An accurate finite strip for analysing deep beams and shear walls

Abstract

SUMMARYA new finite strip for the analysis of 2D elastic problems is presented. Displacement in each of the two inplane directions is interpolated by a set of computed shape functions in the longitudinal direction and, as usual, standard ID Lagrangian shape functions in the transverse direction. Unlike all other finite strips, the unknown parameters of the present finite strip are represented by the physical displacement variables at nodal points. Furthermore, C,-continuity is maintained across the boundaries between adjacent strips. Deep beams with geometric discontinuity can be treated in a standard finite element manner. Several numerical examples are given to demonstrate its accuracy in analysing deep beams and shear walls.

Tailoring the composition of ultrathin, ternary alloy PtRuFe nanowires for the methanol oxidation reaction and formic acid oxidation reaction

“…More importantly, we demonstrated a volcano-type trend in activity across our series of samples, further supporting our claim that chemical composition is crucial to electrocatalytic performance. Moreover, the numbers reproducibly obtained with our ternary NWs are higher in magnitude as compared with other prior reports of PtRuFe catalysts, 6,20,27 and even signicantly outperformed conventional commercial standards, such as PtRu NP/C, as can be observed in Fig. S5.…”

“…Thus, the CV results suggest that the Fe-doped PtRu NWs may actually benet from the complementary benecial effects of (i) the bifunctional mechanism, wherein -OH species dissociated from water and adsorbed onto the Ru surface catalyze the removal of CO adsorbed onto Pt active sites at lower potentials, thereby increasing the overall activity of Pt 1Àx Ru x -based alloys, as well as (ii) the favorable electronic effects associated with PtFe alloys, in which the presence of Fe functionally lowers the d-band center of the Pt, thereby resulting in more d-band vacancies and therefore, overall less susceptibility to poisoning of active sites by CO species formed as intermediates in the indirect oxidation of methanol. 3,6,42,43 In order to evaluate the methanol oxidation performance, all seven nanowire catalysts were tested electrochemically by comparison with commercial PtRu/C serving as a standard and the resulting linear sweep voltammograms (LSVs) are shown in Fig. 6.…”

“…The presence of 30% Ru dopant, as in the Pt 7 Ru 3 system, yielded exceptionally high activities. [6][7][8] As such, we used this particular binary alloy composition as our explicit 'starting point' control sample from which to seek out possible permutations of this overall 30% metal dopant for creating ever more electrochemically active catalysts.…”

“…As such, in recent years, efforts have shied beyond the use of bimetallic catalysts to the study of more complex ternary 'platforms', incorporating three different transition metals. Specically, ternary systems including but not limited to PtRuNi, 3,10,15,16 PtRuFe, [17][18][19][20] PtRuSn, 3 PtRuMo, 3 PtRuRh, 21 and PtRuAu 22 have been investigated as potential electrocatalysts for MOR. The addition of this extra metal not only decreases the overall cost of the catalyst by reducing the amount of Pt utilized but also improves catalytic activity through a favorable synergistic electronic interaction between the Pt active sites and the transition metal dopants.…”

“…Experimentally, PtRuNi nanoparticles synthesized by Park et al 3 demonstrated that the incorporation of Ni into a PtRu alloy resulted in an increase in specic activity, which was as much as $2.2-fold higher as compared with that of the PtRu catalyst, an observation attributable to electron transfer from Ni to Pt. Similarly, Yu et al 18 synthesized and compared the activity of multiple ternary nanoparticle electrocatalysts, i.e. PtRuM ('M' ¼ Co, Ni, Fe); in particular, both PtRuCo and PtRuNi electrocatalysts evinced a favorable 50 mV negative shi in the onset potential for MOR.…”