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  • Open Access

    ARTICLE

    Permissible Wind Conditions for Optimal Dynamic Soaring with a Small Unmanned Aerial Vehicle

    Liu Duo-Neng1,2, Hou Zhong-Xi1, Guo Zheng1, Yang Xi-Xiang1, Gao Xian-Zhong1

    CMES-Computer Modeling in Engineering & Sciences, Vol.111, No.6, pp. 531-565, 2016, DOI:10.3970/cmes.2016.111.531 - 01 March 2022

    Abstract Dynamic soaring is a flight maneuver to exploit gradient wind field to extend endurance and traveling distance. Optimal trajectories for permissible wind conditions are generated for loitering dynamic soaring as well as for traveling patterns with a small unmanned aerial vehicle. The efficient direct collection approach based on the Runge-Kutta integrator is used to solve the optimization problem. The fast convergence of the optimization process leads to the potential for real-time applications. Based on the results of trajectory optimizations, the general permissible wind conditions which involve the allowable power law exponents and feasible reference wind… More >

  • Open Access

    ARTICLE

    Numerical Investigation Of Flow Dynamic In Mini- Channel: Case Of A Mini Diode Tesla

    Brahim DENNAI1*, Mohammed EL Bizani BELBOUKHARI1 , Tawfiq CHEKIFI1, Rachid KHELFAOUl1

    FDMP-Fluid Dynamics & Materials Processing, Vol.12, No.3, pp. 102-110, 2016, DOI:10.3970/fdmp.2016.012.102

    Abstract Microfluidic systems are used and exploited in various fields, as they are highly specific and developed in their use. The micro devices are used in various analyzes of medical disciplines, chemical and other fields. Our research team "MAAt" within ENERGARID laboratory is in the process of triggered several lines of research in this area, the micro-mixing, separation of micro particles, droplet production. For that, we need tools and micro devices to study the phenomena.. In this work, we present a theoretical study and numerical simulation of micro device (micro diode Tesla). A Diode Tesla is More >

  • Open Access

    ARTICLE

    Thermal Behavior of a U-shaped Channel Subject to a Convective Air Jet and Immersed in an Isothermal Medium

    Meryem NAOUM1, Mustapha EL ALAMI2

    FDMP-Fluid Dynamics & Materials Processing, Vol.12, No.2, pp. 56-68, 2016, DOI:10.3970/fdmp.2016.012.056

    Abstract A numerical study of mixed convection from a U-shaped channel is carried out. The flow is considered two dimensionnel. The inlet opening is adjusted in the right vertical part of the channel, while the outlet one is placed on the left vertical part. Navier–Stokes equations are solved using a control volume method and the SIMPLEC algorithm is considered for the treatment of pressure–velocity coupling. Special emphasis is given to detail the effect of the Reynolds and Rayleigh numbers on the heat transfer generated by mixed convection. The results are given for the parameters of control More >

  • Open Access

    ABSTRACT

  • Open Access

    ARTICLE

    Valorization of Tunisian Pomegranate Peel Tannins in Green Adhesives Formulation

    Houda Saad1,2,*, Antonio Pizzi3,4, Bertrand Charrier2, Naceur Ayed1, Karsten Rode5, Fatima Charrier - El Bouhtoury2

    Journal of Renewable Materials, Vol.3, No.1, pp. 34-43, 2015, DOI:10.7569/JRM.2014.634130

    Abstract The possible use of Tunisian pomegranate tannins in wood adhesive formulation was studied for the fi rst time. Colorimetric tests, Fourier transformed infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and matrix-assisted laser desorption/ionization time-of-fl ight (MALDI-TOF) mass spectrometry were used to examine pomegranate tannins. Analysis showed that pomegranate peels are rich in hydrolyzable tannins. The Stiasny number tests showed the low reactivity of pomegranate tannin extract to formaldehyde and thus the diffi culty of using it in wood adhesive formulation. Thermomechanical analysis (TMA) and strength analysis of pomegranate tannin/hexamine-based resin showed weak bonding properties. More >

  • Open Access

    ARTICLE

    Formaldehyde-Free Prorobitenidin/Profi setinidin Tannin/ Furanic Foams Based on Alternative Aldehydes: Glyoxal and Glutaraldehyde

    X. Li1, A. Pizzi1,2,*, X. Zhou3,*, V. Fierro4, A. Celzard4

    Journal of Renewable Materials, Vol.3, No.2, pp. 142-150, 2015, DOI:10.7569/JRM.2014.634117

    Abstract Tannin/furanic foams, typically 95% composed of materials of natural origin such as prorobinetinidin/ profi setinidin tannins and furfuryl alcohol, are potential alternatives to oil-based synthetic foams such as phenol-formaldehyde, and polyurethane foams. This article describes the development of second generation tannin/furanic foams, which are not only formaldehyde free, but also use nonvolatile, nontoxic aldehydes. Both glyoxal and glutaraldehyde were tried to substitute formaldehyde in tannin/furanic foams. The physical properties of these new foams are described and discussed. It was found that glutaraldehyde can totally substitute formaldehyde during tannin/furanic foam preparation, but that glyoxal cannot. The More >

  • Open Access

    ARTICLE

    Bond Strength of Biodegradable Gelatin-Based Wood Adhesives

    D.N. Dorr, S.D. Frazier, K.M. Hess, L.S. Traeger, W.V. Srubar III*

    Journal of Renewable Materials, Vol.3, No.3, pp. 195-204, 2015, DOI:10.7569/JRM.2015.634108

    Abstract A study of the potential for gelatin-based derivatives to serve as biorenewable, biodegradable adhesives for wood and engineered wood products is presented in this article. The effect of gelatin-to-water weight percent on the mechanical, specifically ultimate breaking (bond) strength, and thermal properties was investigated using tensile testing and differential scanning calorimetry, respectively. The breaking strengths of the gelatin-based adhesives were characterized and compared to four commercially available wood adhesives. The effect of 1–5% tannin addition on the mechanical, thermal, and moisture absorption behavior of the gelatin-based adhesives was also investigated. Results show that the gelatin-based More >

  • Open Access

    ARTICLE

    Natural Dyes Extraction, Stability and Application to Dye-Sensitized Solar Cells

    Mario Alejandro Mejía Escobar*, Frankin Jaramillo*

    Journal of Renewable Materials, Vol.3, No.4, pp. 281-291, 2015, DOI:10.7569/JRM.2014.634142

    Abstract In recent years, the development of new materials has contributed markedly to improving the efficiency of dye-sensitized solar cells (DSSCs). Mesoporous semiconductors, solid electrolyte, non-conventional catalysts and synthetic dyes without ruthenium have been the focus of study. With respect to the last, lanthanides and porphyrins have presented good properties, but these elements have the same disadvantage as rutheniumbased dyes; being complicated to synthesize and very expensive. These limitations have stimulated much research in the use of natural dyes as sensitizers due to their exceptional photoelectochemical properties and low cost. Furthermore, they are regarded as renewable More >

  • Open Access

    ARTICLE

    The effects of tin (Sn) additions on the growth of spinach plants

    Müller FL1,2, LF Cyster1, LM Raitt1, J Aalbers1

    Phyton-International Journal of Experimental Botany, Vol.84, No.2, pp. 461-465, 2015, DOI:10.32604/phyton.2015.84.461

    Abstract An increase in bioavailable tin in the environment could result in bioaccumulation thereof in agricultural crops, and therefore, have adverse health consequences on humans that eat these crops. The aims of the current study were thus to assess the uptake of Sn by spinach plants, and the subsequent effects this will have on the uptake of Na, Zn, K, Ca, and Mg as well as the growth of spinach plants. Spinach plants were grown in sand culture and received tin at concentrations of 0.02, 0.2, 2 and 20 mg/L along with a nutrient solution. The More >

  • Open Access

    ARTICLE

    Arbuscular mycorrhizal fungi and their effects on growth of different cultivars of Capsicum annuum L.

    González-Mendoza D1, A García-López1, C Ceceña Duran1, O Grimaldo-Juarez1, M Aviles-Marín1, Y Pérez-Luna2, P Álvarez-Gutiérrez2

    Phyton-International Journal of Experimental Botany, Vol.84, No.2, pp. 345-350, 2015, DOI:10.32604/phyton.2015.84.345

    Abstract We studied the changes in the number of leaves, roots and height on three cultivars of Capsicum anuumm (Jalapeño, Serrano and De árbol) after inoculation with Glomus intraradices FS18 and Glomus Zac-19. Results indicated that Glomus intraradices FS18 produced greater effects on height (6.12 and 5.63 cm) and number of leaves (10.66 and 5.84) in the cultivars “Jalapeño” and “De árbol”, respectively. On the other hand, Glomus zac-19 stimulated the number of leaves and roots in “Serrano” pepper (6.17 leaves and 15.31 roots) and “Arbol” (6.52 leaves and 26.32 roots). Our results demonstrate the capacity of Glomus intraradices FS18 and Glomus Zac-19 More >

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