Dynamic evolution of specific catalytic sites on Pt nanoparticles

2016 ◽  
Vol 6 (1) ◽  
pp. 144-151 ◽  
Author(s):  
Hector Barron ◽  
George Opletal ◽  
Richard D. Tilley ◽  
Amanda S. Barnard

Different types of surface defects are needed for specific types of catalytic reactions, and can be promoted or suppressed by varying the temperature and rates during the early stages of growth.

2019 ◽  
Vol 13 ◽  
pp. 04020
Author(s):  
Giovan Battista Mattii ◽  
Eleonora Cataldo ◽  
Linda Salvi ◽  
Sofia Sbraci ◽  
Francesca Paoli ◽  
...  

In the early stages of planting, the shelter can provide for young vines protection against damage of various kinds. Despite their widespread use, few surveys have been devoted to the study of innovative shelter types and the possible influence of these protections on the physiology and development of plants. In the present experiment, which took place in 2017 in a Tuscan winery, the effects of vine protections by the company OSO (Prato) on single leaf gas exchanges and on the shoot growth in the first year of planting were studied. Three types of shelters with a circular section (completely perforated, partially perforated and closed) have been compared with the traditional full-wall shelters with square section. During the growing season, sprout growth measures, leaf area, leaf gas exchanges and water potential were carried out on the young vines. At the end of the season, shoots were sampled to measure the dry matter accumulated during the season. Among the shelters taken into consideration, it emerges that the completely perforated type guarantees the best development, with differences that are almost always significant for most of the measured parameters with traditional shelters. On the contrary, the closed typology has led to a reduction in growth, in gas exchanges and in water potential. In conclusion, the type completely perforated could constitute a valid alternative to the traditional one because, besides being a useful means for the protection of the vine, it could benefit the development of the root system in the early stages of growth.


Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.


2016 ◽  
Vol 21 (3) ◽  
pp. 279-286 ◽  
Author(s):  
Fatemeh Nasibi ◽  
Khosrow Manouchehri Kalantari ◽  
Roya Zanganeh ◽  
Ghasem Mohammadinejad ◽  
Hakimeh Oloumi

2011 ◽  
Vol 31 (8-9) ◽  
Author(s):  
Walter Michaeli ◽  
Christoph Kremer

Abstract This paper describes an opportunity to compute the surface waviness of compression moulded sheet moulding compound (SMC) parts by simulating residual stresses. First, different types of surface defects occurring on SMC parts are discussed. A method for calculating the surface waviness of the compression moulded part is presented, which combines the simulation of the production process and the structural computation. Modelling of the curing reaction and the development of mechanical properties are discussed and implemented. The potential of the computation method is shown for an automotive fender made of SMC. The results state that the curing reaction of SMC can be well described using the approach of Ng and Manas-Zloczower. The position of the measured waviness on the examined fender is in good agreement with the calculated stress distribution.


1997 ◽  
Vol 40 (2) ◽  
pp. 161-167 ◽  
Author(s):  
M. Kojima ◽  
F. Konishi ◽  
T. Tsukamoto ◽  
K. Yamashita ◽  
K. Kanazawa

2002 ◽  
Vol 89 (1-3) ◽  
pp. 157-159 ◽  
Author(s):  
P Raiteri ◽  
M Celino ◽  
F Valentinotti ◽  
L Miglio

1982 ◽  
Vol 20 ◽  
Author(s):  
P.P. Vaishnava ◽  
P.A. Montano

ABSTRACTIn situ 57Fe Mössbauer spectra are reported for the first-, higher-stage ferric chloride, and a mixed ferric chloride-potassium chloride intercalated graphite catalysts under reduction and Fischer-Tropsch reaction conditions. The mass spectroscopic measurements reveal a different catalytic selectivity for the three catalysts. The first two catalysts predominantly possess a higher selectivity for methane, whereas the third catalyst has higher selectivity for the formation of propane. The differences are attributed to geometrical effects in the catalytic sites of the intercalated compounds.


Zootaxa ◽  
2021 ◽  
Vol 4995 (3) ◽  
pp. 594-600
Author(s):  
MARCO VIOLANTE-HUERTA ◽  
LAURA SANVICENTE-AÑORVE ◽  
MARGARITA HERMOSO-SALAZAR ◽  
AURORA MARRÓN-BECERRA

Lack of knowledge of morphological variations during growth of amphipod crustaceans can result in misidentification of species. In this study, we advance the knowledge of morphological variations of juveniles of the monotypic genus Phrosina Risso, 1822 collected in the oceanic province of the southern Gulf of Mexico. The juveniles differed from the adults mainly in the morphology of pereopods 3 & 4 in that the carpal process is parallel to the propodus, also the rami of the pleopoda consist of only four segments, uropoda 3 are more lanceolate, and the uropoda bear a large prominent spine terminally. These morphological variations have not been described for the species previously. Therefore, the current observations enrich the description of P. semilunata in the early stages of growth and support the need for further taxonomical studiest that could help identify species at different stages of development.  


2018 ◽  
Vol 6 (3) ◽  
pp. 1801471 ◽  
Author(s):  
Hongliang Li ◽  
Menglin Wang ◽  
Laihao Luo ◽  
Jie Zeng

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