Photochemical Valence Isomerization to High Energy Products – Bicyclobutanes and Oxabicyclobutanes

Author(s):  
Anita Rágyanszki ◽  
Béla Fiser ◽  
Edward Lee‐Ruff ◽  
Joel F. Liebman
Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1308 ◽  
Author(s):  
Arnab Chakraborty ◽  
Răzvan Hirian ◽  
Gregor Kapun ◽  
Viorel Pop

Nanostructured alloy powders of SmCo5 + 10 wt% Fe obtained using recycled material were studied for the first time. The SmCo5 precursor was obtained from commercial magnets recycled by hydrogen decrepitation. The results were compared with identically processed samples obtained using virgin SmCo5 raw material. The samples were synthesized by dry high-energy ball-milling and subsequent heat treatment. Robust soft/hard exchange coupling was observed—with large coercivity, which is essential for commercial permanent magnets. The obtained energy products for the recycled material fall between 80% and 95% of those obtained when using virgin SmCo5, depending on milling and annealing times. These results further offer viability of recycling and sustainability in production. These powders and processes are therefore candidates for the next generation of specialized and nanostructured exchange-coupled bulk industrial magnets.


2021 ◽  
Author(s):  
M. Jarraya ◽  
M. Wallner ◽  
G. Nyman ◽  
S. Ben Yaghlane ◽  
M. Hochlaf ◽  
...  

Abstract Using multi-electron-ion coincidence measurements combined with high level calculations, we show that double ionization of SO2 at 40.81 eV can be state selective. It leads to high energy products, in good yield, via a newly identified mechanim, which is likely to apply widely to multiple ionization by almost all impact processes.


Author(s):  
Verryon Harahap ◽  
Syahrul Humaidi ◽  
Perdamean Sebayang

The making of composites BaFe12O19/ZnO has been done with Wet Milling method used media toluene. Barium M-Ferrit as a matrix and Zinc Oxide as a filler used as the main raw material for composite manufacturing. The milling process of Barium M-Ferrit was done for 12 hours using the High Energy Milling (HEM). Furthermore, the calcination process used furnace at 900 ° C for 4 hours. While Zinc Oxide is milled for 3 hours and calcined at a temperature of 500 oC for 3 hours. The results of Barium M-Ferrit and zinc Oxide mixed using wet milling touluene media for 15 minutes and dried for 1 hour at 200 oC. X-ray diffraction (XRD) showed that BaFe12O19 as a matrix and ZnO as filler with hexagonal crystal structure was formed and the peak showed a single phase, where each BaFe12O19 lattice parameter a = 5.8930 Å, c = 23.1940 Å and ZnO lattice parameter a = 3.2533 Å, c = 5.2073 Å. Characterization Vibrating Sample Magnetometer (VSM) obtained the value of magnetic properties BaFe12O19 powder (matrix) obtained (Ms) magnetic saturation 54.03 emu/g, (Mr) magnet remanent 33.06 emu/g, (Hcj) coercivity 2943 Oe and (BHmax) product energy 190 kGOe and Zinc Oxide as filler values (Ms) magnet saturation 7.84 emu / g, (Mr) magnet remanent 1.27 emu/g, (Hcj) coercivity 152.4 Oe and (BHmax) energy products 10 kGOe. The results of XRD on 50% mass of composites ZnO additions using match software have two phases, namely the presence of ZnO and BaFe12O19 phases which indicate that heterogeneous structures with hexagonal crystal structures. Composite magnetic properties obtained by adding 50% mass of ZnO were (Mr) magnet 39.40 emu/ g, coercivity 2728 Oe, (BHmax) product energy 110 kGOe and for composites 75% mass addition ZnO remanent 39.36 emu/g with coefficient of 1365 Oe and ( BHmax) product energy was 60 kGOe.


2009 ◽  
Vol 24 (2) ◽  
pp. 499-505 ◽  
Author(s):  
Abdulcadir S. Hussein ◽  
Pandiyan Murugaraj ◽  
Colin J. Rix ◽  
David E. Mainwaring

The use of magnetic elements within microelectronic devices are increasingly required in the fabrication of miniature magnetic structures with high energy densities. A synthesis technique is reported that yields Sb-doped CoPt nanoparticles possessing magnetic coercivities as high as 1671 kA/m and magnetic remanences of 295 kA/m, providing an energy product of 20 kJ/m2. Antimony doping was shown to influence the atomic ordering within the alloy sublattices, which allowed the tetragonalization temperature of the nanoparticle structure to be lowered by 200 °C to 400 °C, thereby reducing crystallite growth and sintering during annealing. The “as-synthesized” particles had average diameters of 4.5 nm, which rose to 25 nm on annealing at 600 °C. Synthesis of the doped CoPt particles with high-energy products together with control of particle size distributions in the range of 25 nm allows fabrication of micromagnetic structures by conventional microfabrication techniques such as spin coating and ink-jet printing.


2014 ◽  
Vol 53 (4II) ◽  
pp. 491-504
Author(s):  
Adnan Haider ◽  
Qazi Masood Ahmed ◽  
Zohaib Jawed

Energy inflation has remained a significant topic in macroeconomic policy for the past few decades. This is due to several reasons pertaining to both demand and supply sides. In addition, the history of energy prices has also been characterised by extreme volatilities, Hamilton (2008). This makes forecasting and modelling of energy prices difficult, nevertheless it is important to model and forecast energy prices in all economies. In this paper we have tried to identify the determinants of energy inflation in Pakistan. Energy products are a critical component in any economy, serving as a core input, particularly in manufacturing industries. Moreover, the demand for energy and fuel comes from households fuelling cars and kitchens for which other alternatives are not easily available. This renders the demand inelastic compared to any other good [Edelstein and Kilian (2009)], making economies vulnerable to supply and price shocks. The energy price inflation therefore through cost push inflation and demand-pull inflation has a major impact on core inflation itself, thereby playing a significant role in macroeconomic health of a country. As predicted by Ben Bernanke for the US in 2006, “in the long run energy prices can reduce the productive capacity of US economy if high energy costs make businesses less willing to invest new capital”. The nature of the energy market itself creates a major gap between the oil consumers and oil producers. Whilst demand is inelastic everywhere, supply is limited and is difficult to increase, and confined to certain regions on Earth. This is true particularly for two of the most common energy types: oil and gasoline. The supply of oil is controlled by a few countries, and supply shocks therefore lead to an immediate surge in prices.


Author(s):  
Y. L. Chen

Melt-spun Fe-Nd-B MAGNEQUENCH® ribbons have been produced by Croat et al. with energy products in excess of 10 MG.Oe using a relatively narrow window of composition and quenching speed. The hard magnetic phase has subsequently been identified as the Nd2Fe14B compound which has a very high anisotropy field. The microstructure of the MAGNEQUENCH® ribbon which has a maximum energy product of 14.1 MG•0e was found to consist of equiaxed Nd2Fe14B grains surrounded by a very thin intergranular film. This paper presents the results of some of our earlv work on the microstructural characterization of high energy product MAGNEQUENCH® ribbons having nominal compositions of Nd13Fe82.6B4.4 and Nd15Fe79.9B5.1. The purpose of this investigation was to characterize the microstructures of various MAGNEQUENCH® ribbons for correlation with their magnetic properties.


2015 ◽  
Vol 183 ◽  
pp. 413-427 ◽  
Author(s):  
Michele Aresta ◽  
Angela Dibenedetto ◽  
Tomasz Baran ◽  
Szymon Wojtyła ◽  
Wojciech Macyk

The conversion of CO2 into high energy products (fuels) and the direct carboxylation of C–H bonds require a high energy input. Energy cannot be derived from fossil carbon, in this case. Solar energy can be used instead, with a low environmental impact and good profit. We have studied the use of white light or solar energy in the photoreduction of CO2 and in photocarboxylation reactions, using different semiconductors modified at their surface. Two examples of reduction of CO2 to methanol and CO will be shortly discussed, and two cases of carboxylation of organic substrates. The case of carboxylation of 2,3-dihydrofuran will be discussed in detail.


2020 ◽  
Vol 3 (10) ◽  
pp. 9842-9851
Author(s):  
J. C. Guzmán-Mínguez ◽  
S. Ruiz-Gómez ◽  
L. M. Vicente-Arche ◽  
C. Granados-Miralles ◽  
C. Fernández-González ◽  
...  

1999 ◽  
Vol 5 (S2) ◽  
pp. 42-43
Author(s):  
V.V. Volkov ◽  
Y. Zhu

The magnetic properties of permanent magnets are sensitive to their microstructure. In particular, for the family of Nd(Pr)-Fe-B magnets a very different coercivity and energy products may be obtained by several processing techniques. It was experimentally found that a small excess of Nd over the exact phase composition of Nd2Fe14B plays an important role in obtaining high-energy products during the die-upset processing of the anisotropic hard magnets. However the specific role of the Nd excess on both magnetic structure and microstructure of these die-upset magnets is unclear and controversial. Answers to these questions may help to correctly address some major issues in materials science, e.g. how microstructure is related to magnetic structure of hard magnets, and how to optimize the performance of hard magnets.In-situ TEM magnetizing experiments combined with Lorentz magnetic microscopy in Fresnel-Foucault modes were used to characterize the magnetic structure of die-upset, high energy-product hard magnets Nd13.75Fe80.25B6 and Pr13.75Fe80.25B6.


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