scholarly journals When Thermodynamic Properties of Adsorbed Films Depend on Size: Fundamental Theory and Case Study

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1691 ◽  
Author(s):  
Bjørn A. Strøm ◽  
Jianying He ◽  
Dick Bedeaux ◽  
Signe Kjelstrup
Keyword(s):  
Substantial Part ◽  
Small Systems ◽  
Small System ◽  
Spreading Pressure ◽  
Enthalpy Of Adsorption ◽  
Size And Shape ◽  
Adsorbed Films ◽  
Geometric Variables ◽  
System Properties ◽  
First Time

Small system properties are known to depend on geometric variables in ways that are insignificant for macroscopic systems. Small system considerations are therefore usually added to the conventional description as needed. This paper presents a thermodynamic analysis of adsorbed films of any size in a systematic and general way within the framework of Hill’s nanothermodynamics. Hill showed how to deal with size and shape as variables in a systematic manner. By doing this, the common thermodynamic equations for adsorption are changed. We derived the governing thermodynamic relations characteristic of adsorption in small systems, and point out the important distinctions between these and the corresponding conventional relations for macroscopic systems. We present operational versions of the relations specialized for adsorption of gas on colloid particles, and we applied them to analyze molecular simulation data. As an illustration of their use, we report results for CO2 adsorbed on graphite spheres. We focus on the spreading pressure, and the entropy and enthalpy of adsorption, and show how the intensive properties are affected by the size of the surface, a feature specific to small systems. The subdivision potential of the film is presented for the first time, as a measure of the film’s smallness. For the system chosen, it contributes with a substantial part to the film enthalpy. This work can be considered an extension and application of the nanothermodynamic theory developed by Hill. It provides a foundation for future thermodynamic analyses of size- and shape-dependent adsorbed film systems, alternative to that presented by Gibbs.

Helichrysum × kani-isikii (Asteraceae), a new nothospecies from Turkey

Phytotaxa ◽  
2021 ◽  
Vol 507 (4) ◽  
Author(s):  
GÜRKAN SEMİZ ◽  
SERDAR GÖKHAN ŞENOL ◽  
BATIKAN GÜNAL ◽  
MEHMET ÇİÇEK ◽  
VOLKAN EROĞLU
Keyword(s):  
Pollen Size ◽  
Natural Hybrid ◽  
Size And Shape ◽  
First Time

In this study, Helichrysum × kani-isikii (Asteraceae), a new natural hybrid of H. compactum and H. unicapitatum from Babadağ (Denizli, Turkey), is described and investigated in detail for the first time. The new nothospecies is similar to H. compactum and H. unicapitatum, but it has some intermediate morphological and palynological properties that position it between the two putative parents. In the diagnosis of the hybrid, pollen size and shape were found as significant characteristics. Taxonomic, morphological, and palynological characteristics of H. × kani-isikii are compared with those of its putative parents, and some other details are presented with notes on the IUCN category and ecology of the nothospecies. In addition, a key to diagnosing the hybrid from its parental taxa is also provided.

Computer Simulation Study of Adsorption, Isosteric Heat and Phase Transitions of Methane on Graphite

1992 ◽  
Vol 290 ◽  
Author(s):  
Shaoyi Jiang ◽  
Keith E. Gubbins
Keyword(s):  
Isosteric Heat ◽  
Graphite Substrate ◽  
Ensemble Monte Carlo ◽  
Adsorbed Films ◽  
Heat Curve ◽  
First Time ◽  
Grand Canonical ◽  
Adsorption Of Methane ◽  
Incommensurate Phases ◽  
Good Agreement

AbstractWe report Canonical (NVTMC), Grand Canonical (GOMC) and Gibbs Ensemble Monte Carlo (GEMC) simulations for adsorption of methane on graphite. Lennard-Jones (LJ) potentials are used for the intermolecular interactions, and both structured and structureless (10–4–3) solid-fluid potentials are considered. Several sets of methane-methane L.I parameters have been used in the literature, and we compare results obtained with these sets throughout our simulations. The adsorption isotherm and isosteric heat curve are obtained at 77.5 K and found in good agreement with experiments. The commensurateincommensurate transition (CIT) of methane on a graphite substrate with periodically varying adsorbate-adsorbent potential at 40.0 K is studied and is in qualitative agreement with experiment. The effect of varying the corrugation of the fluid-wall potential on the commensurate and incommensurate phases is explored. The GEMC simulations have been carried out to study the vapor-liquid equilibrium (VLE) of a two-dimensional (2D) LJ fluid with system sizes up to 3000 particles. The effect of system sizes on the critical behavior is investigated. The GEMC method has also been successfully applied to study the VLE in 2D adsorbed films for the first time.

scholarly journals MORPHOLOGY AND ATP-ASE OF ISOLATED MITOCHONDRIA

1955 ◽  
Vol 1 (2) ◽  
pp. 127-138 ◽  
Author(s):  
Robert F. Witter ◽  
Michael L. Watson ◽  
Mary A. Cottone
Keyword(s):  
Electron Microscope ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Substantial Part ◽  
Mitochondrial Matrix ◽  
Isolated Mitochondria ◽  
The Matrix ◽  
First Time ◽  
Methods Of Isolation

Changes in the morphology of rat liver mitochondria brought about by different methods of isolation and the concomitant changes in ATP-ase activity were studied. The morphology was investigated with the electron microscope. It was found that the ATP-ase activity of the isolated mitochondria cannot be readily correlated with the morphology of the mitochondria. The ATP-ase found in these preparations was latent, resembling the enzyme described in mitochondria prepared in 0.25 M sucrose. In confirmation of earlier results the use of 0.88 M sucrose yielded preparations with a higher initial ATP-ase than did other methods. Preparation in 0.25 M sucrose resulted in round, swollen mitochondria of which 30 to 40 per cent appeared to have lost a substantial part of the mitochondrial matrix. Preparations in 0.44 to 0.88 M sucrose contained mainly rod-shaped mitochondria plus a small amount of another type of swollen mitochondria. The matrix of mitochondria isolated in 0.88 M sucrose was highly condensed. By the use of 0.44 M sucrose adjusted to pH 6.2 with citric acid, it was possible to isolate, for the first time, mitochondria closely resembling those in situ and containing latent ATP-ase.

scholarly journals RESEARCHES OF MICROMORPHOLOGICAL FEATURES OF SEEDS OF TRIFOLIUM L. OF FLORA OF THE SOUTH CAUCASUS (AZERBAIJAN REPUBLIC,TALYSH) ON ELECTRONIC MICROSCOPE (SEM) AND THEIR TAXONOMIC MEANING

2020 ◽  
Vol 6(72) (2) ◽  
pp. 138-148
Author(s):  
K. A. Mammadyarova ◽  
A. M. Asgarov
Keyword(s):  
Electron Microscope ◽  
Surface Structure ◽  
Morphological Features ◽  
South Caucasus ◽  
Size And Shape ◽  
The Status ◽  
First Time ◽  
Seed Characteristics ◽  
Electronic Microscope ◽  
Seeds And Fruits

In monographs on Trifolium L., in «Atlas of seeds and fruits of the Central and East” as well as in articles published in prestigious journals the importance of seed characteristics in the taxonomy of clovers is pointed. Among the signs of seeds, the shape of the surface, the structure, size, and shape of their hilum are recorded. In addition, in many «Flora» and «Determinants» there is no data of the seeds, especially their micromorphological features in the description of the species of clover. Takinginto account the above, we studied the shape and structure of 8 species of clovers under an electron microscope. For the first time, micromorphological features of seeds of 8 species (T. angustifolium, T. pratense, T. lappaceum, T. subterraneum, T. resupinatum, T. tumens, T. campestre) of clovers (Trifolium L.) of the Talysh flora, collected from the Lankaran-Lerik region of the Azerbaijan Republic, belonging to 4 subgroups and 6 sections were studied on an electron microscope (SEM). The shape of the seeds, their size, color, surface structure, the shape of hilum and their sizes are important taxonomic features. The structure of seeds of the studied species refers to 4 types: seeds with granular surfaces; seeds with tuberculate surfaces; seeds, which have a surface with crystal-like ledges. Features of the structure of seeds can be used, when specifying the status of subgenera; and sections, the remaining morphological features — when determining species of the genus of clover.

scholarly journals Moderate evidence for a Lombard effect in a phylogenetically basal primate

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2328 ◽  
Author(s):  
Christian Schopf ◽  
Sabine Schmidt ◽  
Elke Zimmermann
Keyword(s):  
Auditory Feedback ◽  
Background Noise ◽  
Vocal Communication ◽  
Lombard Effect ◽  
Voice Control ◽  
Mouse Lemurs ◽  
System Properties ◽  
First Time ◽  
The Voice ◽  
Grey Mouse Lemur

When exposed to enhanced background noise, humans avoid signal masking by increasing the amplitude of the voice, a phenomenon termed the Lombard effect. This auditory feedback-mediated voice control has also been found in monkeys, bats, cetaceans, fish and some frogs and birds. We studied the Lombard effect for the first time in a phylogenetically basal primate, the grey mouse lemur,Microcebus murinus. When background noise was increased, mouse lemurs were able to raise the amplitude of the voice, comparable to monkeys, but they did not show this effect consistently across context/individuals. The Lombard effect, even if representing a generic vocal communication system property of mammals, may thus be affected by more complex mechanisms. The present findings emphasize an effect of context, and individual, and the need for further standardized approaches to disentangle the multiple system properties of mammalian vocal communication, important for understanding the evolution of the unique human faculty of speech and language.

scholarly journals A new occurrence of Mucor inaequisporus Dade (Mucorales, Mucoromycota) from soil of the Atlantic Forest in the Brazilian Northeast

Check List ◽  
2021 ◽  
Vol 17 (3) ◽  
pp. 753-758
Author(s):  
Leslie W.S. de Freitas ◽  
Catarina L.F. de Lima ◽  
Carlos A.F. de Souza ◽  
Giovanna C.L. da Cunha ◽  
Joana D.A. Leitão ◽  
...  
Keyword(s):  
Atlantic Forest ◽  
The State ◽  
Size And Shape ◽  
Brazilian Northeast ◽  
First Time

Mucor inaequisporus Dade (Mucorales, Mucoromycota) was isolated for the first time from soil in an area of Atlantic Forest in the state of Alagoas, Brazil. It is distinguished from other species by simultaneously producing erect, undulating and curved sporangiophores, as well as mostly pyriform, oblong, conic, ellipsoid, and obovoid columellae. The sporangiospores vary in size and shape, with some irregular in shape. Aspects of the morphology and distribution of this species are commented on.

How Small a System is Too Small for Studying Liquid Behavior?

1992 ◽  
Vol 291 ◽  
Author(s):  
Marcia. H. Grabow
Keyword(s):  
Computer Simulations ◽  
Thermodynamic Limit ◽  
Small Systems ◽  
Small System ◽  
Liquid Behavior

ABSTRACTAlthough it is often convenient to perform computer simulations with small systems, in liquids the structure obtained using a small system may not be the same that would be obtained in the thermodynamic limit. In this paper we address the question specifically for the case of Stillinger-Weber silicon, identifying the region of density and temperature where small systems give different results from larger systems.

Shape-selective synthesis of Sn(MoO4)2 nanomaterials for catalysis and supercapacitor applications

2016 ◽  
Vol 45 (21) ◽  
pp. 8897-8915 ◽  
Author(s):  
K. Sakthikumar ◽  
Sivasankara Rao Ede ◽  
Soumyaranjan Mishra ◽  
Subrata Kundu
Keyword(s):  
Photocatalytic Reduction ◽  
Selective Synthesis ◽  
Electrochemical Supercapacitors ◽  
Hydrothermal Route ◽  
Size And Shape ◽  
Shape Selective ◽  
First Time ◽  
Supercapacitor Applications

Size and shape-selective Sn(MoO4)2 nanomaterials were synthesized for the first time using hydrothermal route. Needle-like and flake-like nanomaterials were used for two applications, the photocatalytic reduction of nitroarenes and in electrochemical supercapacitors.

Results on the survival of cryptobiotic cyanobacteria samples after exposure to Mars-like environmental conditions

2013 ◽  
Vol 13 (1) ◽  
pp. 35-44 ◽  
Author(s):  
J. -P. de Vera ◽  
S. Dulai ◽  
A. Kereszturi ◽  
L. Koncz ◽  
A. Lorek ◽  
...  
Keyword(s):  
United Arab Emirates ◽  
Higher Plants ◽  
Atmospheric Composition ◽  
Future Research ◽  
Substantial Part ◽  
Pressure Variable ◽  
Dry Conditions ◽  
Desert Areas ◽  
Original Habitat ◽  
First Time

AbstractTests on cyanobacteria communities embedded in cryptobiotic crusts collected in hot and cold deserts on Earth were performed under Mars-like conditions. The simulations were realized as a survey, to find the best samples for future research. During the tests organisms have to resist Mars-like conditions such as atmospheric composition, pressure, variable humidity (saturated and dry conditions) and partly strong UV irradiation. Organisms were tested within their original habitat inside the crust. Nearly half of the cryptobiotic samples from various sites showed survival of a substantial part of their coexisting organisms. The survival in general depended more on the nature of the original habitat and type of the sample than on the different conditions they were exposed to. The best survival was observed in samples from United Arab Emirates (Jebel Ali, 25 km SW of Dubai town) and from Western Australia (near the South edge of Lake Barley), by taxa: Tolypothrix byssoidea, Gloeocapsopsis pleurocapsoides, Nostoc microscopicum, Leptolyngbya or Symploca sp. At both places in salty desert areas members of the Chenopodiaceae family dominated among the higher plants and in the cryptobiotic crust cyanobacterial taxa Tolypothrix was dominant. These organisms were all living in salty locations with dry conditions most of the year. Among them Tolypothrix, Gloeocapsopsis and Symploca sp. were tested in Mars simulation chambers for the first time. The results suggest that extremophiles should be tested with taken into account the context of their original microenvironment, and also the importance to analyse communities of microbes beside single organisms.

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