Evaluasi Penggunaan Beton Precast Di Proyek Konstruksi

Innovative of utilization of precast concrete is growing rapidly lately, one of them is precast plate flyslab. The purpose of this research was to evaluate of utilization of precast concrete compared with conventional concrete in construction projects. Research is aiming to determine the level of use of precast concrete, analyzing the aspect of time, costs, workers, and the environmental impact of the use of precast concrete in building. Implementation method used is the literature study, interviews with the participants construction (contractor, consultant, purveyor and supervisor), and field observations of the four projects building two to three floors, including two residences, one home store and a school building. The results of the comparison between the Flyslab precast plate method with conventional method obtained average reduction as follows : the duration of work between 3,94% - 72,97%, the number of workers between 51,33% - 87,45%, budget-estimate plan between 3,05% - 37,57%, and the reduction use of timber as formwork and scaffolding between 90,11% - 98,81%. Overall utilization of precast Flyslab plate is cheaper, faster, laborers are few, and more friendly to the environment if compared with conventional cast plate in place

Tuning intermolecular interactions in di-octyl substituted polyfluorene via hydrostatic pressure

Polyfluorenes (PFs) represent a unique class of poly para-phenylene based blue-emitting polymers with intriguing structure-property relationships. Slight variations in the choice of functionalizing side chains result in dramatic differences in the inter- and intra-chain structures in PFs. We present photoluminescence (PL) and Raman scattering studies of bulk samples and thin films of dioctyl-substituted PF (PF8) under hydrostatic pressure. The bulk sample was further thermally annealed at 1.9 GPa. The PL vibronics of the as-is sample red-shift at an average rate of 26 meV/GPa. The thermally annealed sample is characterized by at least two phase transitions at 1.1 GPa and 4.2 GPa, each of which has a different pressure coefficient for PL vibronics. The Huang-Rhys factor, a measure of the electron-phonon interaction, is found to increase with increasing pressures signaling a higher geometric relaxation of the electronic states. The Raman peaks harden with increasing pressures; the intra-ring C-C stretch frequency at 1600 cm$^{-1}$ has a pressure coefficient of 7.2 cm$^{-1}$/GPa and exhibits asymmetric line shapes at higher pressures, characteristic of a strong electron-phonon interaction. The optical properties of PF8 under high pressure are further contrasted with those of a branched side chain substituted PF.Comment: 22 pages, 10 figure