Pedagogy around graffiti

In this article graffiti is perceived as the art of living with images operated by young artists. The author draws attention to the fact that this art does not only have a negative perception of character, and thus also a social perception (reception). There is explained what the polarization effect of two neighboring generations of graffiti artists in the social space is - open and hidden, in which a presented group of artists tries to manifest their position and presence. Is it worth talking about graffiti in pedagogy in social sciences? The author analyzes it (graffiti) which may not penetrate the structures of life of the young generation, their school, and out-of-school environments, and what does not become the source of rebellion and also a way for establishing a new type of social and educational relationship.

Numerical investigation and Comparative analysis of tunable graphene-gold metasurface based polarizer structures for infrared frequency

We present the comparative analysis of tunable graphene-based metasurface polarizer structure THz frequency range. This polarizer structures have been numerically investigated over the 10 THz to 25 THz of the frequency range. Reflectance co-efficient, phase variation, and phase difference parameters have been investigated to identify the behavior of polarization effect over the range of 10 THz to 25 THz of the frequency. The proposed polarizer has been also investigated for the different shapes of the top gold resonator structure. The proposed structure is tunable for the range of 0.1 eV to 0.9 eV of the graphene Fermi energy. The proposed structure also works on the wide range of the input incident wave of the X and Y polarization. This structure having small, compact tunable design and it can be used as a basic building block in the large THz circuits and structures.

Cationic yet Stronger Donor: A Surprising Partner Effect and the Partner Strategy in Accelerating a Pincer-Co Catalyzed Nitrile Hydroboration Reaction

A strategy to tune the catalytic behavior of a organometallic catalysts rather than ligand engineering is suggested in this work, by computationally studying the effect of (18-crown-6)K+, W(CO)3 and W(PMe3)3 on the reactivity of a Pincer-Co catalyzed nitrile hydroboration reaction through π-coordination to the ligand aromatic ring. These extra additives, as called by the partners, binds the central phenyl ring of the ligand by either dispersion or chemical bonding. The electron-richness of the cobalt center is tuned by the partner, and follows the order (18-crown-6)K+ > W(PMe3)3 > no partner > W(CO)3. While the influence of covalent W-containing partners parallels the electron-richness of W, the non-covalent partner, (18-crown-6)K+, surprisingly increases the donor ability of the Pincer ligand, through polarization effect. All the elementary steps involved in the nitrile hydroboration reaction are influenced by the partner, and the overall barrier is lowered by a surprisingly large extent of 4.9 kcal/mol in the presence of (18-crown-6)K+, suggesting a charming partner effect to be explored by experimentalists that the reactivity of a catalyst can be consecutively tuned without ligand modification.