scholarly journals Dibenzyl Disulfide Adsorption on Cationic Exchanged Faujasites: A DFT Study

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 715 ◽  
Author(s):  
Etienne Paul Hessou ◽  
Miguel Ponce-Vargas ◽  
Jean-Baptiste Mensah ◽  
Frederik Tielens ◽  
Juan Carlos Santos ◽  
...  
Keyword(s):  
Copper Sulfide ◽  
Bond Activation ◽  
Mineral Oil ◽  
Transformer Oil ◽  
Dft Study ◽  
Interaction Energies ◽  
Copper Corrosion ◽  
Subsequent Formation ◽  
High Interaction

Although dibenzyl disulfide (DBDS) is used as a mineral oil stabilizer, its presence in electrical transformer oil is associated as one of the major causes of copper corrosion and subsequent formation of copper sulfide. In order to prevent these undesirable processes, MY zeolites (with M = Li, Na, K, Cs, Cu or Ag) are proposed to adsorb molecularly DBDS. In this study, different MY zeolites are investigated at the DFT+D level in order to assess their ability in DBDS adsorption. It was found that CsY, AgY and CuY exhibit the best compromise between high interaction energies and limited S-S bond activation, thus emerging as optimal adsorbents for DBDS.

scholarly journals Mechanistic insights into the C–H activation of methane mediated by the unsupported and silica-supported VO2OH and CrOOH: a DFT study

RSC Advances ◽  
2021 ◽  
Vol 11 (19) ◽  
pp. 11295-11303
Author(s):  
Shidong Zhao ◽  
Lishuang Ma ◽  
Yanyan Xi ◽  
Hongyan Shang ◽  
Xufeng Lin
Keyword(s):  
Bond Activation ◽  
Support Effect ◽  
Dft Study

The support effect of silica was studied with DFT for the C–H bond activation of methane on a V(v) or a Cr(iii) site. Both of the PCET and HAT mechanisms were computationally characterized.

scholarly journals Effects of Plasma Treated Alumina Nanoparticles on Breakdown Strength, Partial Discharge Resistance, and Thermophysical Properties of Mineral Oil-Based Nanofluids

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3610
Author(s):  
Norhafezaidi Mat Saman ◽  
Izzah Hazirah Zakaria ◽  
Mohd Hafizi Ahmad ◽  
Zulkurnain Abdul-Malek
Keyword(s):  
Thermal Conductivity ◽  
Plasma Treatment ◽  
Base Fluid ◽  
Breakdown Strength ◽  
Partial Discharge ◽  
Mineral Oil ◽  
Transformer Oil ◽  
Alumina Nanoparticles ◽  
Discharge Characteristics ◽  
Nano Alumina

Mineral oil has been chosen as an insulating liquid in power transformers due to its superior characteristics, such as being an effective insulation medium and a great cooling agent. Meanwhile, the performance of mineral oil as an insulation liquid can be further enhanced by dispersing nanoparticles into the mineral oil, and this composition is called nanofluids. However, the incorporation of nanoparticles into the mineral oil conventionally causes the nanoparticles to agglomerate and settle as sediment in the base fluid, thereby limiting the improvement of the insulation properties. In addition, limited studies have been reported for the transformer oil as a base fluid using Aluminum Oxide (Al2O3) as nanoparticles. Hence, this paper reported an experimental study to investigate the significant role of cold plasma treatment in modifying and treating the surface of nano-alumina to obtain a better interaction between the nano-alumina and the base fluid, consequently improving the insulation characteristics such as breakdown voltage, partial discharge characteristics, thermal conductivity, and viscosity of the nanofluids. The plasma treatment process was conducted on the surface of nano-alumina under atmospheric pressure plasma by using the dielectric barrier discharge concept. The breakdown strength and partial discharge characteristics of the nanofluids were measured according to IEC 60156 and IEC 60270 standards, respectively. In contrast, the viscosity and thermal conductivity of the nanofluids were determined using Brookfield DV-II + Pro Automated viscometer and Decagon KD2-Pro conductivity meter, respectively. The results indicate that the 0.1 wt% of plasma-treated alumina nanofluids has shown the most comprehensive improvements in electrical properties, dispersion stability, and thermal properties. Therefore, the plasma treatment has improved the nanoparticles dispersion and stability in nanofluids by providing stronger interactions between the mineral oil and the nanoparticles.

C–C versus C–H bond activation of propyne by Y: A DFT study

2009 ◽  
Vol 907 (1-3) ◽  
pp. 119-125 ◽  
Author(s):  
Tao Hong Li ◽  
Chuan Ming Wang ◽  
Shi Wen Yu ◽  
Xiang Yi Liu ◽  
Hui Fu ◽  
...  
Keyword(s):  
Bond Activation ◽  
Dft Study

Novel Intramolecular CAryl–S Bond Activation by an Electron Rich, Ring-Expanded-NHC-Rh centre: A Combined Experimental and DFT Study

2011 ◽  
Vol 64 (8) ◽  
pp. 1141 ◽  
Author(s):  
Abeer Binobaid ◽  
Kingsley J. Cavell ◽  
Mikhail S. Nechaev ◽  
Benson M. Kariuki
Keyword(s):  
Bond Activation ◽  
Reaction Pathway ◽  
Heterocyclic Carbenes ◽  
Dft Study ◽  
Dft Studies ◽  
X Ray ◽  
Carbene Complex ◽  
Donor Capacity ◽  
Insight Into ◽  
Sulfur Bond

The reaction of (o-MeSPh)-N-functionalized tetrahydropyrimidinium salts with KN(SiMe3)2 and [Rh(COD)Cl]2 in THF leads to the formation of a novel dimeric RhIII bis-carbene complex. The reaction involves the unexpected cleavage/oxidative addition of the aryl-sulfur bond to give dimeric metallated RhIII with bridging MeS< moieties. This unusual reaction is probably a consequence of the sterically imposing structure and strong donor capacity of ring-expanded N-heterocyclic carbenes (RE-NHCs). An X-ray structure of the [(Ph,DIPP-NHC)Rh(Cl)(SMe)2] product complex has been obtained, and DFT studies were undertaken to gain an insight into the reaction pathway.

Bouyancy-Induced Convective Heat Transfer in Cylindrical Transformers Filled With Mineral Oil With Nano-Suspensions

2005 ◽  
Author(s):  
D. G. Walker ◽  
J. L. Davidson ◽  
P. G. Taylor ◽  
K. L. Soh ◽  
Bruce Rogers
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Mineral Oil ◽  
Transformer Oil ◽  
Experimental Measurements ◽  
Transfer Performance ◽  
Heat Transfer Characteristics ◽  
Enhanced Heat Transfer ◽  
Convective Flows ◽  
Good Agreement

The heat transfer characteristics of a transformer using both standard mineral oil and nanodiamond oil was investigated numerically and compared to experimental measurements. The results of the model agree well with the standard oil measurements and with theoretical convective flows from the literature. However, the simulations could not predict the magnitude of the temperature variation in the nanodiamond oil, although the appropriate trend was observed. Because properties of the nanodiamond transformer oil are not well known, good agreement is not expected. Nevertheless, nanodiamond in transformer oil shows enhanced heat transfer performance over standard transformer oil.

The Competitive O–H versus C–H Bond Activation of Ethanol and Methanol by VO2+ in Gas Phase: A DFT Study

2013 ◽  
Vol 117 (24) ◽  
pp. 5161-5170 ◽  
Author(s):  
Lianming Zhao ◽  
Min Tan ◽  
Juan Chen ◽  
Qiuyue Ding ◽  
Xiaoqing Lu ◽  
...  
Keyword(s):  
Gas Phase ◽  
Bond Activation ◽  
Dft Study

Regiospecific C(naphthyl)-H Bond Activation by Platinum(II) - Isolation, Characterization, Reactivity and TD-DFT Study of the Cycloplatinate Complexes

2011 ◽  
pp. n/a-n/a
Author(s):  
Achintesh Narayan Biswas ◽  
Purak Das ◽  
Vivek Bagchi ◽  
Amitava Choudhury ◽  
Pinaki Bandyopadhyay
Keyword(s):  
Bond Activation ◽  
Dft Study ◽  
Td Dft

scholarly journals Study of Breakdown Voltage of Vegetables oil with SiO2 Nanoparticle Additive

2018 ◽  
Vol 12 (1) ◽  
pp. 296
Author(s):  
Muhammad Bin Yahya ◽  
Fatin Amirah Binti Amirrazli
Keyword(s):  
Breakdown Voltage ◽  
Palm Oil ◽  
Coconut Oil ◽  
Mineral Oil ◽  
Partial Discharges ◽  
Transformer Oil ◽  
Different Temperatures ◽  
The Mean ◽  
Insulating Liquid ◽  
Positive Results

<p>This paper investigates the suitability of vegetable oils to replace mineral oil based on its AC breakdown voltage, partial discharge and viscosity. The purpose of the study is to analyze the effect of the nanofluids containing SiO<sub>2</sub> nanoparticle in vegetables oils; namely, Coconut oil and Palm oil. A nanofluid is a fluid containing nanoparticles. However, the precise effects on the electrical properties is still uncertain. For decades, transformers use petroleum-based mineral oil because of its good dielectric properties and cooling capability. Coconut oil (CO) and Palm oil (PO) are thought to be   suitable alternatives to replace mineral oil as transformer oil as they are sustainable and available in plenty as natural resources.  It was obtained in this study that the breakdown voltages of these raw oils have fulfilled the standard specifications of good insulating liquid. However, the addition of SiO<sub>2</sub> did not improve the AC breakdown voltage and viscosity of coconut oil and palm oil at different temperatures. However, the addition of SiO<sub>2</sub> gave positive results in the values of partial discharges in which the presence of the nanoparticles has greatly reduced the mean volume of partial discharges for both coconut oil and palm oil.</p>

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