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71.
Nucleation and Crystallization of New Glasses from Fly Ash Originating from Thermal Power Plants 总被引:1,自引:0,他引:1
Luisa Barbieri Isabella Lancellotti Tiziano Manfredini Gian Carlo Pellacani Jesus Ma. Rincòn Maximina Romero 《Journal of the American Ceramic Society》2001,84(8):1851-1858
The nucleation and crystallization kinetics of new glasses obtained by melting mixtures of a Spanish carbon fly ash with glass cullet and dolomite slag at 1500°C has been evaluated by a calculation method. These glasses, whose microstructure was examined by TEM carbon replica, were susceptible to controlled crystallization in the 800°–1100°C range. The resulting glass-ceramics developed acicular and branched wollastonite crystals or a network of dendritic pyroxene mixed with anorthite feldspar (SEM and EDX analysis). The time–temperature–transformation curves (processing of the XRD data) showed the crystallization kinetics and the critical cooling rate to be in the 12°–42°C/min range. 相似文献
72.
73.
In this paper we have represented the economic, environmental and territorial transformation of Metaponto district (southern Italy) generated by the land reform since 1950. The coastal area, once inhospitable and unproductive, through land reform has become a point of development for the entire Basilicata Region. The intensive model of economic development applied to agriculture and tourism today represents the main critical points of high environmental impact. In particular, the great human pressure exerted by economic activities has led to an insufficient capacity of water purification systems in the area and such criticism is amplified in the summer mainly for seaside tourism. In this study we have measured the environmental load exerted on the territory and we have estimated the human pressure on the district in the year 2030 and made proposals for amendments to current patterns of development in the agricultural and tourist sectors. 相似文献
74.
75.
Thermal Poling of Soda‐Lime Silica Glass with Nonblocking Electrodes—Part 1: Effects of Sodium Ion Migration and Water Ingress on Glass Surface Structure
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Jiawei Luo Hongtu He Nikolas J. Podraza Linmao Qian Carlo G. Pantano Seong H. Kim 《Journal of the American Ceramic Society》2016,99(4):1221-1230
It is generally well known that not only the sodium itself, but also the non‐bridging oxygen (NBO) sites associated with sodium ions are largely responsible for the surface reactivity of soda‐lime‐silica (SLS) glass. Thermal poling can modify the distribution of sodium in the subsurface region. In this work, a commercial SLS float glass was thermally poled using nonblocking electrodes in air. The Na+?depleted anode surface and the Na+?gradient cathode surface were characterized using a variety of methods to find the compositional, structural and morphological effects of thermal poling. Of particular significance is the use of nondestructive vibrational spectroscopy methods, which can lead to new and improved understanding of water interactions with sodium and its sites in the glass. It was found that during thermal poling, the Na+?depleted glass network on the anode side undergoes condensation reactions of NBO sites accompanied by the increase in concentrations of silanol (SiOH) groups and molecular water species. In contrast, silanol and water species do not increase and the silicate network change is negligible in the Na+?gradient cathode side. Vibrational sum frequency generation (SFG) spectroscopy analysis revealed the difference in distributions of hydrous species in the Na+?depleted and Na+?gradient surfaces. The structural information of the thermally‐poled surfaces provides critical insights needed to understand the mechanical and mechanochemical properties of the Na+?concentration modified SLS glass surfaces reported in the Part 2 companion paper. 相似文献
76.
Shin‐ichi Amma Michael T. Lanagan Seong H. Kim Carlo G. Pantano 《Journal of the American Ceramic Society》2016,99(4):1239-1247
The effect of alkaline‐earth ions on Na transport in aluminosilicate glasses was studied by measuring ionic conductivity for a systematic compositional series of Na2O–RO–Al2O3–SiO2 glasses (R=Mg, Ca, Sr, Ba). The Na transport in aluminosilicate glass could be affected by compositional changes in aluminum coordination and nonbridging oxygen as well as physical properties such as dielectric constant, shear modulus, and ionic packing factor. Through careful experimental designs and measurements, the main determinants among these parameters were identified. 27Al MAS‐NMR indicated that all aluminum species contained in these glasses are four‐coordinated. The activation energy for ion conductivity decreased with increasing aluminum content and decreasing ionic radii of the alkaline‐earth ion in the region where [Al] < [Na]. When the aluminum content exceeded the sodium content ([Al] > [Na]), the composition dependence of the activation energy depended on the specific alkaline earth. These results are explained based on variations in free volume and dielectric constant caused by structural changes around the AlO4 charge compensation sites. These structure changes occur in response to the smaller size and higher field strength of the alkaline‐earth ions, and are most prevalent in the compositions which require bridging of two AlO4 sites by the alkaline‐earth ion for charge compensation. 相似文献
77.
Cristina Cornaro Simona Bartocci Davide Musella Cecilia Strati Alessandro Lanuti Simone Mastroianni Stefano Penna Andrea Guidobaldi Fabrizio Giordano Eleonora Petrolati Thomas M. Brown Andrea Reale Aldo Di Carlo 《Progress in Photovoltaics: Research and Applications》2015,23(2):215-225
New generation photovoltaic (PV) devices such as polymer and dye sensitized solar cells (DSC) have now reached a more mature stage of development, and among their various applications, building integrated PVs seems to have the most promising future, especially for DSC devices. This new generation technology has attracted an increasing interest because of its low cost due to the use of cheap printable materials and simple manufacturing techniques, easy production, and relatively high efficiency. As for the more consolidated PV technologies, DSCs need to be tested in real operating conditions and their performance compared with other PV technologies to put into evidence the real potential. This work presents the results of a 3 months outdoor monitoring activity performed on a DSC mini‐panel made by the Dyepower Consortium, positioned on a south oriented vertical plane together with a double junction amorphous silicon (a‐Si) device and a multi‐crystalline silicon (m‐Si) device at the ESTER station of the University of Rome Tor Vergata. Good performance of the DSC mini‐panel has been observed for this particular configuration, where the DSC energy production compares favorably with that of a‐Si and m‐Si especially at high solar angles of incidence confirming the suitability of this technology for the integration into building facades. This assumption is confirmed by the energy produced per nominal watt‐peak for the duration of the measurement campaign by the DSC that is 12% higher than that by a‐Si and only 3% lower than that by m‐Si for these operating conditions. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
78.
Mathematical modeling of the partial hydrogenation of vegetable oil in a monolithic stirrer reactor
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Diego E. Boldrini Daniel E. Damiani Gabriela M. Tonetto 《American Institute of Chemical Engineers》2014,60(10):3524-3533
Experimental and theoretical studies on the partial hydrogenation of vegetable oil in a monolithic stirrer reactor are reported. A complete mathematical model of the reactor was developed, including hydrogenation and isomerization kinetics, catalyst deactivation, external gas–liquid and liquid–solid as well as internal mass transfer. The experimental studies were carried out in a Pd/Al2O3/Al monolithic stirrer reactor, at a wide range of temperatures (353–373 K), pressures (414–552 kPa), and catalyst loadings (0.00084–0.00527 kgPd,exp m?3). Based on this model, simulated data can be used to evaluate the catalyst (Pd/Al2O3/Al) and the hydrogenation process in consecutive catalytic tests under different operating conditions. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3524–3533, 2014 相似文献
79.
Pullulan‐based films and coatings for food packaging: Present applications,emerging opportunities,and future challenges
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Stefano Farris Ilke Uysal Unalan Laura Introzzi José Maria Fuentes‐Alventosa Carlo A. Cozzolino 《应用聚合物科学杂志》2014,131(13)
Societal and industrial demands for lower environmental impact, cost effectiveness, and high‐performance goods and services are increasingly impacting the choice of technologies which are developed and deployed in consumer products. Like many other sectors, food packaging is moving to new technologies; the use of biopolymers is one of the most promising strategies toward an optimized use of traditional packaging materials (e.g., oil‐based plastics) without impairing the goal of extending shelf life. Among other food packaging materials, pullulan is attracting much attention due to its unique features. The goal of this review is to provide an overview of current and emerging applications of pullulan within the food packaging sector. In particular, the functional properties of interest for the food packaging industry will be discussed in light of the physicochemical attributes of this exopolysaccharide. Future challenges that may dictate the successful penetration of pullulan in the food packaging market are also outlined. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40539. 相似文献
80.
The results of thermally stimulated discharging currents and isothermal direct currents measurements, performed on crosslinked polyethylene cable models aged under different thermal and electrothermal stresses, are presented and discussed. It is shown that aging affects the low-frequency behavior of the polymer. The changes observed in the relaxation processes are related to those of other properties, e.g., density, melting enthalpy, electric strength, electrical conductivity, and microstructure, as well as to the degradation phenomena caused in the insulation by the applied stresses. The proposed techniques, therefore, prove to be an effective diagnostic tool for investigating the aging of polymeric insulating materials. © 1996 John Wiley & Sons, Inc. 相似文献