Comparison of properties of electromagnetic clutches with ferromagnetic powder and magnetorheological fluid for low frequency control signals
The article presents the results of laboratory tests for the two electromagnetic clutches of controllable: powder clutch and clutch fluid MR. The research was aimed at comparing the opportunities for coupling the power supply conditions in the low-frequency signals of 1 to 5 Hz. The system uses proprietary software written in Visual Studio C#. The program allows for controlled, laboratory power supply ATTEN PPS3205T-3S.
Study on Performance Analysis of Vehicle Magnetic Powder Clutch with Permanent Magnet
It proposed a new type of magnetic clutch structure--magnetic powder clutch with permanent magnet. The traditional design and calculation method for the magnetic powder clutch is insufficient accuracy, the electromagnetic field finite element method was used to simulate and calculation the magnetic powder clutch with permanent magnet. As a result, magnetic powder clutch with permanent magnet was proved to work well in energy conservation and reduction of energy consumption.
A single amino acid substitution in elongation factor Tu disrupts interaction between the ternary complex and the ribosome
Elongation factor Tu (EF-Tu).GTP has the primary function of promoting the efficient and correct interaction of aminoacyl-tRNA with the ribosome. Very little is known about the elements in EF-Tu involved in this interaction. We describe a mutant form of EF-Tu, isolated in Salmonella typhimurium, that causes a severe defect in the interaction of the ternary complex with the ribosome. The mutation causes the substitution of Val for Gly-280 in domain II of EF-Tu. The in vivo growth and translation phenotypes of strains harboring this mutation are indistinguishable from those of strains in which the same tuf gene is insertionally inactivated. Viable cells are not obtained when the other tuf gene is inactivated, showing that the mutant EF-Tu alone cannot support cell growth. We have confirmed, by partial protein sequencing, that the mutant EF-Tu is present in the cells. In vitro analysis of the natural mixture of wild-type and mutant EF-Tu allows us to identify the major defect of this mutant. Our data shows that the EF-Tu is homogeneous and competent with respect to guanine nucleotide binding and exchange, stimulation of nucleotide exchange by EF-Ts, and ternary complex formation with aminoacyl-tRNA. However various measures of translational efficiency show a significant reduction, which is associated with a defective interaction between the ribosome and the mutant EF-Tu.GTP.aminoacyl-tRNA complex. In addition, the antibiotic kirromycin, which blocks translation by binding EF-Tu on the ribosome, fails to do so with this mutant EF-Tu, although it does form a complex with EF-Tu. Our results suggest that this region of domain II in EF-Tu has an important function and influences the binding of the ternary complex to the codon-programmed ribosome during protein synthesis. Models involving either a direct or an indirect effect of the mutation are discussed.