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151.
Vasilica Alisa Arus Saadia Nousir Radia Sennour Tze Chieh Shiao Ileana Denisa Nistor René Roy Abdelkrim Azzouz 《International Journal of Hydrogen Energy》2018,43(16):7964-7972
The effect of acid activation on bentonite affinity toward carbon dioxide (CO2) and hydrogen (H2) was investigated at ambient conditions. Characterization through X-ray diffraction and fluorescence, thermal gravimetric analysis, nitrogen adsorption-desorption isotherms, Fourier Transform Infrared spectroscopy and differential scanning calorimetry allowed correlating newly induced textural and structural features with adsorptive properties. Optimum acid treatment improved the specific surface area and porosity. The resulting decrease in dehydration temperature indicates decay in hydrophilic character. The affinity improvement towards hydrogen was due to Brønsted acidity suppression and surface basicity attenuation, which are essential requirements for adsorption on aluminosilicates (AS) via weak Lewis Acid-Base interactions, but excessive acid attack was detrimental. Low Si/Al surfaces should be suitable for CO2 capture, while moderately acid-treated clays should be interesting candidates as hydrogen adsorbents. This allows envisaging promising prospects for low-cost AS-based materials intended for selective CO2-free capture and storage of hydrogen without energy and safety constraints. 相似文献
152.
153.
Effects of High Intensity Pulsed Electric Fields or Thermal Treatments and Refrigerated Storage on Antioxidant Compounds of Fruit Juice‐Milk Beverages. Part II: Carotenoids 下载免费PDF全文
154.
Mariana Altenhofen da Silva Beatriz Thie Iamanaka Marta Hiromi Taniwaki Theo Guenter Kieckbusch 《Packaging Technology and Science》2013,26(8):479-492
The antimicrobial potential of alginate films (AFs) and alginate/chitosan composite films with two different mass proportions of the biopolymers, 82.5:17.5 (CF1) and 65:35 (CF2), containing potassium sorbate (KS) or natamycin was evaluated. At the practical limit of KS addition (0.17 g KS per gram of alginate) for pure AFs, no inhibition zones were observed against Debaromyces hansenii, Penicillium commune and Penicillium roqueforti by the agar diffusion test. Above this concentration, films became opaque, brittle and showed a whitish precipitate over their surface, making them not suitable for use. However, alginate and alginate/chitosan composite films containing natamycin were able to inhibit the growth of the three microorganisms listed above. Natamycin was effective at concentrations as low as 0.005 g per gram of biopolymer for AF and 0.01 g per gram of biopolymer for both composite films, alginate/chitosan 65:35 (CF1) and alginate/chitosan 82.5:17.5 (CF2) against all microorganisms tested. The inhibitory zone diameter increased as concentration of natamycin increased. Active films containing 0.04 g natamycin per gram of biopolymer obtained in the present study exhibited suitable functional attributes and showed excellent perspectives as active antimicrobial films intended for food protection applications. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
155.
Amal Hamed Alexander G. Fitzgerald Lijun Wang Mariana Gueorguieva Ritu Malik Andreas Melzer 《Materials science & engineering. C, Materials for biological applications》2013,33(3):1623-1628
The aim of this research was to investigate zinc chromium ferrite (ZnCrFeO4) nanoparticles, synthesized using the sol gel technique with nanoparticle size controlled through a two-stage annealing process. Stage one was a low temperature firing which produced low quality nanocrystals with an average size of 15 nm. This was followed by a second firing stage at high temperature which enhanced the crystal quality. The nanoparticles were then coated with a bio-compatible shell to form a stable suspension in the ferrofluid carrier. The resulting nanoparticles were found by electron microscopy, atomic force microscopy and X-ray diffraction studies to have excellent crystal quality. The average size was 8.5 nm. Preliminary cell culture studies indicated the ZnCrFeO4 nanoparticles were non-toxic. The relatively high measured value of the relaxivity r2 showed that the nanoparticle coating was effective in substantially reducing aggregation and enhancing the properties of the nanoparticles associated with contrast enhancement in MRI. 相似文献
156.
157.
Leandro da Conceição Laurent Dessemond Elisabeth Djurado Mariana M.V.M. Souza 《International Journal of Hydrogen Energy》2013
La0.7Sr0.3MnO3−δ (LSM) porous films were deposited on different ferritic stainless steels (SS) (430: Cr-16.0%; 439: Cr-16.6%; 444: Cr-17.4%) by sol–gel/dip-coating process. The structure, morphology and composition profiles of investigated assemblies were examined using X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The area specific resistance (ASR) was measured during long term oxidation in air at 800 °C for 200 h by DC measurements. ASR values lower than 10 mΩ cm2 were recorded after 200 h for LSM-coated SS439 and SS444. This is likely to be due to the high Cr content and to Nb, Ti and Mo elements used to stabilize the stainless steel against oxidation. This paper shows that LSM coatings provide an enhanced stability of the alloy at high temperature and the formation of an interfacial Cr–Mn spinel layer hinders the oxide scale growth. 相似文献
158.
Valerian Dragutan Ileana Dragutan Helmut Fischer 《Journal of Inorganic and Organometallic Polymers and Materials》2008,18(1):18-31
Synthesis of a broad range of diverse polymers containing main group metals by the new ROMP approach starting from metal-functionalized
cyclic monomers and taking advantage of both classical and well-defined W-, Mo- and Ru-based metathesis catalytic systems
is critically surveyed. Emphasis is laid upon Si-containing ring-opening metathesis polymers, popular due to the easy accessibility
of the corresponding monomers and the valuable properties of the obtained polymers. Also highlighted is the production of
modern advanced materials based on metal-containing polymers as well as some of their multifarious applications. Future opportunities
for this field are finally outlined. 相似文献
159.
ABSTRACT: High aspect ratio Ni nanowires (NWs) and nanotubes (NTs) were electrodeposited inside ordered arrays of self-assembled pores (approximately 50 nm in diameter and approximately 50 um in length) in anodic alumina templates by a potentiostatic method. The current transients monitored during each process allowed us to distinguish between NW and NT formation. The depositions were long enough for the deposited metal to reach the top of the template and form a continuous Ni film. The overfilling process was found to occur in two steps when depositing NWs and in a single step in the case of NTs. A comparative study of the morphological, structural, and magnetic properties of the Ni NWs and NTs was performed using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometry, respectively. 相似文献
160.