In Situ Growth of Superhydrophobic Films on Aluminum Substrate

A facile and novel method was developed to fabricate highly porous CeO2 surface on aluminum via a combination of homogeneous precipitation method and in situ growth process. After the introduction of CeO2 film, aluminum exhibited excellent superhydrophobicity with contact angle of 152.9±1.5 o and a sliding angle of 5 o. SEM image of the film showed that the resulting surface exhibits a hierarchical micro-Superscript text and nanostructure, which comprised of nanoleaves that grew perpendicular to the substrate and interleaved together to form a highly porous structure. This porous architecture, along with the low surface energy renders the aluminum superhydrophobicity.

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Synthesis and Characterization of Hexagonal Prismatic Ca10(PO4)6(OH)2 Prepared by Homogeneous Precipitation Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.391-392.1239 ◽

2011 ◽

Vol 391-392 ◽

pp. 1239-1243

Author(s):

Zhan Hui Zhang ◽

Zhi Liang Huang ◽

Jian Qiu Li ◽

Ru An Chi ◽

Yue Hua Hu ◽

...

Keyword(s):

Growth Process ◽

Crystal Morphology ◽

Precipitation Method ◽

Synthesis And Characterization ◽

Hexagonal Prism ◽

Homogeneous Precipitation ◽

X Ray Diffraction ◽

X Ray ◽

Homogeneous Precipitation Method

Hexagonal prismatic hydroxyapatite (Ca10(PO4)6(OH)2, HAP) was successfully prepared by a homogeneous precipitation method. The products were characterized by X-ray diffraction, Fourier transform infrared spectrum, and scanning electron microscope. The growth process of the hexagonal prism was surveyed in detail based on the effects of the reaction time on the phase composition and the crystal morphology.

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Luminescence Properties of Europium-Doped Yttrium Oxides Derived from Their Dodecylsulfate-Templated Mesostructure and Nanotube Forms

MRS Proceedings ◽

10.1557/proc-775-p3.2 ◽

2003 ◽

Vol 775 ◽

Cited By ~ 2

Author(s):

Tsuyoshi Kijima ◽

Kenichi Iwanaga ◽

Tomomi Hamasuna ◽

Shinji Mohri ◽

Mitsunori Yada ◽

...

Keyword(s):

Room Temperature ◽

Broad Band ◽

Concentration Quenching ◽

Precipitation Method ◽

Homogeneous Precipitation ◽

Bulk Materials ◽

Main Band ◽

Homogeneous Precipitation Method ◽

Order Of Magnitude ◽

Weak Luminescence

AbstractEuropium-doped hexagonal-mesostructured and nanotubular yttrium oxides templated by dodecylsulfate species as well as surfactant free bulk oxides were synthesized by the homogeneous precipitation method. All the as grown nanostructured or bulk materials with amorphous or poorly crystalline frameworks showed weak luminescence bands at room temperature. On calcination at 1000°C these materials were converted into highly crystalline yttrium oxides, resulting in a total increase in intensity of all the bands by one order of magnitude. In the hexagonal-mesostructured system, the main band due to the 5D0-7F2 transition for the calcined phases showed a sharp but asymmetrical multiplet splitting indicating multiple Eu sites. Concentration quenching was found at a Eu content of 3 mol% or above for these phases. In contrast, the main emission for the calcined solids in the nanotubular system occurred as poorly resolved broad band and the intensity of the main band at higher Eu content was significantly enhanced compared with those for the other two systems.

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Phase Transition and Coefficients of Thermal Expansion in Al2−xInxW3O12 (0.2 ≤ x ≤ 1)

Materials ◽

10.3390/ma14144021 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4021

Author(s):

Andrés Esteban Cerón Cerón Cortés ◽

Anja Dosen ◽

Victoria L. Blair ◽

Michel B. Johnson ◽

Mary Anne White ◽

...

Keyword(s):

Phase Transition ◽

Thermal Expansion ◽

Thermal Shock ◽

Monoclinic Phase ◽

Ceramic Materials ◽

Precipitation Method ◽

Scanning Calorimetry ◽

Orthorhombic Crystal ◽

Co Precipitation

Materials from theA2M3O12 family are known for their extensive chemical versatility while preserving the polyhedral-corner-shared orthorhombic crystal system, as well as for their consequent unusual thermal expansion, varying from negative and near-zero to slightly positive. The rarest are near-zero thermal expansion materials, which are of paramount importance in thermal shock resistance applications. Ceramic materials with chemistry Al2−xInxW3O12 (x = 0.2–1.0) were synthesized using a modified reverse-strike co-precipitation method and prepared into solid specimens using traditional ceramic sintering. The resulting materials were characterized by X-ray powder diffraction (ambient and in situ high temperatures), differential scanning calorimetry and dilatometry to delineate thermal expansion, phase transitions and crystal structures. It was found that the x = 0.2 composition had the lowest thermal expansion, 1.88 × 10−6 K−1, which was still higher than the end member Al2W3O12 for the chemical series. Furthermore, the AlInW3O12 was monoclinic phase at room temperature and transformed to the orthorhombic form at ca. 200 °C, in contrast with previous reports. Interestingly, the x = 0.2, x = 0.4 and x = 0.7 materials did not exhibit the expected orthorhombic-to-monoclinic phase transition as observed for the other compositions, and hence did not follow the expected Vegard-like relationship associated with the electronegativity rule. Overall, compositions within the Al2−xInxW3O12 family should not be considered candidates for high thermal shock applications that would require near-zero thermal expansion properties.

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Development of a novel method for the in-situ dechlorination of immovable iron elements: optimization of Cl− extraction yield through experimental design

Scientific Reports ◽

10.1038/s41598-021-90006-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Marco Veneranda ◽

Nagore Prieto-Taboada ◽

Jose Antonio Carrero ◽

Ilaria Costantini ◽

Aitor Larrañaga ◽

...

Keyword(s):

Experimental Design ◽

Optimization Design ◽

Degradation Process ◽

Extraction Yield ◽

Alkaline Solutions ◽

Iron Core ◽

Total Consumption ◽

Iron Leaching ◽

Novel Method

AbstractThe conservation of iron objects exposed to marine aerosol is threatened by the formation of akaganeite, a highly unstable Cl-bearing corrosion phase. As akaganeite formation is responsible of the exfoliation of the rust layer, chlorides trigger a cyclic alteration phenomenon that often ends with the total consumption of the iron core. To prevent this degradation process, movable iron elements (e.g. archaeometallurgical artefacts) are generally immersed in alkaline dechlorination baths. Aiming to transfer this successful method to the treatment of immovable iron objects, we propose the in-situ application of alkaline solutions through the use of highly absorbent wraps. As first step of this novel research line, the present work defines the best desalination solution to be used and optimizes its extraction yield. After literature review, a screening experimental design was performed to understand the single and synergic effects of common additives used for NaOH baths. Once the most effective variables were selected, an optimization design was carried out to determine the optimal conditions to be set during treatment. According to the experimental work here presented, the use of 0.7 M NaOH solutions applied at high temperatures (above 50 °C) is recommended. Indeed, these conditions enhance chloride extraction and iron leaching inhibition, while promoting corrosion stabilization.

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Using Sentinel-2 Images to Estimate Topography, Tidal-Stage Lags and Exposure Periods over Large Intertidal Areas

Remote Sensing ◽

10.3390/rs13020320 ◽

2021 ◽

Vol 13 (2) ◽

pp. 320

Author(s):

José P. Granadeiro ◽

João Belo ◽

Mohamed Henriques ◽

João Catalão ◽

Teresa Catry

Keyword(s):

Large Scale ◽

Exposure Period ◽

Intertidal Area ◽

Digital Elevation ◽

Geographical Bias ◽

Novel Method ◽

Tidal Stage ◽

Sentinel 2

Intertidal areas provide key ecosystem services but are declining worldwide. Digital elevation models (DEMs) are important tools to monitor the evolution of such areas. In this study, we aim at (i) estimating the intertidal topography based on an established pixel-wise algorithm, from Sentinel-2 MultiSpectral Instrument scenes, (ii) implementing a set of procedures to improve the quality of such estimation, and (iii) estimating the exposure period of the intertidal area of the Bijagós Archipelago, Guinea-Bissau. We first propose a four-parameter logistic regression to estimate intertidal topography. Afterwards, we develop a novel method to estimate tide-stage lags in the area covered by a Sentinel-2 scene to correct for geographical bias in topographic estimation resulting from differences in water height within each image. Our method searches for the minimum differences in height estimates obtained from rising and ebbing tides separately, enabling the estimation of cotidal lines. Tidal-stage differences estimated closely matched those published by official authorities. We re-estimated pixel heights from which we produced a model of intertidal exposure period. We obtained a high correlation between predicted and in-situ measurements of exposure period. We highlight the importance of remote sensing to deliver large-scale intertidal DEM and tide-stage data, with relevance for coastal safety, ecology and biodiversity conservation.

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Preparation of α-Ni(OH)2 with Flowerlike Hierarchical Architectures via Homogeneous Precipitation Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.284-286.684 ◽

2011 ◽

Vol 284-286 ◽

pp. 684-687

Author(s):

Chang Yu Li ◽

Li Li Liu ◽

Shou Xin Liu

Keyword(s):

Electron Microscopy ◽

Precipitation Method ◽

Homogeneous Precipitation ◽

X Ray ◽

Homogeneous Precipitation Method ◽

Α Phase ◽

Transmission Electron ◽

Hierarchical Architectures ◽

Flowerlike Structure ◽

Adsorption Desorption

Without using any templates or surfactants, flowerlike α-nickel hydroxide (Ni(OH)2) was successfully synthesized by homogeneous precipitation method. The prepared products were characterized by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and N2 adsorption-desorption. The prepared Ni(OH)2 is α-phase with specific surface area of 245.0 m2/g and shows flowerlike structure with 4-6 um in diameter.

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Fabrication and Evaluation of Nano-TiO2 Superhydrophobic Coating on Asphalt Pavement

Materials ◽

10.3390/ma14010211 ◽

2021 ◽

Vol 14 (1) ◽

pp. 211

Author(s):

Hongfeng Li ◽

Xiangwen Lin ◽

Hongguang Wang

Keyword(s):

Contact Angle ◽

Stearic Acid ◽

Asphalt Pavement ◽

Asphalt Mixture ◽

Waterborne Polyurethane ◽

Superhydrophobic Coating ◽

Nano Tio2 ◽

Sem Image ◽

Low Surface Energy ◽

Water Damage

In order to address water damage of asphalt pavement, reduce the occurrence of water-related potholes, deformation, and other diseases, and improve the performance and service life of the pavement, a nano-TiO2 superhydrophobic coating (PSC) on asphalt pavement was prepared from waterborne polyurethane and nano-TiO2 modified by stearic acid. FT-IR measured stearic acid successfully modified low surface energy substance on the surface of nano-TiO2. The SEM image shows that the PSC has a rough surface structure. The contact angle and rolling angle of the PSC in the contact angle test are 153.5° and 4.7°, respectively. PSC has a super-hydrophobic ability, which can improve the water stability of the asphalt mixture. Although the texture depth and pendulum value have been reduced by 2.5% and 4.4%, respectively, they all comply with the standard requirements. After the abrasion resistance test, the PSC coating still has a certain hydrophobic ability. These results surface PSC coating can effectively reduce water damage on asphalt pavement, and has considerable application value.

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