani PM (2011) Thermal and mechanical properties of anhydride-cured epoxy resins with different contents of bio-based epoxidized soybean oil. J Appl Polym Sci 120:789–798Boquillon N, Fringant C (2000) Polymer networks derived from curing of epoxidised linseed oil: influence of different catalysts and anhydride hardeners. Polymer 41:8603–8613Boquillon N, Elbez G, Schonfeld U (2004) Properties of wheat straw particleboards bonded with different types of resin. J Wood Sci 50:230–235Chakrapani S, Crivello JV (1998) Synthesis and photoinitiated cationic polymerization of epoxidized castor oil and its derivatives. J Macromol Sci-Pure Appl Chem A35:1–20Chen F, Zhang JW (2009) A new approach for morphology control of poly(butylene adipate-co-terephthalate) and soy protein blends. Polymer 50:3770–3777Cuq B, Contard N, Guilbert S (1998) Proteins as agricultural polymers for packaging production. Am Assoc Cereal Chem 75:1–9Czub P (2006) Application of modified natural oils as reactive diluents for epoxy resins. Macromol Symp 242:60–64DdS Martini, Braga BA, Samios D (2009) On the curing of linseed oil epoxidized methyl esters with different cyclic dicarboxylic anhydrides. Polymer 50:2919–2925Dogan E, Kuesefoglu S (2008) Synthesis and in situ foaming of biodegradable malonic acid ESO polymers. J Appl Polym Sci 110:1129–1135Espinosa-Perez J, Wiesenborn DP, Tostenson K, Ulven CA, Tatlari M (2007) Preparation and partial characterization of canola-based epoxy resins for bio-based plastic composites. ASABE Annual International Meeting, 076079, Minneapolis, MNJin H, Zhang L, Chen F (2003) Effects of lignin as a filler on properties of soy protein plastics. I Lignosulfonate. J Appl Polym Sci 88:3284–3290Liu ZS, Erhan SZ, Calvert PD (2007) Solid freeform fabrication of epoxidized soybean oil/epoxy composite with bis or polyalkyleneamine curing agents. Compos Part A Appl Sci Manuf 38:87–93Matejka L, Lovy J, Pokorny S, Bouchal K, Dusek K (1983) Curing epoxy-resins with anhydrides—model reactions and reaction-mechanism. J Polym Sci Part A Polym Chem 21:2873–2885Miyagawa H, Mohanty AK, Drzal LT, Misra M (2005) Nanocomposites from bio-based epoxy and single-wall carbon nanotubes: synthesis, and mechanical and thermo-physical properties evaluation. Nanotechnology 16:118–124Mohamed A, Finkenstadt VL, Gordon SH, Palmquist DE (2010) Thermal and mechanical properties of compression-molded pMDI-reinforced PCL/gluten composites. J Appl Polym Sci 118:2778–2790Montero de Espinosa L, Ronda JC, Galià M, Cádiz V (2008) A new enone-containing triglyceride derivative as precursor of thermosets from renewable resources. J Polym Sci Part A Polym Chem 46:6843–6850Park SJ, Jin FL, Lee JR (2004) Synthesis and thermal properties of epoxidized vegetable oil. Macromol Rapid Commun 25:724–727Pfister DP, Baker RJ, Henna HP, Lu Y, Larock CR (2008) Preparation and properties of tung oil-based composites using spent germ as a natural filler. J Appl Polym Sci 108:3618–3625Reiznautt QB, Garcia ITS, Samios D (2009) Oligoesters and polyesters produced by the curing of sunflower oil epoxidized biodiesel with cis-cyclohexane dicarboxylic anhydride: synthesis and characterization. Mater Sci Eng C Mater Biol Appl 29:2302–2311Rüsch Gen Klaas M, Warwel S (1999) Complete and partial epoxidation of plant oils by lipase-catalyzed perhydrolysis. Ind Crops Prod 9:125–132Sailaja RRN, Girija BG, Madras G, Balasubramanian N (2008) Effect of compatibilization on mechanical and thermal properties of polypropylene—soy flour composites. J Mater Sci 43:64–67Samper MD, Fombuena V, Boronat T, García-Sanoguera D, Balart R (2012) Thermal and mechanical characterization of epoxy resins (ELO and ESO) cured with anhydrides. J Am Oil Chem Soc 89(8):1521–1528Sharma S (2008) Fabrication and characterization of polymer blends and composites derived from biopolymers. Philosophy Materials Science and Engineering. Graduate School of Clemson University, ClemsonSharma BK, Liu Z, Adhvaryu A, Erhan SZ (2008) One-pot synthesis of chemically modified vegetable oils. J Agric Food Chem 56:3049–3056Sue HJ, Wang S, Jane J (1997) Morphology and mechanical behaviour of engineering soy plastics. J Polym 38:5035Wang S, Sue HJ, Jane J (1996) Effects of polyhydric alcohols on the mechanical properties of soy protein plastics. J Macromol Sci Pure Appl Chem A33:557–569Wazzan AA, Al-Turaif HA, Abdelkader AF (2006) Influence of submicron TiO2 particles on the mechanical properties and fracture characteristics of cured epoxy resin. Polym Plastics Technol Eng 45:1155–116

Revisiting consistency with random utility maximisation: theory and implications for practical work

While the paradigm of utility maximisation has formed the basis of the majority of applications in discrete choice modelling for over 40 years, its core assumptions have been questioned by work in both behavioural economics and mathematical psychology as well as more recently by developments in the RUM-oriented choice modelling community. This paper reviews the basic properties with a view to explaining the historical pre-eminence of utility maximisation and addresses the question of what departures from the paradigm may be necessary or wise in order to accommodate richer behavioural patterns. We find that many, though not all, of the behavioural traits discussed in the literature can be approximated sufficiently closely by a random utility framework, allowing analysts to retain the many advantages that such an approach possesses