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Chip Control Analysis in Low-Frequency Vibration-Assisted Drilling of Ti–6Al–4V Titanium Alloys
Haojun Yang,Yan Chen,Jiuhua Xu,Mathieu Ladonne,Julian Lonfier,Wenfeng Ding 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.4
In this study, control research of chip morphology and removal is conducted theoretically and experimentally on the basis ofthe low-frequency vibration-assisted drilling process of titanium alloy. The chip morphology prediction model is establishedon the basis of the modifi ed kinematic model, in which the shear angle variation, critical cutting thickness, and stiff ness ofa vibration generator system are considered. In terms of chip removal monitoring, a new monitoring method based on highspeed camera is proposed in this paper. And the reliability of the new method is verifi ed by comparing the signals obtainedby the power sensor and the force sensor. An empirical prediction model for chip removal is also established on the basis ofthe modifi ed kinematical model, the chip morphology prediction model, and the force balance analysis of fragmental chips. Validation experiments show that the mean error of chip radian, which can refl ect the diff erence between the predicted chipmorphology and the experimental one, is 6%. The mean error of the predicted chip removal index compared with the experimentalone is 10.4%. The results obtained show that chip removal can be controlled eff ectively by low rotation speed, smallchip radian, light chip weight, high minimum quantity lubrication cooling pressure, and high oscillation frequency. On thebasis of the prediction model of chip removal, the eff ects of drilling parameters on chip removal behavior are analyzed, andthe optimal drilling parameter combination with highest processing effi ciency is given.
Mateo, Joaquin,Ganji, Gopinath,Lemech, Charlotte,Burris, Howard A.,Han, Sae-Won,Swales, Karen,Decordova, Shaun,DeYoung, M. Phillip,Smith, Deborah A.,Kalyana-Sundaram, Shanker,Wu, Jiuhua,Motwani, Monic American Association for Cancer Research 2017 Clinical Cancer Research Vol.23 No.19
<P><B>Background:</B> The PI3K/protein kinase B (AKT) pathway is commonly activated in several tumor types. Selective targeting of p110β could result in successful pathway inhibition while avoiding the on- and off-target effects of pan-PI3K inhibitors. GSK2636771 is a potent, orally bioavailable, adenosine triphosphate-competitive, selective inhibitor of PI3Kβ.</P><P><B>Methods:</B> We evaluated the safety, pharmacokinetics, pharmacodynamics and antitumor activity of GSK2636771 to define the recommended phase II dose (RP2D). During the dose-selection and dose-escalation stages (parts 1 and 2), patients with <I>PTEN</I>-deficient advanced solid tumors received escalating doses of GSK2636771 (25–500 mg once daily) using a modified 3+3 design to determine the RP2D; tumor type-specific expansion cohorts (part 3) were implemented to further assess tumor responses at the RP2D.</P><P><B>Results:</B> A total of 65 patients were enrolled; dose-limiting toxicities were hypophosphatemia and hypocalcemia. Adverse events included diarrhea (48%), nausea (40%), and vomiting (31%). Single- and repeat-dose exposure increased generally dose proportionally. GSK2636771 400 mg once daily was the RP2D. Phospho/total AKT ratio decreased with GSK2636771 in tumor and surrogate tissue. A castrate-resistant prostate cancer (CRPC) patient harboring <I>PIK3CB</I> amplification had a partial response for over a year; an additional 10 patients derived durable (≥24 weeks) clinical benefit, including two other patients with CRPC with <I>PIK3CB</I> alterations (≥34 weeks). GSK2636771 400 mg once daily orally induced sufficient exposure and target inhibition with a manageable safety profile.</P><P><B>Conclusions:</B> Genomic aberrations of <I>PIK3CB</I> may be associated with clinical benefit from GSK2636771. <I>Clin Cancer Res; 23(19); 5981–92. ©2017 AACR</I>.</P>