On the limitations of linear beams for the problems of moving mass-beam interaction using a meshfree method

This paper deals with the capabilities of linear and nonlinear beam theories in predicting the dynamic response of an elastically supported thin beam traversed by a moving mass. To this end, the discrete equations of motion are developed based on Lagrange＇s equations via reproducing kernel particle method （RKPM）. For a particular case of a simply supported beam, Galerkin method is also employed to verify the results obtained by RKPM, and a reasonably good agreement is achieved. Variations of the maximum dynamic deflection and bending moment associated with the linear and nonlinear beam theories are investigated in terms of moving mass weight and velocity for various beam boundary conditions. It is demonstrated that for majority of the moving mass velocities, the differences between the results of linear and nonlinear analyses become remarkable as the moving mass weight increases, particularly for high levels of moving mass velocity. Except for the cantilever beam, the nonlinear beam theory predicts higher possibility of moving mass separation from the base beam compared to the linear one. Furthermore, the accuracy levels of the linear beam theory are determined for thin beams under large deflections and small rotations as a function of moving mass weight and velocity in various boundary conditions.

NiPt nanoparticles supported on CeO_2 nanospheres for efficient catalytic hydrogen generation from alkaline solution of hydrazine

Searching for highly efficient catalysts toward dehydrogenation of hydrazine for chemical hydrogen storage is highly desirable for the development of hydrogen economy. Herein, we report a simple in situ co-reduction synthesis of NiPt nanoparticles supported on CeO_2 nanospheres and their superior catalytic performance for hydrogen generation from alkaline solution of hydrazine at room temperature. Thanks to the strong electronic interaction arising from synergistic effect at atomic lever and support-metal interaction between NiPt and CeO_2.The obtained Ni_5Pt_5-CeO_2 catalyst exhibits 100% hydrogen selectivity and superior catalytic performance for hydrogen generation from alkaline solution of hydrazine at room temperature, with a TOF value of 416 h 1.

Role of conspecifics and personal experience on behavioral avoidance of contaminated flowers by bumblebees

Pollinators use multiple cues whilst foraging in eluding direct cues from flowers and in direct cues from other pollinators. The use of indirect social cues is common in social in sects, such as honeybees and bumblebees, where a social environment facilitates the ability to use such cues. Bumblebees use cues to forage on flowers according to previous foraging experiences. Flowers are an essential food source for pollinators but also pose a high risk of parasite infection through the shared use of flowers leading to parasite spillover. Nevertheless, bumblebees have evolved behavioral defense mechanisms to limit parasite infection by avoiding contaminated flowers. Mechanisms underlying the avoidance of contaminated flowers by bumblebees are poorly understood. Bumblebees were recorded having the choice to forage on non-contaminated flowers and flowers contaminated by a trypan osome gut parasite, Crithidia bombi. The use of different treatments with presence or absence of con specifics on both con taminated and non-contami nated flowers allowed to investigate the role of social visual cues on their pathogen avoidance behavior. Bumblebees are expected to use social visual cues to avoid contaminated flowers. Our study reveals that the presence of a con specific on flowers either con taminated or not does not help bumblebee foragers avoiding contaminated flowers. Nevertheless, bumblebees whereas gaining experie nee tend to avoid their con specific when placed on contami nated flower and copy it whe n on the non-contami nated flower. Our experime nt suggests a detrime ntal impact of floral see nt on disease avoidanee behavior.

Enhanced External Counterpulsation Treatment Inhibitting Advanced Atherosclerotic Plaque Progression by Augmenting the Plaque Wall Stress： An in vivo FSI Study Based on Animal Experiment

Enhance extemal counterpulsation （ECP） procedure has exhbited itself to be an effective therapy for the m anagem entof ischem ic card iovascu lar diseases, However, considering that EECP significantly increases the acute diastolic pressure, whether it will intervene in the chronic progression of advanced plaque causing great concern in clilical applkation, but yet rein ains elusive presently. In the current paper, a flu id-structure interface （FSI） num erical model of artery with p iaque corn ponent w as developed based on in vivo hem odynam ic m easurem entperfotm ed h a porcine model, to caku late the m echanical stresses of the plaque before and during EECP, and h lum to assess the potential effects of long-term EECP treatm ent on plaque progression. The resu Its show that E E C P augm ented the wall shear stress （WSS） and plaque w all stress （PWS） over the card lac cycles, aswell as the spacial oscillatory of W SS （WSSG ）. Durhg EECP treatm ent, the PW S level respectively raised 6.82% and 6.07% in two simulation cases. The currentpilot study suggests that E E C P treatm entre ay p lay a positive effect on inh biting the conthued plaque progression by hcreashg the PW S level over the card iac cycles. Meanwhile, the plaque morphology should be taken into consideration while m aking patient- specific plan for Ion g- term E E C P treatment in clinic.