Reduction of spindle vibrations in milling machine by active magnetic bearing

In this study, a three-dimensional dynamic model of a milling machine is proposed. The cutting forces of the face milling process were obtained according to the cutting parameters by means of computer simulations and experiment. The cutting forces excited the dynamic model of the system. Relative displacements of the contact point of the cutting tool and the workpiece were obtained by using forced vibration analysis. These displacements affected machining accuracy of the milling machine. Therefore, radial and axial electromagnetic bearings were designed for the active control of the system and they were adapted on the spindle of the milling machine. Thereby the electromagnetic force produced around the rotating spindle reduced vibration amplitude of the cutting tool. The system was operated with and without active control and both these cases were compared. It was revealed that active control diminished cutting tool vibrations and improved machining performanc

Reduction of spindle vibrations in milling machine by active magnetic bearing

In this study, a three-dimensional dynamic model of a milling machine is proposed. The cutting forces of the face milling process were obtained according to the cutting parameters by means of computer simulations and experiment. The cutting forces excited the dynamic model of the system. Relative displacements of the contact point of the cutting tool and the workpiece were obtained by using forced vibration analysis. These displacements affected machining accuracy of the milling machine. Therefore, radial and axial electromagnetic bearings were designed for the active control of the system and they were adapted on the spindle of the milling machine. Thereby the electromagnetic force produced around the rotating spindle reduced vibration amplitude of the cutting tool. The system was operated with and without active control and both these cases were compared. It was revealed that active control diminished cutting tool vibrations and improved machining performanc

Phosphorylation of serine-893 in CARD11 suppresses the formation and activity of the CARD11-BCL10-MALT1 complex in T and B cells

CARD 11 acts as a gatekeeper for adaptive immune responses after T cell or B cell antigen receptor (TCR/BCR) ligation on lymphocytes. PKC theta/beta-catalyzed phosphorylation of CARD11 promotes the assembly of the CARD11-BCL10-MALT1 (CBM) complex and lymphocyte activation. Here, we demonstrated that PKC theta/beta-dependent CARD11 phosphorylation also suppressed CARD11 functions in T or B cells. Through mass spectrometry-based proteomics analysis, we identified multiple constitutive and inducible CARD11 phosphorylation sites in T cells. We demonstrated that a single TCR- or BCR-inducible phosphorylation on Ser 893 in the carboxyl terminus of CARD1 1 prevented the activation of the transcription factor NF-kappa B, the kinase JNK, and the protease MALT1. Moreover, CARD11 Ser(893) phosphorylation sensitized BCR-addicted lymphoma cells to toxicity induced by Bruton's tyrosine kinase (BTK) inhibitors. Phosphorylation of Ser 893 in CARD11 by PKCO controlled the strength of CARD11 scaffolding by impairing the formation of the CBM complex. Thus, PKCO simultaneously catalyzes both stimulatory and inhibitory CARD11 phosphorylation events, which shape the strength of CARD11 signaling in lymphocytes

MALT1 Phosphorylation Controls Activation of T Lymphocytes and Survival of ABC-DLBCL Tumor Cells

The CARMA1/CARD11-BCL10-MALT1 (CBM) complex bridges T and B cell antigen receptor (TCR/BCR) ligation to MALT1 protease activation and canonical nuclear factor kappa B (NF-kappa B) signaling. Using unbiased mass spectrometry, we discover multiple serine phosphorylation sites in the MALT1 C terminus after T cell activation. Phospho-specific antibodies reveal that CBM-associated MALT1 is transiently hyper-phosphorylated upon TCR/CD28 co-stimulation. We identify a dual role for CK1 alpha as a kinase that is essential for CBM signalosome assembly as well as MALT1 phosphorylation. Although MALT1 phosphorylation is largely dispensable for protease activity, it fosters canonical NF-kappa B signaling in Jurkat and murine CD4 T cells. Moreover, constitutive MALT1 phosphorylation promotes survival of activated B cell-type diffuse large B cell lymphoma (ABC-DLBCL) cells addicted to chronic BCR signaling. Thus, MALT1 phosphorylation triggers optimal NF-kappa B activation in lymphocytes and survival of lymphoma cells

Cassini Radio Science

Cassini radio science investigations will be conducted both during the cruise (gravitational wave and conjunction experiments) and the Saturnian tour of the mission (atmospheric and ionospheric occultations, ring occultations, determinations of masses and gravity fields). New technologies in the construction of the instrument, which consists of a portion on-board the spacecraft and another portion on the ground, including the use of the Ka-band signal in addition to that of the S- and X-bands, open opportunities for important discoveries in each of the above scientific areas, due to increased accuracy, resolution, sensitivity, and dynamic range.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43765/1/11214_2004_Article_1436.pd

Design and prototype manufacturing of a torque measurement system

In the present day, automobile manufacturers demand a certain torque range from hinges provided by supply industry. However, there are no torque measurement system used by the industry to measure this kind of mechanisms and the available systems cannot meet expectations. The purpose of this study is to design a computer-based torque measurement system and to produce its prototype. This system will be used to measure torque range of the vehicle front hood hinges and to control whether torque value is suitable or not. The developed system is an integrated mechatronic system that contains such subsystems as mechanical, electronic and control system. It is expected that the developed torque measurement system will fill an important gap in the relevant industrial sectors and will find widespread application area

Mathematical modelling of vacuum pressure on a precision seeder

The purpose of this research was to determine the optimum vacuum pressure of a precision vacuum seeder and to develop mathematical models by using some physical properties of seeds such as one thousand kernel mass, projected area, sphericity and kernel density. Maize, cotton, soya bean, watermelon, melon, cucumber, sugarbeet and onion seeds were used in laboratory tests. One thousand kernel mass, projected area, sphericity and kernel density of seeds varied from 4.3 to 372.5g, 5-77 mm2, 38.4-85.8% and 440-1310 kg m-3, respectively. The optimum vacuum pressure was determined as 4.0 kPa for maize I and II; 3.0 kPa for cotton, soya bean and watermelon I; 2.5 kPa for watermelon II, melon and cucumber; 2.0 kPa for sugarbeet; and 1.5 kPa for onion seeds. The vacuum pressure was predicted by mathematical models. According to the results, the final model could satisfactorily describe the vacuum pressure of the precision vacuum seeder with a chi-square of 2.51 × 10-3, root mean square error of 2.74 × 10-2 and modelling efficiency of 0.99. © 2004 Silsoe Research Institute. All rights reserved. Published by Elsevier Ltd