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MJ M (mj + m)
Selected AbstractsMagnetic Field-Induced Phase Transformation in NiMnCoIn Magnetic Shape-Memory Alloys,A New Actuation Mechanism with Large Work OutputADVANCED FUNCTIONAL MATERIALS, Issue 7 2009Haluk E. Karaca Abstract Magnetic shape memory alloys (MSMAs) have recently been developed into a new class of functional materials that are capable of magnetic-field-induced actuation, mechanical sensing, magnetic refrigeration, and energy harvesting. In the present work, the magnetic &!hyphen;field-induced martensitic phase transformation (FIPT) in Ni45Mn36.5Co5In13.5 MSMA single crystals is characterized as a new actuation mechanism with potential to result in ultra-high actuation work outputs. The effects of the applied magnetic field on the transformation temperatures, magnetization, and superelastic response are investigated. The magnetic work output of NiMnCoIn alloys is determined to be more than 1,MJ m,3 per Tesla, which is one order of magnitude higher than that of the most well-known MSMAs, i.e., NiMnGa alloys. In addition, the work output of NiMnCoIn alloys is orientation independent, potentially surpassing the need for single crystals, and not limited by a saturation magnetic field, as opposed to NiMnGa MSMAs. Experimental and theoretical transformation strains and magnetostress levels are determined as a function of crystal orientation. It is found that [111]-oriented crystals can demonstrate a magnetostress level of 140,MPa T,1 with 1.2% axial strain under compression. These field-induced stress and strain levels are significantly higher than those from existing piezoelectric and magnetostrictive actuators. A thermodynamical framework is introduced to comprehend the magnetic energy contributions during FIPT. The present work reveals that the magnetic FIPT mechanism is promising for magnetic actuation applications and provides new opportunities for applications requiring high actuation work-outputs with relatively large actuation frequencies. One potential issue is the requirement for relatively high critical magnetic fields and field intervals (1.5,3,T) for the onset of FIPT and for reversible FIPT, respectively. [source] UV and global solar radiation in ,ód,, Central PolandINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 1 2010Agnieszka Podstawczy Abstract With the overall aim of quantifying urban atmospheric effects on different parts of the solar spectrum, a multi year analysis of data collected at ,ód, was undertaken. UV (290,400 nm) and global solar radiation measured by means of a Kipp and Zonen CUV3 radiometer and a Kipp and Zonen CM11 pyranometer in the center of ,ód, between 1997 and 2001 are analysed. The mean annual sum of global and UV solar radiation equaled 3710.8 MJ m,2 and 154.1 MJ m,2, respectively. The minimum monthly total of solar energy occurred in December (48.7 M Jm,2,global; 2.1 MJ m,2,UV); however, the maximum monthly total occurred atypically in May (620.9 MJ m,2,global; 25.3 MJ m,2,UV). UV clearness index (Kuv) is approximately half of the clearness index of the global solar radiation, indicating greater attenuation of that part of the spectrum (Kuv 0.14 in December to 0.26 in May). A linear regression model was fitted to the daily values of UV and global (g) solar irradiation (Duv = a + Dgb). The slope coefficient b and the coefficient of determination equal 0.039 and 0.98, respectively. Cloudiness exerts an important control on the solar radiation flux at the ground level and for the relation between UV and global solar radiation. The convective clouds caused an increase of global and UV solar irradiance by about 10,20% compared to clear days, the enhancement resulting from reflections. On clear days, UV comprises 3.3,4% of global solar irradiance (10-min values) on average, while during cloudy weather it increases to 8%. The results presented have implications for understanding the radiative transfer of UV and global solar radiation in the atmosphere over an urban area and the influence of clouds on transmission of solar radiation flux. Copyright © 2009 Royal Meteorological Society [source] A Calibrated, High-Resolution GOES Satellite Solar Insolation Product for a Climatology of Florida Evapotranspiration,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 6 2009Simon J. Paech Paech, Simon J., John R. Mecikalski, David M. Sumner, Chandra S. Pathak, Quinlong Wu, Shafiqul Islam, and Taiye Sangoyomi, 2009. A Calibrated, High-Resolution GOES Satellite Solar Insolation Product for a Climatology of Florida Evapotranspiration. Journal of the American Water Resources Association (JAWRA) 45(6):1328-1342. Abstract:, Estimates of incoming solar radiation (insolation) from Geostationary Operational Environmental Satellite observations have been produced for the state of Florida over a 10-year period (1995-2004). These insolation estimates were developed into well-calibrated half-hourly and daily integrated solar insolation fields over the state at 2 km resolution, in addition to a 2-week running minimum surface albedo product. Model results of the daily integrated insolation were compared with ground-based pyranometers, and as a result, the entire dataset was calibrated. This calibration was accomplished through a three-step process: (1) comparison with ground-based pyranometer measurements on clear (noncloudy) reference days, (2) correcting for a bias related to cloudiness, and (3) deriving a monthly bias correction factor. Precalibration results indicated good model performance, with a station-averaged model error of 2.2 MJ m,2/day (13%). Calibration reduced errors to 1.7 MJ m,2/day (10%), and also removed temporal-related, seasonal-related, and satellite sensor-related biases. The calibrated insolation dataset will subsequently be used by state of Florida Water Management Districts to produce statewide, 2-km resolution maps of estimated daily reference and potential evapotranspiration for water management-related activities. [source] Hydrophobic surface properties of fluoropolyetherimide blends for pervaporation membranesPOLYMER INTERNATIONAL, Issue 12 2003M Larhrafi Abstract The well-known polyetherimide (ULTEM 1000) is obtained by step-reaction of bisphenol. A diphthalic anhydride (BAPA) with m-phenylene diamine and newly related fluorinated poly etherimides synthesized from BAPA and 2,3-bis(2,2,3,3,4,4,5,5,5-nonafluoropentyl)butan-1,4 diamine (NFD) led to compatible blends over the entire range of composition. Miscible one-phase blends have been suggested by a good correlation of Tgversus NFD monomer unit weight fraction (w) (Fox and Couchman equations) and a regular morphology by scanning electron microscopy. Surface energy of blend films fell from 45.3 to 27.4 mJ m,2 for w , 0.1 corresponding to a NFD molar fraction y , 0.06. Cast-evaporated films from fluorinated copolyetherimides and blends with y < 0.15 were ductile and gave conveniently hydrophobic non-porous membranes that withstood the experimental conditions of pervaporation tests. Copyright © 2003 Society of Chemical Industry [source] | ||||||||||