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1
Ferraz, Antonio. "DÉTECTION À HAUTE RÉSOLUTION SPATIALE DE LA DESSERTE FORESTIÈRE EN MILIEU MONTAGNEUX." Revue Française de Photogrammétrie et de Télédétection 1, no. 211-212 (December 6, 2015): 103–17. http://dx.doi.org/10.52638/rfpt.2015.549.
Повний текст джерелаАнотація:
En milieu montagneux et forestier, la localisation de la route et ses caractéristiques géométriques sont des informations cruciale pour de nombreuses applications écologiques et liées à la gestion forestière. Par ailleurs, le lidar aéroporté topographique est devenu une technique de télédétection reconnue pour la caractérisation fine de la surface terrestre : les Modèles Numériques de Terrain (MNT) en sont le produit standard.Cet article aborde le problème de la détection de routes sur de grandes surfaces (>1000 km2) dans de tels environnements. Pour cela, nous avons proposé une méthode fondée sur l’hypothèse que les routes peuvent être modélisées par des objets planaires suivant une direction privilégiée et avec de fortes variations du relief dans la direction orthogonale. La connaissance seule du MNT lidar à 1 m de résolution est suffisante dans notre processus, qui ne requiert donc pas le traitement supplémentaire des nuages de points 3D lidar ni de données à retour d’onde complète. L’intégralité de l’analyse se fait donc en deux dimensions. Tout d’abord, trois attributs morphologiques sont extraits du MNT et introduits dans une classification supervisée par Forêts Aléatoires des zones potentiellement "routes". Ensuite, un graphe est créé à partir de ce masque de focalisation afin de combler les éventuels manques et occlusions dus principalement à la végétation. En particulier, les noeuds sont sélectionnés avec un Processus Ponctuel, puis le graphe est élagué en suivant le modèle de route initial. Enfin, la largeur et la pente des routes sont estimées grâce au MNT avec une analyse orientée-objet. D’une part, on obtient une qualité de détection convaincante, tant au niveau de l’exhaustivité (>80%) que de la précision géométrique, supérieure à celle des bases de données topographiques 2D existantes. De plus, de nouvelles routes sont détectées grâce à la capacité du lidar à restituer le terrain sous le couvert végétal. Cependant, en présence d’un trop faible nombre de mesures lidar au niveau du sol, des routes peuvent ne pas être restituées. Enfin, nous montrons que notre méthode est adaptée à une analyse sur de grandes surfaces puisqu’elle permet des rendements de moins de 2 minutes par km2.
2
Zhang, Ji Fa, Dong Li Xu, and Zhi Hui Wang. "Modeling Approach for Fiber Placement Routes on Complex Surface." Applied Mechanics and Materials 686 (October 2014): 560–66. http://dx.doi.org/10.4028/www.scientific.net/amm.686.560.
Повний текст джерелаАнотація:
According to the characteristics of a curve on the surface, the correlation between the placement feasibility for fiber tow and the surface shape of a composite component, width of the fiber tows is analyzed. The placement process route under the condition of fiber tow ultimate deformation is calculated. In addition, based on fiber loading orientation in the designed placement layers, the best mechanical route is calculated. Through the given proportionality coefficient of geodesic arc radii under the constrain conditions of the mechanics and fiber tow deformability on the present route point, a simple modeling approach is proposed to obtain the actual model of the route with the goal of satisfying the best mechanical route orientation . Take the placement of a free form surface as an example to verify the approach, with the result of indicating its reasonableness.
3
Muraleetharan, Thambiah, Kunio Meguro, Takeo Adachi, Toru Hagiwara, and Sei'ichi Kagaya. "Influence of Winter Road Conditions and Signal Delay on Pedestrian Route Choice in Japan's Snowiest Metropolis." Transportation Research Record: Journal of the Transportation Research Board 1939, no. 1 (January 2005): 145–53. http://dx.doi.org/10.1177/0361198105193900117.
Повний текст джерелаАнотація:
Investigation of pedestrian route choice behavior on icy surfaces is important for the effective improvement of walkways in winter. The objective of this research was to investigate pedestrian route choice behavior in winter. Field surveys and questionnaire surveys were conducted to fulfill this objective. Video cameras were used in the field surveys to clarify the movements of pedestrians. How pedestrians chose their routes was investigated by observing their movements. According to the field survey, when the signal was green, the probability that the pedestrian would cross became extremely high, regardless of the road surface conditions. However, when the walkway surface was icy, the probability that the pedestrian would wait for a green signal decreased by a considerable value. This indicates that when the wait becomes long, the probability that the pedestrian will cross becomes low during the snowy season. A questionnaire survey was also conducted to clarify the factors affecting pedestrian route choice behavior. The questionnaire asked about different road surface conditions. The results from the survey indicate that even if part of a road section has a good surface condition, it has a strong influence on route choice behavior. It indicates that pedestrians feel uncomfortable in walking on slippery walkways and they prefer to choose bare walkways. On the basis of the data from the field survey and questionnaire survey, logit models were developed to express quantitatively the route choice behaviors of pedestrians. These models can be used to predict the probability that a pedestrian will select a route as a function of pedestrian delay at signalized intersections and the road surface conditions in winter.
4
Lu, Yun, Yi Xing Liu, Hai Peng Yu, and Qing Feng Sun. "Controlled Grown TiO2 on Cellulose Surface via a Hydrothermal Route." Advanced Materials Research 179-180 (January 2011): 1173–76. http://dx.doi.org/10.4028/www.scientific.net/amr.179-180.1173.
Повний текст джерелаАнотація:
Controlled anatase TiO2 was grown on cellulose surface using a fragile hydrothermal method in different conditions. With the analysis of FTIR spectra, the grown TiO2 was chemically attached to the cellulose surface. The morphologies and amount of grown TiO2 on cellulose surface could be controlled through the adjustment of reacting factors. From the observation of SEM images, the morphology and content of TiO2 grown on cellulose surface could be controlled under appropriate reaction conditions. Under the regulation of reactant conditions, the content ranging from 8.7%-34.2% of TiO2 could be grown on cellulose surface.
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Masi, Maurizio, Alessandro Veneroni, A. Fiorucci, Francesco La Via, Gaetano Foti, Marco Mauceri, Stefano Leone, et al. "Film Morphology and Process Conditions in Epitaxial Silicon Carbide Growth via Chlorides Route." Materials Science Forum 556-557 (September 2007): 93–96. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.93.
Повний текст джерелаАнотація:
A simplified deposition model, involving both the description of the deposition and of the film morphology was adopted to quantitatively understand the experimental trends encountered in the epitaxial silicon carbide deposition in an industrial hot wall reactor. The attention was focused on the system involving chlorinated species because its really superior performances with respect the traditional silane/hydrocarbons process. The evolution of the crystalline structure (i.e., from poly to single) and of the surface roughness can be understood by simply comparing two characteristic times, like those inherent the surface diffusion and the matter supply to the surface.
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Dodukh, Kateryna, and Anton Palchyk. "Influence of road conditions on vehicles’ fuel consumption." Automobile Roads and Road Construction, no. 109 (2021): 166–73. http://dx.doi.org/10.33744/0365-8171-2021-109-166-173.
Повний текст джерелаАнотація:
The article deals with the influence of road conditions on fuel consumption by vehicles when transporting goods and passengers, which depends on the speed of movement. The optimum fuel consumption corresponds to the optimum speed of movement which is distinctive for each type of car. Increase or decrease of the optimum speed leads to increased fuel consumption. Elevations reduce the speed and increase fuel consumption by up to 30%. Road conditions (width of roadway, condition of surface, presence of horizontal curves, longitudinal slopes, pedestrian crossings, settlements) cause a change in the speed of movement and consumption of fuel and lubricants. It is possible to take into account the road conditions by plotting the speed of movement along the route, the change in the speed occuring during the travel time and socio-economic indicators of the route. Based on this chart, fuel costs and route times are calculated. Since the cost of fuel is 50-52% of the cost of transportation of goods and passengers, the cost will be roughly 2 times higher. The cost of transportation of goods by trucks is characterized by the cost of transportation, and the transportation of passengers by the cost and time spent by passengers when traveling the route.
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Fu, Liping, Lalita Thakali, Tae J. Kwon, and Taimur Usman. "A risk-based approach to winter road surface condition classification." Canadian Journal of Civil Engineering 44, no. 3 (March 2017): 182–91. http://dx.doi.org/10.1139/cjce-2016-0215.
Повний текст джерелаАнотація:
This paper presents a risk-based approach for classifying the road surface conditions of a highway network under winter weather events. A relative risk index (RRI) is developed to capture the effect of adverse weather conditions on the collision risk of a highway in reference to the normal driving conditions. Based on this index, multiple risk factors related to adverse winter weather conditions can be considered either jointly or separately. The index can also be used to aggregate different types of road conditions observed on any given route into a single class for risk-consistent condition classification and reporting. Two example applications are shown to illustrate the advantages of the proposed approach.
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Alateyah, Abdulrahman I., Waleed H. El-Garaihy, Majed O. Alawad, Samar El Sanabary, Sally Elkatatny, Hany A. Dahish, and Hanan Kouta. "The Effect of ECAP Processing Conditions on Microstructural Evolution and Mechanical Properties of Pure Magnesium—Experimental, Mathematical Empirical and Response Surface Approach." Materials 15, no. 15 (August 2, 2022): 5312. http://dx.doi.org/10.3390/ma15155312.
Повний текст джерелаАнотація:
In this study, a quantitative evaluation approach was used to investigate how certain ECAP processing parameters affect the microstructural evolution, Vicker’s microhardness values and tensile properties of pure Mg. The ECAP processing parameters were number of passes, ECAP die channel angle and processing route type. The response surface methodology (RSM) technique was used to design 16 runs of the experiment using Stat-Ease design expert software. Billets of pure Mg were processed up to four passes of routes Bc, A and C at 225 °C. Two ECAP dies were used with internal channel angles of 90° and 120°. Experimental findings were used to establish empirical models to assess the influence of the ECAP processing parameters on grain size and mechanical properties of ECAPed billets. The established relationships were examined and validated for their adequacy and significance using ANOVA as well as several statistical criteria. Response surface plots and contour graphs were established to offer better understanding of the intended relationships. In addition, the optimum processing parameters for grain size, hardness values and tensile properties were defined. Both experimental results and the theoretical model revealed that route Bc is the most effective route in grain refining. The experimental findings showed that four passes of route Bc through the die channel angle 90° revealed a significant reduction in the grain size by 86% compared to the as-annealed counterparts. Similar to the grain size refining, four-passes processing through the ECAP die with an internal channel angle of 90° leads to improved Vicker’s microhardness values. Additionally, four passes of route Bc using the 90° die angle recorded a significant HV increase at the edge and central areas by 112% and 78%, respectively, compared to the as-annealed counterpart. On the other hand, according to the optimization findings, two passes of route Bc using a die angle of 120° resulted in the best ultimate tensile strength for pure Mg, whereas four passes of route Bc revealed the optimum ductility at fracture.
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Jeong, Soo-Hwan, Ju-Hye Ko, Jong-Bong Park, and Wanjun Park. "A Sonochemical Route to Single-Walled Carbon Nanotubes under Ambient Conditions." Journal of the American Chemical Society 126, no. 49 (December 2004): 15982–83. http://dx.doi.org/10.1021/ja0451867.
Повний текст джерела
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Dahe, Qin, Paul A. Mayewski, W. Berry Lyons, Sun Junying, and Hou Shugui. "Lead pollution in Antarctic surface snow revealed along the route of the International Trans-Antarctic Expedition." Annals of Glaciology 29 (1999): 94–98. http://dx.doi.org/10.3189/172756499781820897.
Повний текст джерелаАнотація:
AbstractThis paper reports the lead concentration and flux (where accumulation rate is available) along the route of the 1990 International Trans-Antarctic Expedition. The lead concentration in Larsen Ice Shelf and Antarctic Peninsula, the western part of the route, was 7.4 ± 4.1 pg g−1. The lead concentration in East Antarctic snow (South Pole to Mirny station) was 2 3 times higher than that in West Antarctica (Larsen Ice Shelf to South Pole). Taking into account the difference in site conditions, the difference between the above value over this area in 1989 and the value of 6.3 ±3.3 pg g−1 at a site within this area in 1980 (Wolff and Peel, 1985) is not significant. Because the relative contribution of soil dust, volcanoes and the oceans to lead concentration in Antarctica is about 0.5 pg g−1 under modern climatic conditions (Boutron and Patterson, 1987), it is believed that the lead in Antarctic surface snow is dominated by pollution input. The lead-concentration increase from west to east over the trans-Antarctic route suggests that remote Antarctica has been impacted by anthropogenic activities. The lowest lead flux (0.064 ng cn-2 a−1) was on the Antarctic Plateau, mainly reflecting the background global pollution. The mean flux of 0.273 ng cnT2 a−1 in the western part of the route (Larsen Ice Shelf to the Ellsworth Mountains) may result from the pollution input from the Southern Hemisphere. In addition to the influence of global and/or hemispheric pollution, local activities (notably the use of leaded gasolene) appear to have affected the region from Pionerskaya to Mirny.
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Baláž, Peter, Parviz Pourghahramani, Erika Dutková, Martin Fabián, Jaroslav Kováč, and Alexander Šatka. "PbS nanostructures synthesized via surfactant assisted mechanochemical route." Open Chemistry 7, no. 2 (June 1, 2009): 215–21. http://dx.doi.org/10.2478/s11532-009-0005-3.
Повний текст джерелаАнотація:
AbstractPbS nanocrystals using surfactant assisted mechanochemical route has been successfully prepared. The methods of XRD, SEM, surface area and particle size measurements were used for nanocrystals characterization. The XRD patterns confirmed the presence of galena PbS (JCPDS 5–592) whatever treatment conditions were applied. The strong observable peaks indicate the highly crystalline nature in formation of PbS nanostructures where preferential crystal growth in the (200) direction after chelating agent (EDTANa2•2H2O) addition has been observed. The mean volume weighted crystallite size 4.9 nm and 35 nm has been calculated from XRD data using Williamson-Hall method for PbS synthesized without and/or with chelating agent, respectively corresponding with surface weighted crystallites sizes of 2.9 and 18.8 nm. The sample prepared without surfactant yields the smaller crystallites and the higher microstrain compared with surfactant assisted synthesis. The obtained results illustrate a possibility to manipulate crystal morphology by combining effect of milling and surfactant application.
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Nandan, Sandeep, T. G. Deepak, Shantikumar V. Nair, and A. Sreekumaran Nair. "TiO2 nanofibers resembling ‘yellow bristle grass’ in morphology by a soft chemical transformation." Dalton Trans. 44, no. 20 (2015): 9637–45. http://dx.doi.org/10.1039/c5dt01027f.
Повний текст джерелаАнотація:
We synthesized a uniquely shaped one-dimensional (1-D) TiO2 nanostructure having the morphology of yellow bristle grass with high surface area by the titanate route under mild reaction conditions.
13
Chalmpes, Nikolaos, Iosif Tantis, Aristides Bakandritsos, Athanasios B. Bourlinos, Michael A. Karakassides, and Dimitrios Gournis. "Rapid Carbon Formation from Spontaneous Reaction of Ferrocene and Liquid Bromine at Ambient Conditions." Nanomaterials 10, no. 8 (August 9, 2020): 1564. http://dx.doi.org/10.3390/nano10081564.
Повний текст джерелаАнотація:
Herein, we present an interesting route to carbon derived from ferrocene without pyrolysis. Specifically, the direct contact of the metallocene with liquid bromine at ambient conditions released rapidly and spontaneously carbon soot, the latter containing dense spheres, nanosheets, and hollow spheres. The derived carbon carried surface C-Br bonds that permitted postfunctionalization of the solid through nucleophilic substitution. For instance, treatment with diglycolamine led to covalent attachment of the amine onto the carbon surface, thus conferring aqueous dispersability to t he solid. The dispersed solid exhibited visible photoluminescence under UV irradiation as a result of surface passivation by the amine. Hence, the present method not only allowed a rapid and spontaneous carbon formation at ambient conditions, but also surface engineering of the particles to impart new properties (e.g., photoluminescence).
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Sibomana, M. S., L. W. Ziena, S. Schmidt, and T. S. Workneh. "Influence of Transportation Conditions and Postharvest Disinfection Treatments on Microbiological Quality of Fresh Market Tomatoes (cv. Nemo-Netta) in a South African Supply Chain." Journal of Food Protection 80, no. 2 (January 27, 2017): 345–54. http://dx.doi.org/10.4315/0362-028x.jfp-16-229.
Повний текст джерелаАнотація:
ABSTRACT Postharvest microbial spoilage due to suboptimal transportation and packaging conditions is a key concern for the South African tomato industry. This study investigated the influence of washing with tap water or aqueous disinfectant solutions (chlorinated and anolyte water) on the microbiological quality of tomatoes during storage after transportation in nonrefrigerated trucks along two supply routes when packaged in crates and boxes. Route 1 was 1,093 km from field to storage site, while route 2 was 1,057 km. During transport, the temperature in the trucks fluctuated between 16 and 28°C and the relative humidity between 25 and 94% for route 1, while for route 2, the temperature was between 16 and 30°C and the relative humidity between 28 and 71%. Tomatoes at the pink maturity stage were sampled, treated, and stored for 28 days (11°C). The tomato firmness before treatment was 24.8 N (box samples) and 17.4 N (crate samples) for route 1, whereas it was 22.1 N (box samples) and 20.2 N (crate samples) for route 2. Temperature fluctuation during transportation led to water condensation on tomato surfaces. Tomatoes treated with anolyte water showed the lowest microbial surface burden during storage, with mean aerobic plate counts (APC) of 2.9 log CFU/cm2, coliform counts (CC) of 1.1 log CFU/cm2, and fungal counts (FC) of 2.3 log CFU/cm2. Overall, of the total APC recorded during storage, anolyte-treated samples contributed 9% while chlorinated water–treated samples contributed 30%. Of the total CC, anolyte samples presented 3% while chlorinated water samples made up 12%, and of the total recorded FC, anolyte samples contributed 7% while chlorinated water samples made up 22%. Scanning electron microscopy imaging showed surface cracks, which enable microbial colonization in crate-transported tomatoes. A combination of anolyte treatment and box packaging during transport resulted in the best microbiological quality during storage. The findings of this investigation provide motivation for the adoption of anolyte water as a postharvest disinfection treatment in the tomato industry.
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Eadi, S. B., and S. K. Hong. "One-Step Route to Grow ZnO Hexangular Tube Structures." International Journal of Nanoscience 18, no. 03n04 (June 2019): 1940057. http://dx.doi.org/10.1142/s0219581x1940057x.
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We present a systematic study of hexangular ZnO nanotube growth using zinc nitrate and NaOH as starting materials by varying solution concentration. ZnO nanotubes were characterized by field emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and growth mechanism was discussed. Supersaturation near ZnO surface is higher and leads to the [Formula: see text]-axis preferential growth. Low-magnification and high-resolution TEM micrographs revealed that best growth conditions for ZnO nanotube arrays were at 5[Formula: see text]mM zinc nitrate and 1[Formula: see text]mL of 1[Formula: see text]M NaOH. The growth morphology is largely determined by varying the NaOH concentration.
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Montgomery, M. T., M. E. Nicholls, T. A. Cram, and A. B. Saunders. "A Vortical Hot Tower Route to Tropical Cyclogenesis." Journal of the Atmospheric Sciences 63, no. 1 (January 1, 2006): 355–86. http://dx.doi.org/10.1175/jas3604.1.
Повний текст джерелаАнотація:
Abstract A nonhydrostatic cloud model is used to examine the thermomechanics of tropical cyclogenesis under realistic meteorological conditions. Observations motivate the focus on the problem of how a midtropospheric cyclonic vortex, a frequent by-product of mesoscale convective systems during summertime conditions over tropical oceans, may be transformed into a surface-concentrated (warm core) tropical depression. As a first step, the vortex transformation is studied in the absence of vertical wind shear or zonal flow. Within the cyclonic vorticity-rich environment of the mesoscale convective vortex (MCV) embryo, the simulations demonstrate that small-scale cumulonimbus towers possessing intense cyclonic vorticity in their cores [vortical hot towers (VHTs)] emerge as the preferred coherent structures. The VHTs acquire their vertical vorticity through a combination of tilting of MCV horizontal vorticity and stretching of MCV and VHT-generated vertical vorticity. Horizontally localized and exhibiting convective lifetimes on the order of 1 h, VHTs overcome the generally adverse effects of downdrafts by consuming convective available potential energy in their local environment, humidifying the middle and upper troposphere, and undergoing diabatic vortex merger with neighboring towers. During metamorphosis, the VHTs vortically prime the mesoscale environment and collectively mimic a quasi-steady diabatic heating rate within the MCV embryo. A quasi-balanced toroidal (transverse) circulation develops on the system scale that converges cyclonic vorticity of the initial MCV and small-scale vorticity anomalies generated by subsequent tower activity. The VHTs are found to accelerate the spinup of near-surface mean tangential winds relative to an approximate axisymmetric model that excises the VHTs. This upscale growth mechanism appears capable of generating a tropical depression vortex on time scales on the order of 1–2 days, for reasonable parameter choices. Further tests of the VHT paradigm are advocated through diagnoses of operational weather prediction models, higher resolution simulations of the current configuration, examination of disruption scenarios for incipient vortices, and a meteorological field experiment.
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Huang, Jun, Xiao Jing Lv, Mi Ouyang, Bin Hu, and Cheng Zhang. "Atmospheric Pressure Synthesis of ZnO Nanotubes by Aqueous Solution Route." Advanced Materials Research 669 (March 2013): 189–93. http://dx.doi.org/10.4028/www.scientific.net/amr.669.189.
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Single-crystalline ZnO nanotubes were fabricated via a simple aqueous solution method under low temperature and atmospheric pressure conditions. X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) equipped with the selected area electron diffraction (SAED) setup were used to analyze the crystal structure, surface morphology and inner structure of ZnO nanotubes. Photoluminescence (PL) and UV-visible absorption spectra were carried out to investigate optical properties of ZnO nanotubes. The results indicate ZnO nanotubes only exhibit sharp and strong near ultraviolet emission at 363 nm according to PL spectrum.
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He, Quan Guo, Zhao Hui Wu, and Rong Hu. "Platinum Immobilization on Iron Oxide Nanoparticles Surface under Sonication." Advanced Materials Research 183-185 (January 2011): 1989–94. http://dx.doi.org/10.4028/www.scientific.net/amr.183-185.1989.
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A facile and environment-friendly sonochemical route to fabricate well-defined Fe3O4/Pt and γ-Fe2O3/Pt composite microspheres under mild conditions has been reported. The structure and morphology of the synthetic spherical-shaped Fe3O4/Pt and γ-Fe2O3/Pt products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) with selected area electron diffraction (SAED). The results revealed that the composites were spherical with diameter in the range of 50–80 nm and had an ordered face-centered cubic (fcc) structure of platinum. These nanocomposites with platinum-coated iron oxide can be applied in a variety of areas, including medicine, photonics, new functional device assemblies and catalysis especially for fabricating some magnetic-responsive catalyst.
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Yang, Jie, Hao Chen, Haibo Niu, Josiah McNutt, and Quan He. "A Comparative Study on Thermochemical Valorization Routes for Spent Coffee Grounds." Energies 14, no. 13 (June 25, 2021): 3840. http://dx.doi.org/10.3390/en14133840.
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Extracting oil from spent coffee grounds (SCG) for biodiesel production has recently attracted much research interest. Large amounts of organic solvents are involved for oil extraction and biodiesel synthesis. Hydrothermal liquefaction (HTL) is an emerging thermochemical technology with great potential for biocrude production from a broad range of feedstocks. This study attempted to compare two SCG valorization options: route 1, oil extraction for biodiesel production followed by HTL of defatted SCG; and route 2, direct HTL of raw SCG. The microwave-assisted extraction conditions were optimized to effectively remove oil from SCG using response surface methodology. Under optimal conditions, an SCG oil yield of 8.4 wt.% could be achieved. HTL of defatted SCG generated less biocrude (18.9 wt.%) than that of raw SCG (28.1 wt.%). The biochemical compositions of resultant biocrudes were largely different from each other. The life cycle assessment was conducted on each of the SCG valorization routes and showed that the greenhouse gas emissions from direct HTL of raw SCG were only 35% of the other valorization route, suggesting that direct HTL is a favorable valorization route for SCG within this study’s scope.
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Abbott, Erik C., Alexandria Brenkmann, Craig Galbraith, Joshua Ong, Ian J. Schwerdt, Brent D. Albrecht, Tolga Tasdizen, and Luther W. McDonald IV. "Dependence of UO2 surface morphology on processing history within a single synthetic route." Radiochimica Acta 107, no. 12 (November 26, 2019): 1121–31. http://dx.doi.org/10.1515/ract-2018-3065.
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AbstractThis study aims to determine forensic signatures for processing history of UO2based on modifications in intermediate materials within the uranyl peroxide route. Uranyl peroxide was calcined to multiple intermediate U-oxides including Am-UO3, α-UO3, and α-U3O8during the production of UO2. The intermediate U-oxides were then reduced to α-UO2via hydrogen reduction under identical conditions. Powder X-ray diffractometry (p-XRD) and X-ray photoelectron spectroscopy (XPS) were used to analyze powders of the intermediate U-oxides and resulting UO2to evaluate the phase and purity of the freshly synthesized materials. All U-oxides were also analyzed via scanning electron microscopy (SEM) to determine the morphology of the freshly prepared powders. The microscopy images were subsequently analyzed using the Morphological Analysis for Materials (MAMA) version 2.1 software to quantitatively compare differences in the morphology of UO2from each intermediate U-oxide. In addition, the microscopy images were analyzed using a machine learning model which was trained based on a VGG 16 architecture. Results show no differences in the XRD or XPS spectra of the UO2produced from each intermediate. However, results from both the segmentation and machine learning proved that the morphology was quantifiably different. In addition, the morphology of UO2was very similar, if not identical, to the intermediate material from which it was prepared, thus making quantitative morphological analysis a reliable forensic signature of processing history.
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Chen, Jiali, Lianhan Huang, Liming Sun, and Xiaofan Zhu. "Desulfurization performance of MgO/ rice straw biochar adsorbent prepared by co-precipitation/calcination route." BioResources 15, no. 3 (May 5, 2020): 4738–52. http://dx.doi.org/10.15376/biores.15.3.4738-4752.
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A solid adsorbent for SO2 adsorption was prepared from magnesium salt/rice straw via co-precipitation/calcination. The effects of various preparation conditions, including the calcination temperature, the weight ratio of Mg/rice straw, magnesium salts, and amine precipitants, were investigated relative to their effects on the desulfurization performance of adsorbents. Maximum sulfur adsorption capacity (260 mg/g) was obtained with MgO/rice straw biochar adsorbent using tetraethylenepentamine (TEPA) as the precipitants, and the preparation conditions included a calcination temperature of 400 °C, a Mg/rice straw weight ratio of 1.2, and magnesium chloride hexahydrate (MgCl2·6H2O) as the magnesium source. The rice straw biochar-supported MgO sample displayed a high SO2 adsorption capacity due to its excellent textural properties, large specific surface areas, small crystallite size, numerous surface active sites of MgO nanoparticles, and introduced N-H groups. The physical and chemical properties of samples were investigated by field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET) analyses, Fourier transform infrared spectrometer (FT-IR), elemental analysis (EA), and X-ray diffraction (XRD).
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Xu, Hao, Jie Zhu, Xiong Wang, Chao Shen, Shengshen Meng, Kai Zheng, Chao Lei, and Longfeng Zhu. "Sustainable Route for Synthesizing Aluminosilicate EU-1 Zeolite." Molecules 26, no. 5 (March 8, 2021): 1462. http://dx.doi.org/10.3390/molecules26051462.
Повний текст джерелаАнотація:
Developing sustainable routes for the synthesis of zeolites is still a vital and challenging task in zeolite scientific community. One of the typical examples is sustainable synthesis of aluminosilicate EU-1 zeolite, which is not very efficient and environmental-unfriendly under hydrothermal condition due to the use of a large amount of water as solvent. Herein, we report a sustainable synthesis route for aluminosilicate EU-1 zeolite without the use of solvent for the first time. The physicochemical properties of the obtained EU-1 zeolite are characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry-differential thermal analysis (TG-DTA), N2 sorption, inductively coupled plasma (ICP) analysis, and solid nuclear magnetic resonance (NMR), which show the product has high crystallinity, uniform morphology, large BET surface area, and four-coordinated aluminum species. Moreover, the impact of synthesis conditions is investigated in detail. The sustainable synthesis of aluminosilicate EU-1 zeolite under solvent-free
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Segall, A. E. "Thermoelastic Stresses in Thick-Walled Vessels Under Thermal Transients via the Inverse Route." Journal of Pressure Vessel Technology 128, no. 4 (January 19, 2006): 599–604. http://dx.doi.org/10.1115/1.2349573.
Повний текст джерелаАнотація:
A common threat to thick-walled vessels and pipes is thermal shock from operational steady state or transient thermoelastic stresses. As such, boundary conditions must be known or determined in order to reveal the underlying thermal state. For direct problems where all boundary conditions (temperature or flux) are known, the procedure is relatively straightforward and mathematically tractable as shown by many studies. Although more practical from a measurement standpoint, the inverse problem where the boundary conditions must be determined from remotely determined temperature and/or flux data is ill-posed and inherently sensitive to errors in the data. As a result, the inverse route is rarely used to determine thermal stresses. Moreover, most analytical solutions to the inverse problem rely on a host of assumptions that usually restrict their utility to time frames before the thermal wave reaches the natural boundaries of the structure. To help offset these limitations and at the same time solve for the useful case of a thick-walled cylinder exposed to thermal loading on the internal surface, the inverse problem was solved using a least-squares determination of polynomial coefficients based on a generalized direct solution to the heat equation. Once the inverse problem was solved in this fashion and the unknown boundary condition on the internal surface determined, the resulting polynomial was used with the generalized direct solution to determine the internal temperature and stress distributions as a function of time and radial position. For a thick-walled cylinder under an internal transient with external convection, excellent agreement was seen with known temperature histories. Given the versatility of the polynomial solutions advocated, the method appears well suited for many thermal scenarios provided the analysis is restricted to the time interval used to determine the polynomial and the thermophysical properties that do not vary with temperature.
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Ravichandran, P., P. Sugumaran, S. Seshadri, and Altaf H. Basta. "Optimizing the route for production of activated carbon from Casuarina equisetifolia fruit waste." Royal Society Open Science 5, no. 7 (July 2018): 171578. http://dx.doi.org/10.1098/rsos.171578.
Повний текст джерелаАнотація:
This work deals with optimizing the conditions of pyrolysis and type of activator to upgrade the use of Casuarina equisetifolia fruit waste (CFW) as available and a potential precursor, in production of activated carbon (AC). In this respect, the route of activation was carried out through one- and two-step pyrolysis processes, using different chemical activating agents, such as H 3 PO 4 , KOH and ZnCl 2 . The performance of the CFW-based ACs is assessed by estimating the physico-chemical characteristics (pH, electrical conductivity, bulk density and hardness), surface morphology and scanning electron microscopy, together with carbon yield, surface area and adsorption performance of pollutants in aqueous medium (methylene blue, iodine and molasses colour removal efficiencies). The results show that the two-step activation process was more effective than one-step activation for providing high adsorption performance CFW-based ACs. The maximum Brunauer–Emmett–Teller surface area 547.89 m 2 g −1 was produced by using H 3 PO 4 activating agents, and applied two-step pyrolysis. According to the American Water Work Association and based on bulk density of the investigated ACs, we recommend that most of produced ACs are suitable for treating waste water.
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Cartigueyen, S., and K. Mahadevan. "Effects of Thermal Conditions on Microstructure and Mechanical Properties of Cu–SiCp Surface Nanocomposites by Friction Stir Processing Route." Transactions of the Indian Institute of Metals 72, no. 2 (December 14, 2018): 289–305. http://dx.doi.org/10.1007/s12666-018-1480-z.
Повний текст джерела
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Khung, Yit Lung, Siti Hawa Ngalim, Andrea Scaccabarozzi, and Dario Narducci. "Formation of stable Si–O–C submonolayers on hydrogen-terminated silicon(111) under low-temperature conditions." Beilstein Journal of Nanotechnology 6 (January 5, 2015): 19–26. http://dx.doi.org/10.3762/bjnano.6.3.
Повний текст джерелаАнотація:
In this letter, we report results of a hydrosilylation carried out on bifunctional molecules by using two different approaches, namely through thermal treatment and photochemical treatment through UV irradiation. Previously, our group also demonstrated that in a mixed alkyne/alcohol solution, surface coupling is biased towards the formation of Si–O–C linkages instead of Si–C linkages, thus indirectly supporting the kinetic model of hydrogen abstraction from the Si–H surface (Khung, Y. L. et al. Chem. – Eur. J. 2014, 20, 15151–15158). To further examine the probability of this kinetic model we compare the results from reactions with bifunctional alkynes carried out under thermal treatment (<130 °C) and under UV irradiation, respectively. X-ray photoelectron spectroscopy and contact angle measurements showed that under thermal conditions, the Si–H surface predominately reacts to form Si–O–C bonds from ethynylbenzyl alcohol solution while the UV photochemical route ensures that the alcohol-based alkyne may also form Si–C bonds, thus producing a monolayer of mixed linkages. The results suggested the importance of surface radicals as well as the type of terminal group as being essential towards directing the nature of surface linkage.
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RIAZ, S., S. SHAMAILA, B. KHAN, and S. NASEEM. "LOWER TEMPERATURE FORMATION OF ALUMINA THIN FILMS THROUGH SOL–GEL ROUTE." Surface Review and Letters 15, no. 05 (October 2008): 681–88. http://dx.doi.org/10.1142/s0218625x08011858.
Повний текст джерелаАнотація:
Bayerite sol is spun onto single crystal Si substrate, after synthesis and optimization, to obtain films of thickness ~ 0.2 μm. The deposited films are room temperature dried and then heated up to a temperature of 350°C in order to obtain Al 2 O 3. Surface and structural changes, during heating, are observed with optical microscopy. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) are used for post-treatment analyses/characterization. The as-deposited and heated samples' surfaces are smooth as seen with optical and scanning electron microscope in case of optimized conditions. XRD patterns show the change from amorphous to crystalline behavior of these films when heated under various conditions. The most stable form of aluminum oxide, i.e. α- Al 2 O 3, is obtained when samples are heated up to a temperature of as low as 350°C. The thin films are also deposited onto sodalime glass substrates in order to confirm Al 2 O 3 formation through band gap probing. Photoconduction is used to find the energy band gap, which comes out to be 4.7 eV; lower value is correlated to the defect induced states in the band gap.
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Ciobanu, Vladimir, Giacomo Ceccone, Irina Jin, Tudor Braniste, Fei Ye, Francesco Fumagalli, Pascal Colpo, Joydeep Dutta, Jan Linnros та Ion Tiginyanu. "Large-Sized Nanocrystalline Ultrathin β-Ga2O3 Membranes Fabricated by Surface Charge Lithography". Nanomaterials 12, № 4 (18 лютого 2022): 689. http://dx.doi.org/10.3390/nano12040689.
Повний текст джерелаАнотація:
Large-sized 2D semiconductor materials have gained significant attention for their fascinating properties in various applications. In this work, we demonstrate the fabrication of nanoperforated ultrathin β-Ga2O3 membranes of a nanoscale thickness. The technological route includes the fabrication of GaN membranes using the Surface Charge Lithography (SCL) approach and subsequent thermal treatment in air at 900 °C in order to obtain β-Ga2O3 membranes. The as-grown GaN membranes were discovered to be completely transformed into β-Ga2O3, with the morphology evolving from a smooth topography to a nanoperforated surface consisting of nanograin structures. The oxidation mechanism of the membrane was investigated under different annealing conditions followed by XPS, AFM, Raman and TEM analyses.
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Mat Radzi, Salina, M. Z. R. Hanif, and K. M. W. Syamsul. "Optimization of Eugenol Ester Using Statistical Approach of Response Surface Methodology." Materials Science Forum 857 (May 2016): 469–74. http://dx.doi.org/10.4028/www.scientific.net/msf.857.469.
Повний текст джерелаАнотація:
In this study, optimization of eugenol caprylate, a type of ester was successfully carried out using statistical approach of Response surface methodology (RSM). The eugenol ester was synthesized via green route of an enzymatic esterification reaction between eugenol and caprylic acid. Four important enzymology parameters were investigated such as reaction time, temperature, molar ratio of substrate and amount of enzyme. High percentage conversion of ester >80 % was achieved at reaction time of 240.40 minute, 25.52 mg of enzyme’s amount, 1.13 molar ratio substrate and temperature of 56.57 °C based on the optimum conditions. The efficiency of a new dual enzymes system consisting of Novozym 435 and Lipozyme TL IM was also evaluated based on the effect of heat and its reusability on the esterification reaction.
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Redding, J. H. "Route selection for natural gas pipelines in Ireland." Geological Society, London, Engineering Geology Special Publications 4, no. 1 (1987): 467–74. http://dx.doi.org/10.1144/gsl.eng.1987.004.01.56.
Повний текст джерелаАнотація:
AbstractBy the end of 1986, over 400 km of high pressure (70 bar) natural gas pipeline will have been constructed in the Irish Republic, much of it laid in sparsely populated rural areas where topography, hydrology, near surface geology and ground conditions can significantly influence construction feasibility and cost. Identifying, quantifying and (where possible) avoiding areas of potential difficulty or hazard are aspects of route selection to which engineering geology can make an important contribution. This contribution is discussed in relation to the Cork-Dublin pipeline completed in 1982, and the Limerick, Waterford and Mallow lines due for completion this year. In particular, the application and merits of stereo aerial photographic interpretation, superficial geological mapping and field study are outlined, together with the use of more traditional methods of site investigation. Attention is focussed on indigenous engineering geological problems associated with shallow rock, limestone karst, peat bog and poorly drained alluvial and morainic soils. Data acquisition and presentation are discussed within the overall context of civil engineering contract preparation and administration. The usefulness of this approach, particularly for predicting and minimising construction costs, forestalling claims and generally facilitating on-site supervision, is emphasised.
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Hu, Wen Xun, and Amer Shalaby. "Use of Automated Vehicle Location Data for Route- and Segment-Level Analyses of Bus Route Reliability and Speed." Transportation Research Record: Journal of the Transportation Research Board 2649, no. 1 (January 2017): 9–19. http://dx.doi.org/10.3141/2649-02.
Повний текст джерелаАнотація:
Reliability and speed are arguably the most important indicators of surface transit performance for both operators and passengers. They can be influenced by a variety of factors, including service characteristics of bus routes, physical infrastructure, signal settings, traffic conditions and ridership patterns. These factors have often been analyzed individually for their impact on transit reliability or speed. Studies considering more than one factor tend to use one or two transit routes to explore their effects. The study that is the subject of this paper proposed an evaluation framework to guide the selection of an appropriate reliability measure. Regression analysis was applied subsequently to determine the factors that exhibit a statistically significant relationship with transit reliability and speed at both the route and segment levels. Automated vehicle location data of a bus route sample that is representative of the entire bus network in the City of Toronto, Ontario, Canada were used. Features significantly associated with reliability and speed were compared. The results showed that lower transit reliability and speed are significantly associated with the increase in service distance, signalized intersection density, stop density, volume of boarding and alighting passengers, and traffic volume. By segregating bus route segments on the basis of the presence of transit signal priority, the results of the segment-level model demonstrated the beneficial impact of transit signal priority on improving transit reliability.
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Wang, Yanhui, Maroua Bouchneb, Johan Alauzun, and P. Mutin. "Tuning Texture and Morphology of Mesoporous TiO2 by Non-Hydrolytic Sol-Gel Syntheses." Molecules 23, no. 11 (November 17, 2018): 3006. http://dx.doi.org/10.3390/molecules23113006.
Повний текст джерелаАнотація:
The development of powerful synthetic methodologies is paramount in the design of advanced nanostructured materials. Owing to its remarkable properties and low cost, nanostructured TiO2 is widely investigated for applications such as photocatalysis, energy conversion or energy storage. In this article we report the synthesis of mesoporous TiO2 by three different non-hydrolytic sol-gel routes, and we investigate the influence of the synthetic route and of the presence and nature of the solvent on the structure, texture and morphology of the materials. The first route is the well-known ether route, based on the reaction of TiCl4 with iPr2O. The second and third routes, which have not been previously described for the synthesis of mesoporous TiO2, involve the reaction of Ti(OiPr)4 with stoichiometric amounts of acetophenone and benzoic anhydride, respectively. All materials are characterized by XRD, N2 physisorption and SEM. By playing with the non-hydrolytic route used and the reaction conditions (presence of a solvent, nature of the solvent, calcination), it is possible to tune the morphology and texture of the TiO2. Depending on the reaction conditions, a large variety of mesoporous TiO2 nanostructures could be obtained, resulting from the spontaneous aggregation of TiO2 nanoparticles, either rounded nanoparticles, platelets or nanorods. These nanoparticle networks exhibited a specific surface area up to 250 m2 g−1 before calcination, or up to 110 m2 g−1 after calcination.
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Liu, Cai Lin, Yu Rong Zhang, Xian Yan Ren, Hai Jun Yang, and Jun Xiao Yang. "Bislauramide Concrete Foaming Agent: Synthesis and Properties." Key Engineering Materials 477 (April 2011): 205–10. http://dx.doi.org/10.4028/www.scientific.net/kem.477.205.
Повний текст джерелаАнотація:
A bislauramide concrete foaming agent was prepared in good yield by a simple synthetic route using readily available hexamethylenediamine, dodecanoic acid, and chloroacetic acid. The reaction conditions were optimized by changing reaction temperature, reaction time, and/or molar ratios of reactants. Significantly, the concrete foaming agent has very low surface tension and good foaming properties, and shows evident synergistic effects with commercial concrete foaming agents.
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Simons, M. A. J., T. Lamberts, and H. M. Cuppen. "Formation of COMs through CO hydrogenation on interstellar grains." Astronomy & Astrophysics 634 (February 2020): A52. http://dx.doi.org/10.1051/0004-6361/201936522.
Повний текст джерелаАнотація:
Context. Glycoaldehyde, ethylene glycol, and methyl formate are complex organic molecules that have been observed in dark molecular clouds. Because there is no efficient gas-phase route to produce these species, it is expected that a low-temperature surface route existst that does not require energetic processing. CO hydrogenation experiments at low temperatures showed that this is indeed the case. Glyoxal can form through recombination of two HCO radicals and is then further hydrogenated. Aims. Here we aim to constrain the methyl formate, glycolaldehyde, and ethylene glycol formation on the surface of interstellar dust grains through this cold and dark formation route. We also probe the dependence of the grain mantle composition on the initial gas-phase composition and the dust temperature. Methods. A full CO hydrogenation reaction network was built based on quantum chemical calculations for the rate constants and branching ratios. This network was used in combination with a microscopic kinetic Monte Carlo simulation to simulate ice chemistry, taking into account all positional information. After benchmarking the model against CO-hydrogenation experiments, simulations under molecular cloud conditions were performed. Results. Glycoaldehyde, ethylene glycol, and methyl formate are formed in all interstellar conditions we studied, even at temperatures as low as 8 K. This is because the HCO + HCO reaction can occur when HCO radicals are formed close to each other and do not require to diffuse. Relatively low abundances of methyl formate are formed. The final COM abundances depend more on the H-to-CO ratio and less on temperature. Only above 16 K, where CO build-up is less efficient, does temperature start to play a role. Molecular hydrogen is predominantly formed through abstraction reactions on the surface. The most important reaction leading to methanol is H2CO + CH3O → HCO + CH3OH. Our simulations are in agreement with observed COM ratios for mantles that have been formed at low temperatures.
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LUAN, YONG, PINGFENG FU, and XUEGANG DAI. "IMPROVEMENT OF PHOTOCATALYTIC ACTIVITY OF TiO2 VIA COMBINED ROUTE OF METAL DOPING AND SURFACE ACIDIFICATION." Surface Review and Letters 13, no. 04 (August 2006): 429–38. http://dx.doi.org/10.1142/s0218625x06008402.
Повний текст джерелаАнотація:
In the present work, a combined route involving first doping of iron or neodymium ions via sol–gel method followed by acidification of the metal-doped TiO 2 particles for the improvement of the photocatalytic capability of TiO 2 was reported. The obtained metal-doped/acidified TiO 2 photocatalysts were thoroughly characterized by X-ray diffraction, Fourier transform infrared analysis, and photoluminescence emission spectra. At the same time, their photocatalytic activities were evaluated in simulant photodegradation of methylene blue (MB). The results based on these characterizations showed that not only a rutile layer formed on the surface of original TiO 2 particles after surface cladding, but also the doped Fe or Nd ion had a favorable effect on suppression of the electron–hole recombination in the titania under ultraviolet light irradiation. Furthermore, the photocatalytic activity of the material obtained by Fe doping and acidification was substantially improved in comparison to the untreated TiO 2. However, the sample prepared from Nd -doping and acidification of TiO 2 showed decreased capability relative to the untreated TiO 2 in degradation of MB under similar conditions. Finally, the reason why the photocatalytic activities of the obtained catalysts are sensitive to the metal-doping was discussed in details.
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Cartigueyen, S., and K. Mahadevan. "Effects of Heat Generation on Microstructure and Hardness of Cu/SiCp Surface Composite Processed by Friction Stir Processing." Materials Science Forum 830-831 (September 2015): 472–75. http://dx.doi.org/10.4028/www.scientific.net/msf.830-831.472.
Повний текст джерелаАнотація:
In this investigation, copper (Cu) based surface composites reinforced with silicon carbide (SiC) particles were fabricated using friction stir processing (FSP) route. FSP was carried out considering three-factor three-level Box-Behnken design to study the effects of process parameters on peak temperature and hardness of Cu/SiCp surface composites. Microstructural evaluation using optical microscope (OM) revealed that SiCp were uniformly distributed and well – bonded with copper matrix at an adequate heat input conditions. The microhardness of the surface composites were remarkably enhanced than that of base metal. Regression models have been developed for predicting peak temperature and microhardness of processed surface composites and the same were in good agreement with experimental results.
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Martí, Salvador, Narcís Homs, Evandro Brum Pereira, and Pilar Ramírez de la Piscina. "Catalytic behavior of unsupported Co materials in the reformation of ethanol to hydrogen: An in situ diffuse reflectance infrared Fourier transform (DRIFT)-mass spectrometry study." Pure and Applied Chemistry 80, no. 11 (January 1, 2008): 2397–403. http://dx.doi.org/10.1351/pac200880112397.
Повний текст джерелаАнотація:
New unsupported Co catalysts were studied in the ethanol steam-reforming reaction by in situ diffuse reflectance infrared spectroscopy and on-line mass spectrometry (MS) techniques. The initial ethoxy surface species evolved to surface-acyl species and to acetaldehyde intermediate at temperatures ca. 473 K. The subsequent formation of surface-acetate species occurs at ca. 573 K. Further, the acetate species mainly evolve above 573 K to H2 and CO2 products. The route to ketone formation was inhibited on these materials. The presence of surface-hydroxyl groups, which are probably related to the formation of a CoO phase under the reforming conditions, was determined. Alkaline addition shows a beneficial effect on the ethanol steam-reforming over bulk Co catalysts.
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Das, D. P., Armita Dash, and B. K. Mishra. "Facile Fabrication of Single Crystalline Ceria Nanoparticles for Photo-Responsive Applications." Materials Science Forum 734 (December 2012): 127–37. http://dx.doi.org/10.4028/www.scientific.net/msf.734.127.
Повний текст джерелаАнотація:
The present investigation is about fabrication of single-crystalline ceria (CeO2) nanoparticle by a hydrothermal route. High surface area CeO2 was synthesized with transformation of morphology from nanofibers to nanocubes in response to processing conditions. A steady variation of average nanocrystallite size ca. in the range 3.0-16.9 nm and a range of band gap energy from 2.6 to 2.9 eV were measured. The surface area of the nanoparticles varied in the range 16.0136.1 m2/g and the variation in surface area is attributed to the nature of packing of particles. The ceria nanofibers could generate 870.5 µmol of H2 in 3 h of irradiation.
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Ramalho, M. A. F., Ana Cristina Figueiredo de Melo Costa, Lucianna Gama, Ruth Herta Goldsmith Aliaga Kiminami, E. P. Hernandez, Daniel R. Cornejo, and S. M. Rezende. "Nanosize Nickel Ferrite Particles Synthesized by Combustion Reaction: Evaluation of Two Synthesization Routes." Materials Science Forum 530-531 (November 2006): 637–42. http://dx.doi.org/10.4028/www.scientific.net/msf.530-531.637.
Повний текст джерелаАнотація:
Ultrafine magnetic nickel ferrite particles have a significant potential for use in many applications such as magnetic recording media, ferrofluids, microwaves, catalysis and radar-absorbing coatings [1, 2]. Nickel ferrite powders with a nominal NiFe2O4 composition were synthesized by combustion reaction and an evaluation was made of the effect of two different conditions of synthesis on the nanostructural and magnetic characteristics of the resulting powders. Two synthesization routes were studied. The first, NFB, involved the preparation of the powder using a Pyrex beaker heated directly on a hot plate at 480°C until self-ignition occurred. By the second route, NFC, the powder was obtained under the same synthesization condition as the NFB route, but a vitreous silica basin was used. The resulting powders were characterized by X-ray diffraction (XRD), nitrogen adsorption by BET and scanning electron microscopy (SEM). The first route, NFB, proved more favorable to obtain powders with high surface area and, hence, smaller crystalline sizes (5.70 nm) and a superparamagnetic behavior. The NFC route confirmed the feasibility of obtaining powders with a crystalline size of 18.00 nm and a magnetic behavior. Saturation magnetization was 33.18 emu/g and the coercivity field was 25.63 Oe for powders obtained by the NFC route.
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Fujii, Yoshiyuki, Takashi Yamanouchi, Kazuya Suzuki, and Shinya Tanaka. "Comparison of the Surface Conditions of the Inland Ice Sheet, Dronning Maud Land. Antarctica. Derived from Noaa AVHRR Data with Ground Observation." Annals of Glaciology 9 (1987): 72–75. http://dx.doi.org/10.1017/s0260305500000410.
Повний текст джерелаАнотація:
The surface conditions of the inland ice sheet in east Dronning Maud Land, Antarctica, are derived from the NOAA-7 AVHRR data received at Syowa Station and then compared with the ground observations which were collected in November 1984 along a 243 km long traverse route at altitudes ranging from 2700 to 3400 m a.s.l. The variations in the AVHRR data are well related to the distribution of glazed surfaces. The areas with lower albedo, higher surface temperature, lower ratio of channel 2/channel 1, and lower T4-T5 coincide with the areas where a glazed surface has developed. This result is attributed to the fact that the glazed surface is composed of a multi-layered ice crust and that its radiative and thermal properties are closer to ice than to snow. The present study shows that the NOAA AVHRR data are useful for distinguishing bare ice, glazed surfaces, and snow surfaces of the Antarctic ice sheet.
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Fujii, Yoshiyuki, Takashi Yamanouchi, Kazuya Suzuki, and Shinya Tanaka. "Comparison of the Surface Conditions of the Inland Ice Sheet, Dronning Maud Land. Antarctica. Derived from Noaa AVHRR Data with Ground Observation." Annals of Glaciology 9 (1987): 72–75. http://dx.doi.org/10.3189/s0260305500000410.
Повний текст джерелаАнотація:
The surface conditions of the inland ice sheet in east Dronning Maud Land, Antarctica, are derived from the NOAA-7 AVHRR data received at Syowa Station and then compared with the ground observations which were collected in November 1984 along a 243 km long traverse route at altitudes ranging from 2700 to 3400 m a.s.l. The variations in the AVHRR data are well related to the distribution of glazed surfaces. The areas with lower albedo, higher surface temperature, lower ratio of channel 2/channel 1, and lower T4-T5 coincide with the areas where a glazed surface has developed. This result is attributed to the fact that the glazed surface is composed of a multi-layered ice crust and that its radiative and thermal properties are closer to ice than to snow. The present study shows that the NOAA AVHRR data are useful for distinguishing bare ice, glazed surfaces, and snow surfaces of the Antarctic ice sheet.
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Promnimit, Sujira, S. Baruah, U. Lamdu, and Joydeep Dutta. "Hydrothermal Growth of ZnO Hexagonal Nanocrystals: Effect of Growth Conditions." Journal of Nano Research 21 (December 2012): 57–63. http://dx.doi.org/10.4028/www.scientific.net/jnanor.21.57.
Повний текст джерелаАнотація:
Hexagonal ZnO nanocrystals were synthesized through a hydrothermal route under mild conditions (growth temperature of 90°C at atmospheric pressure). Pre-synthesized ZnO nanoparticles were used to serve as nucleation sites for the growth of the nanocrystals. The growth of ZnO nanorods was found to be surface independent. The dimensions of the hexagonal ZnO nanocrystals were observed to be dependent on the concentration of the reactants used (sources of Zn2+ and OH-ions), pH of the growth bath and also on the duration of crystal growth. The average diameter and height of the ZnO nanocrystals was found to be directly proportional to the concentration of the reactants as well as hydrolysis time. The orientation of the nanocrystals was found to be dependent upon the seeding method employed. Hexagonal single crystals of a wide range of dimensions and aspect ratios could be successfully synthesized through a control of growth parameters.
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Pereira, Lennon Ramos, Elaine Cristina Matos Vicentin, Sara Araujo Pereira, Denicar Lina Nascimento Fabris Maeda, Rúbens Prince dos Santos Alves, Robert Andreata-Santos, Francielle Tramontini Gomes de Sousa, et al. "Intradermal Delivery of Dendritic Cell-Targeting Chimeric mAbs Genetically Fused to Type 2 Dengue Virus Nonstructural Protein 1." Vaccines 8, no. 4 (October 1, 2020): 565. http://dx.doi.org/10.3390/vaccines8040565.
Повний текст джерелаАнотація:
Targeting dendritic cells (DCs) by means of monoclonal antibodies (mAbs) capable of binding their surface receptors (DEC205 and DCIR2) has previously been shown to enhance the immunogenicity of genetically fused antigens. This approach has been repeatedly demonstrated to enhance the induced immune responses to passenger antigens and thus represents a promising therapeutic and/or prophylactic strategy against different infectious diseases. Additionally, under experimental conditions, chimeric αDEC205 or αDCIR2 mAbs are usually administered via an intraperitoneal (i.p.) route, which is not reproducible in clinical settings. In this study, we characterized the delivery of chimeric αDEC205 or αDCIR2 mAbs via an intradermal (i.d.) route, compared the elicited humoral immune responses, and evaluated the safety of this potential immunization strategy under preclinical conditions. As a model antigen, we used type 2 dengue virus (DENV2) nonstructural protein 1 (NS1). The results show that the administration of chimeric DC-targeting mAbs via the i.d. route induced humoral immune responses to the passenger antigen equivalent or superior to those elicited by i.p. immunization with no toxic effects to the animals. Collectively, these results clearly indicate that i.d. administration of DC-targeting chimeric mAbs presents promising approaches for the development of subunit vaccines, particularly against DENV and other flaviviruses.
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Liu, Cai Lin, Yu Rong Zhang, Hai Jun Yang, Xian Yan Ren, and Jun Xiao Yang. "Dodecanamide Concrete Foaming Agent: Preparation and Application." Applied Mechanics and Materials 71-78 (July 2011): 799–802. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.799.
Повний текст джерелаАнотація:
A lauramide concrete foaming agent was prepared by a simple synthetic route using readily available N-(2-hydroxyethyl)ethylenediamine, dodecanoic acid, and chloroacetic acid. The reaction conditions were optimized by changing reaction temperature, reaction time, and/or molar ratios of reactants. Significantly, the concrete foaming agent has very low surface tension and good foaming properties, which could be directly used without purification and has widely applicable potentials in low-density foam concrete.
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Corazzi, Maria Angela, Davide Fedele, Giovanni Poggiali, and John Robert Brucato. "Photoprocessing of formamide ice: route towards prebiotic chemistry in space." Astronomy & Astrophysics 636 (April 2020): A63. http://dx.doi.org/10.1051/0004-6361/202037587.
Повний текст джерелаАнотація:
Aims. Formamide (HCONH2) is the simplest molecule containing the peptide bond first detected in the gas phase in Orion-KL and SgrB2. In recent years, it has been observed in high temperature regions such as hot corinos, where thermal desorption is responsible for the sublimation of frozen mantles into the gas phase. The interpretation of observations can benefit from information gathered in the laboratory, where it is possible to simulate the thermal desorption process and to study formamide under simulated space conditions such as UV irradiation. Methods. Here, two laboratory analyses are reported: we studied formamide photo-stability under UV irradiation when it is adsorbed by space relevant minerals at 63 K and in the vacuum regime. We also investigated temperature programmed desorption of pure formamide ice in the presence of TiO2 dust before and after UV irradiation. Results. Through these analyses, the effects of UV degradation and the interaction between formamide and different minerals are compared. We find that silicates, both hydrates and anhydrates, offer molecules a higher level of protection from UV degradation than mineral oxides. The desorption temperature found for pure formamide is 220 K. The desorption temperature increases to 250 K when the formamide desorbs from the surface of TiO2 grains. Conclusions. Through the experiments outlined here, it is possible to follow the desorption of formamide and its fragments, simulate the desorption process in star forming regions and hot corinos, and constrain parameters such as the thermal desorption temperature of formamide and its fragments and the binding energies involved. Our results offer support to observational data and improve our understanding of the role of the grain surface in enriching the chemistry in space.
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Moffat, D., and J. R. Kusel. "Fluorescent lipid uptake and transport in adult Schistosoma mansoni." Parasitology 105, no. 1 (August 1992): 81–89. http://dx.doi.org/10.1017/s0031182000073716.
Повний текст джерелаАнотація:
Fluorescent lipophilic compounds can be used to label the surface membrane of Schistosoma mansoni by adding the compound in small amounts of organic solvents to aqueous medium in vitro. Under these conditions it is difficult to follow routes of distribution of the label. Here we have absorbed nitrobenzoxadiazolamine methylamino–(NBD)–ceramides to positively charged Dowex beads, and incubated the labelled beads with living parasites. The NBD–ceramide transfers to the surface membrane as a patch 50–100 μm in diameter, after which the label can be seen localized in the gut and in a very concentrated form in organelles within the oesophageal gland cells. Subsequently the labelled compound can be found in organelles within other body cells, including subtegumental cells. We show that the labelled ceramide has been transported from the patch in the surface membrane through internal membrane systems to the destination in the gut and oesophageal gland and not transported through the gut via the external medium. A different pattern was observed when NBD–cholesterol was used. The pharynx was rapidly labelled when NBD–cholesterol was added in medium with or without serum or attached to red blood cells only. Diffuse labelling of the surface membrane and oesophageal gland occurred. We have demonstrated a novel route of lipid transport within the parasite. The route requires the surface membrane to have very specialized regions to facilitate such transport.
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Yin, Zhen, Huilin He, Zhenming Wang, Xiaoguo Fang, Chunxiang Xu, Dan Luo, Shouzhen Jiang, and Yan Jun Liu. "Facile In Situ Photochemical Synthesis of Silver Nanoaggregates for Surface-Enhanced Raman Scattering Applications." Nanomaterials 10, no. 4 (April 5, 2020): 685. http://dx.doi.org/10.3390/nano10040685.
Повний текст джерелаАнотація:
Recently, photochemical synthesis has attracted wide interest on in situ preparing the surface-enhanced Raman scattering (SERS) substrate with excellent performance, especially in a compact space and microfluidic channel. Herein, a facile, green and cost-effective approach to in situ photochemically synthesize silver nanoaggregates is demonstrated for SERS applications. By adjusting the photo-irradiation conditions, the morphologies and sizes of the silver nanoaggregates can be deliberately tailored. The synthesized silver nanoaggregates-based substrates exhibit a highly sensitive and reproducible SERS activity with a low detection limit of 10−8 M for 4-Aminothiophenol detection and relative standard deviation of 12.3%, paving an efficient and promising route for in situ SERS-based rapid detection in the environmental monitoring and food quality control.
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Smirnova, Marina Yu, Aleksei S. Bobin, Svetlana N. Pavlova, Arcady V. Ishchenko, Aleksandra V. Selivanova, Vasilii V. Kaichev, Svetlana V. Cherepanova, et al. "Methane dry reforming over Ni catalysts supported on Ce–Zr oxides prepared by a route involving supercritical fluids." Open Chemistry 15, no. 1 (December 29, 2017): 412–25. http://dx.doi.org/10.1515/chem-2017-0046.
Повний текст джерелаАнотація:
AbstractCe0.5Zr0.5O2mixed oxides were prepared in a flow reactor in supercritical isopropanol with acetylacetone as a complexing agent. Variation of the nature of the Zr salt and the temperature of synthesis affected the phase composition, morphology and specific surface area of oxides. X-ray diffraction and Raman spectroscopy studies revealed formation of metastable t” and t’ phases. Oxides are comprised of agglomerates with sizes depending on the synthesis parameters. Loading NiO decreases the specific surface area without affecting X-ray particle sizes of supports. Such sintering was the most pronounced for a support with the highest specific surface area, which resulted in the lowest surface content of Ni as estimated by X-ray photoelectron spectroscopy and in the formation of flattened NiO particles partially embedded into the support. The catalytic activity and stability of these samples in the dry reforming of methane were determined by the surface concentration of Ni and the morphology of its particle controlled by the metal-support interaction, which also depends on the type of catalyst pretreatment. Samples based on ceria-zirconia oxides prepared under these conditions provide a higher specific catalytic activity as compared with the traditional Pechini route, which makes them promising for the practical application.
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Wang, Yuliang, Xuchuan Jiang, and Younan Xia. "A Solution-Phase, Precursor Route to Polycrystalline SnO2Nanowires That Can Be Used for Gas Sensing under Ambient Conditions." Journal of the American Chemical Society 125, no. 52 (December 2003): 16176–77. http://dx.doi.org/10.1021/ja037743f.
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Monteville, Marshall R., and Michael E. Konkel. "Fibronectin-Facilitated Invasion of T84 Eukaryotic Cells by Campylobacter jejuni Occurs Preferentially at the Basolateral Cell Surface." Infection and Immunity 70, no. 12 (December 2002): 6665–71. http://dx.doi.org/10.1128/iai.70.12.6665-6671.2002.
Повний текст джерелаАнотація:
ABSTRACT Previous studies have indicated that the ability to bind to fibronectin is a key feature in successful cell invasion by Campylobacter jejuni. Given the spatial distribution of fibronectin and the architecture of the epithelium, this suggests the possibility that C. jejuni cell invasion might preferentially occur at the basolateral cell surface. To test this hypothesis, we examined the interaction of C. jejuni with T84 human colonic cells. When grown under the appropriate conditions, T84 cells form a polarized cell monolayer. C. jejuni translocation of a T84 cell monolayer appeared to occur via a paracellular (extracellular) route as opposed to a transcellular (intracellular) route based on the finding that a C. jejuni noninvasive mutant translocated as efficiently as its isogenic parent. Additional studies revealed that two distinct C. jejuni wild-type isolates could compete with one another for host cell receptors, whereas a C. jejuni fibronectin-binding-deficient mutant could not compete with a wild-type isolate for host cell receptors. Further, C. jejuni adherence and internalization were significantly inhibited by antifibronectin antibodies but only when cells were first treated with EGTA to expose basolateral cell surfaces. Together, these results support the theory that C. jejuni invasion occurs preferentially at the basolateral surface of eukaryotic cells.