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321.
Trip-based material handling systems such as AGV systems or lift trucks are often designed with a given flow matrix (or from-to chart), which typically shows the number of loaded trips that the devices must perform per unit time between the workstations. A from-to chart that would result from the parts flow in a facility actually is dictated by the transfer batch size; that is, the number of parts transferred from one workstation to the next in one trip. In this paper, we present analytical and simulation results aimed at determining optimal or nearoptimal transfer batch sizes in manufacturing systems and develop an analytical relationship between the material handling capacity and the expected work in process (WIP) in a manufacturing system. Although the results apply to any discrete-parts flow, trip-based material handling system, they are particularly relevant for the electronics manufacturing industry, where parts (such as printed circuit boards or substrates for flat panel displays) typically are handled as a group (in specially designed containers such as cassettes) and the costs associated with WIP tend to be large. In such applications, the cassette size is the transfer batch size. 相似文献
322.
Hasan Tanak Ferda Erşahin Yavuz Köysal Erbil Ağar Şamil Işık Metin Yavuz 《Journal of molecular modeling》2009,15(10):1281-1290
The Schiff base compound, N-n-Decyl-2-oxo-5-nitro-1-benzylidene-methylamine, has been -synthesized and characterized by IR,
electronic spectroscopy, and X-ray single-crystal determination. Molecular geometry from X-ray experiment of the title compound
in the ground state have been compared using the Hartree-Fock (HF) and density functional method (B3LYP) with 6-31G(d) basis
set. Calculated results show that density functional theory (DFT) at B3LYP/6-31G(d) level can well reproduce the structure
of the title compound. To investigate the solvent effect for the atomic charge distributions of the title compound, self-consistent
reaction field theory with Onsager reaction field model was used. In addition, DFT calculations of the title compound, molecular
electrostatic potential and thermodynamic properties were performed at B3LYP/6-31G(d) level of theory. 相似文献
323.
AbstractThis study involves the development and implementation of a STEM activity containing 3?D printer technology, which is commonly used in STEM education. Out of school STEM courses were organized with seven middle school students studying in the 7th grade and the activities in the course were carried out with a 3D printer. One of the activities in the course is the Balance model. The study reveals the skills students used in the Balance Model activity, which is a 3D STEM activity. The students’ engineering skills were effective through the STEM activity, and they actively used skills such as planning, designing, explaining the design process, creating a realistic product, and testing and evaluating product performance. In addition, it was concluded that the students use their academic and technical skills effectively. The study presents in detail the preparation and implementation process of this activity, which we think may help educators uncover and improve students’ engineering skills. 相似文献