Impact of surface modifications on hydrogen uptake by Fe@f-MWCNTs and Cu@f-MWCNTs at non-cryogenic temperatures

2017 ◽  
Vol 42 (2) ◽  
pp. 953-959 ◽  
Author(s):  
Madhavi Konni ◽  
Anima S. Dadhich ◽  
Saratchandra Babu Mukkamala
2021 ◽  
Author(s):  
Madhavi Konni ◽  
Manoj Kumar Karnena

Abstract The current research work reports the methods that have been developed to dope the Lithium nanoparticles to the MIL@53-Al surface frameworks without inducing the structures. The prepared MIL@53-Al MOFs and Li/MIL/53-Al were characterized by XRD, TEM, SEM, BET, and TGA. The developed Lithium doped MIL@53-Al and MIL@53-Al were measured for the hydrogen sorption capacities at 298 and 253 K under a pressure of 75 bar. The study reports revealed that sorption capacities of MIL@53-Al enhanced significantly due to the doping of lithium ions; however, doping of these ions should be controlled for obtaining good uptake capacities as the higher concentrations of lithium might damage the frameworks of the synthesized materials. The lithium doping enhances the hydrogen uptake from 1.37 to 1.75 wt % at 253 K and 75 bar pressure.


2018 ◽  
Vol 2 (2) ◽  
pp. 466-471 ◽  
Author(s):  
Madhavi Konni ◽  
Anima S. Dadhich ◽  
Saratchandra Babu Mukkamala

Surface functionalization via decorating nanometal particles on MWCNTs for hydrogen uptake through a spillover mechanism is the key for hydrogen energy storage for transport sectors.


2021 ◽  
Vol 11 (14) ◽  
pp. 6604
Author(s):  
Mohamed F. Aly Aboud ◽  
Zeid A. ALOthman ◽  
Abdulaziz A. Bagabas

Hydrogen storage may be the bottle neck in hydrogen economy, where hydrogen spillover is in dispute as an effective mechanism. In this context, activated carbon (AC) was doped with nitrogen by using ammonia gas, and was further decorated with platinum, palladium, nickel, rhodium, iridium and ruthenium, via an ultrasound-assisted impregnation method, with average particle sizes of around 74, 60, 78, 61, 67 and 38 nm, respectively. The hydrogen storage was compared, before and after modification at both ambient and cryogenic temperatures, for exploring the spillover effect, induced by the decorating transition metals. Ammonia treatment improved hydrogen storage at both 298 K and 77 K, for the samples, where this enhancement was more remarkable at 298 K. Nevertheless, metal decoration reduced the hydrogen uptake of AC for all of the decorated samples other than palladium at cryogenic temperature, but improved it remarkably, especially for iridium and palladium, at room temperature. This observation suggested that metal decoration’s counter effect overcomes hydrogen spillover at cryogenic temperatures, while the opposite takes place at ambient temperature.


Author(s):  
K. A. Fisher ◽  
M. G. L. Gustafsson ◽  
M. B. Shattuck ◽  
J. Clarke

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).


Author(s):  
George Price ◽  
Lizardo Cerezo

Ultrastructural defects of ciliary structure have been known to cause recurrent sino-respiratory infection concurrent with Kartagener's syndrome. (1,2,3) These defects are also known to cause infertility in both males and females. (4) Overall, the defects are defined as the Immotile, or Dyskinetic Cilia Syndrome (DCS). Several ultrastructural findings have been described, including decreased number of cilia, multidirection orientation, fused and compound cilia, membrane blebs, excess matrix in the axoneme, missing outer tubular doublets, translocated doublets, defective radial spokes and dynein arms. A rare but noteworthy ultrastructural finding in DCS is the predominance of microvilli-like structures on the luminal surface of the respiratory epithelium. (5,6) These permanent surface modifications of the apical respiratory epithelium no longer resemble cilia but reflect the ultrastructure of stereocilia, similar to that found in the epidydimal epithelium. Like microvilli, stereocilia are devoid of microtubular ultrastructure in comparison with true cilia.


1991 ◽  
Vol 223 ◽  
Author(s):  
Neeta Agrawal ◽  
R. D. Tarey ◽  
K. L. Chopra

ABSTRACTArgon plasma exposure has been used to induce surface chemical modification of aluminium thin films, causing a drastic change in etch rate in standard HNO3/CH3COOH/H3PO4 etchant. The inhibition period was found to increase with power and Ar plasma exposure time. Auger electron and x-ray photoelectron spectroscopies have indicated formation of an aluminium fluoride (AlF3) surface layer due to fluorine contamination originating from the residue left in the plasma chamber during CF4 processing. The high etch selectivity between unexposed and argon plasma exposed regions has been exploited as a new technique for resistless patterning of aluminium.


Alloy Digest ◽  
2012 ◽  
Vol 61 (2) ◽  

Abstract SSC Invar 36 was developed for use in applications where dimensional stability is essential. It is a nickel-iron alloy with a very low coefficient of thermal expansion from cryogenic temperatures to 200 deg C (390 deg F). It is utilized in aerospace composite tooling and die applications, as well as laser components, and cryogenic components and piping: liquefied natural gas production, storage, and transportation. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on corrosion resistance as well as forming. Filing Code: Fe-158. Producer or source: Sandmeyer Steel Company. Originally published December 2011, revised February 2012.


Alloy Digest ◽  
1966 ◽  
Vol 15 (7) ◽  

Abstract INCONEL alloy X-750 is an age-hardenable, nickel-chromium alloy used for its corrosion and oxidation resistance and high creep rupture strength at temperature up to 1500 F. It also has excellent properties at cryogenic temperatures. It was originally developed for use in gas turbines, but because of its low cost, high strength and weldability it has become the standards choice for a wide variety of applications. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep and fatigue. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-115. Producer or source: Huntington Alloy Products Division, An INCO Company.


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