scholarly journals Improvement of the Barkhausen criterion and the implementation of an intelligent function generator

2017 ◽  
Vol 2017 (4) ◽  
pp. 126-138
Author(s):  
Chia-Wei Lin ◽  
Yen-Ting Chen ◽  
Ying-Chen Chen ◽  
Chung-Cheng Chen
Keyword(s):  
Function Generator ◽  
Barkhausen Criterion

Optimum design method for four-bar function generator using AIS and genetic algorithms

2013 ◽  
Author(s):  
Morteza Saeidi Javash ◽  
Mir Mohammad Ettefagh ◽  
Yousof Ebneddin Hamidi
Keyword(s):  
Genetic Algorithms ◽  
Optimum Design ◽  
Design Method ◽  
Function Generator

An Investigation of the Vibration Testing Method for Small Diameter Endmills

2014 ◽  
Vol 625 ◽  
pp. 134-139
Author(s):  
Takenori Ono
Keyword(s):  
Small Diameter ◽  
Milling Process ◽  
Modal Parameters ◽  
Vibration Testing ◽  
Function Generator ◽  
Testing Method ◽  
Milling Tool ◽  
Compliance Curve ◽  
Vibration Tests ◽  
The Impact

This paper introduced about the in-process vibration testing method for small diameter endmill. By this method, the natural frequency and modal parameters such as mass, damping, and stiffness of the milling tool can be determined in the milling process. An oscillation of the vibrator is controlled by the function generator to apply the impact force at the appropriate cutting period. The measurement setup can determine the compliance curve by the measurement signals of the exiting force and tool deformation. To evaluate the feasibility of the new method, vibration tests were performed on a square endmill which has the diameter of 4 mm in the milling on brass material. Results of vibration tests show that modal parameters of the specific vibration mode can be determined by the new developed method.

scholarly journals DDEL-13. FOCUSED ULTRASOUND MEDIATED BLOOD BRAIN BARRIER DISRUPTION IN A MURINE MODEL OF PONTINE GLIOMA: A SAFETY AND FEASIBILITY STUDY

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii286-iii286
Author(s):  
Zachary Englander ◽  
Hong-Jian Wei ◽  
Antonios Pouliopoulos ◽  
Pavan Upadhyayula ◽  
Chia-Ing Jan ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Focused Ultrasound ◽  
Brain Barrier ◽  
Center Frequency ◽  
Single Element ◽  
Pontine Glioma ◽  
Orthotopic Model ◽  
Function Generator ◽  
Blood Brain ◽  
Glioma Model

Abstract BACKGROUND Drug delivery remains a major obstacle in DIPG, as the blood brain barrier (BBB) limits the penetration of systemic therapies to the brainstem. Focused ultrasound (FUS) is an exciting new technology that, when combined with microbubbles, can open the BBB permitting the entry of drugs across the cerebrovasculature. Given that the utility of FUS in brainstem tumors remains unknown, the purpose of our study was to determine the safety and feasibility of this technique in a murine pontine glioma model. METHODS A syngeneic orthotopic model was established by stereotactic injection of PDGF-B+PTEN-/-p53-/- murine glioma cells (10,000/1ul) into the pons of B6 albino mice. A single-element, spherical-segment FUS transducer (center frequency=1.5MHz) driven by a function generator through a power amplifier (acoustic pressure=0.7MPa) was used with concurrent intravenous microbubble injection (FUS+MB) to sonicate the tumor on post-injection day 14. BBB opening was confirmed with gadolinium-enhanced MRI and Evans blue. Kondziela inverted screen (KIS) testing was completed to measure motor function. Mice were either immediately sacrificed for histopathological assessment or serially monitored for survival. RESULTS In mice treated with FUS (n=11), there was no measured deficit in KIS testing. Additionally, the degree of intra-tumoral hemorrhage and inflammation on H&E in control (n=5) and treated mice (n=5) was similar. Lastly, there was no difference in survival between the groups (control, n=6, median=26 days; FUS, n=6, median=25 days, p>0.05). CONCLUSION FUS+MB is a safe and feasible technique to open the BBB in a preclinical pontine glioma model.

Sign in / Sign up

Export Citation Format

Share Document