Concentration-distribution architecture based engine stress test system

2006 ◽  
Author(s):  
Jie Xie ◽  
Bo Yang ◽  
Qiang He
Keyword(s):  
Concentration Distribution ◽  
Stress Test ◽  
Test System

"Anaerobic threshold": problems of determination and validation

1983 ◽  
Vol 55 (4) ◽  
pp. 1178-1186 ◽  
Author(s):  
M. P. Yeh ◽  
R. M. Gardner ◽  
T. D. Adams ◽  
F. G. Yanowitz ◽  
R. O. Crapo
Keyword(s):  
Anaerobic Threshold ◽  
Stress Test ◽  
Venous Blood ◽  
Test System ◽  
Exercise Tests ◽  
Arterial Lactate ◽  
Blood Samples ◽  
Response Data ◽  
Threshold Phenomenon ◽  
Gas Response

Despite the popularity of the concept of “anaerobic threshold” (AT), the noninvasive detection criteria remain subjective, and invasive validations of AT have been based on lactate data of arterial, mixed venous, venous, and capillary blood samples without any concern for the possible lactate differences from these sources. Eight normal subjects underwent two exercise tests on a bicycle ergometer. The protocol consisted of 3 min of rest, 3 min of 0 work load, and a 20 W/min ramp (1 W/3 s) until exhaustion. Simultaneous arterial and venous blood samples were drawn during the second test. Noninvasive gas response data were measured using a computerized breath-by-breath stress test system. Threshold phenomenon of the lactate accumulation was not found. The arterial lactate levels increased continuously after the start of the exercise ramp. The rise in venous lactate lagged behind the rise of the arterial lactate by about 1.5 min, and therefore venous lactate was not considered suitable for AT detection. Four independent exercise physiologists determined AT from the gas response data. The reviewer variability (avg range 16%) of AT for a given subject was representative of AT values reported for untrained and trained individuals (40-70% maximum O2 consumption). We concluded that 1) AT is not detectable using invasive methods (arterial and venous lactates); and 2) the noninvasive gas response determination has such a large range of reviewer variability that it is unsuitable for clinical use.

Electromigration in Power Devices

2020 ◽  
Vol 2020 (1) ◽  
pp. 000078-000084
Author(s):  
Hao Zhuang ◽  
Robert Bauer ◽  
Markus Dinkel
Keyword(s):  
Current Density ◽  
Flip Chip ◽  
Semiconductor Industry ◽  
Stress Test ◽  
Test System ◽  
Circuit Board ◽  
Power Device ◽  
Current Direction ◽  
Power Devices ◽  
Maximum Current

Abstract In the power semiconductor industry, there is continuous development towards higher maximum current capability of devices while device dimensions shrink. This leads to an increase in current density which the devices have to handle, and raises the question if electromigration (EM) is a critical issue here. Generally, an EM failure can be described by the Black’s equation with temperature and current density as the main influencing factors. Normally, the current that the power packages need to handle lies in the range of 100 A. However, it should be noted that power devices exhibit asymmetric sizes of drain and source contacts. This may lead to higher current density at the source leads (area ratio drain/source: ~8x for QFN 5×6). Nevertheless, the source lead area is still much larger than that of the flip chip bumps (i.e., 28 times larger compared to a 100 μm micro-bump). This typically enhances the safety of the power device with respect to EM. However, with regard to future development towards higher maximum current capability, we intended to investigate further on the EM of power devices. In the present work, we focused on the PQFN 5×6 package to study the EM behavior of a power device soldered on a Printed Circuit Board (PCB). We employed the highest current (120 A) and temperature (150 °C) that the stress test system could handle to study EM in accelerated mode. First fails occurred after ~1200 h, which was much earlier than expected from previous flip-chip investigations. In addition, we found separation gaps in the solder joint between drain contact and PCB, which experienced the lowest current density in the whole test. Contradictorily, we observed only minor solder degradation at the source interface, regardless of the higher current density there. Nevertheless, the separating metal interfaces still correlated well with the current direction. Thermal simulations revealed that due to the self-heating of the device by the high current applied, both the drain and source leads were exposed to much higher temperatures (Tmax = 168 °C) than the PCB board which was kept under temperature control at 150 °C. This temperature difference resulted in a thermal gradient between the device and PCB which, in turn, triggered thermal migration (TM) in addition to EM. As TM for the drain contact occurred in the same direction as EM, it enhanced the degradation effect and therefore led to a shorter time-to-failure at the drain. In contrast to this, such an enhanced effect did not occur at the source side. As a result, we observed higher solder degradation at the drain side, which we did confirm by switching the current direction in the test. To minimize the TM effect, a special EM test vehicle, which used a Cu plate instead of the MOSFET chip, was designed and fabricated. Thermal simulation verified that the device operated at similar temperatures as the PCB board. Using this setup, it was possible to study EM in an accelerated mode and, thus, investigate the pure EM behavior of the power device.

Research on Signal Transmission Property of Wireless Sensor Networks for Test System

2012 ◽  
Vol 166-169 ◽  
pp. 1091-1096
Author(s):  
Jianpeng Sun ◽  
Chao Fu Zhu ◽  
Jin Long Zhao
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Transmission Rate ◽  
Stress Test ◽  
Signal Transmission ◽  
Test System ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Wireless Node ◽  
Visual Conditions

By using the key technology of wireless sensor networks, a stress test system was designed, which takes the M2110 wireless sensor networks as a platform. Based on the hardware design and software design of TinyOS2.0 sensor nodes and gateway nodes, the signal transmission performance of wireless sensor networks for the stress test system was tested and researched. In the visual conditions, the maximum communication distance of M2110 wireless node is up to 601 meters. In the non-visual conditions, M2110 wireless node also has a certain signal transmission capacity. On the situation of multi-hop nodes network, the success rate of data transfer has relation to the transmission rate of data packet and the number of hops for nodes.

Development of micro-scale tensile stress test system

2016 ◽  
Vol 2016 (0) ◽  
pp. J2210102
Author(s):  
Kohei FUJIMURA ◽  
Naoki HAYAKAWA ◽  
Kensuke TSUCHIYA ◽  
Toshifumi KAKIUCHI ◽  
Yoshihiko UEMATSU
Keyword(s):  
Tensile Stress ◽  
Stress Test ◽  
Test System ◽  
Micro Scale

scholarly journals System Q: Stress test system.

1984 ◽  
Vol 11 (4) ◽  
pp. 347-351
Author(s):  
MASANORI EGUCHI
Keyword(s):  
Stress Test ◽  
Test System

Multi-Channel OLED Stress Test System

2011 ◽  
Vol 26 (4) ◽  
pp. 532-537 ◽  
Author(s):  
余树福 YU Shu-fu ◽  
胡典钢 HU Dian-gang ◽  
王坚 WANG Jian ◽  
彭俊彪 PENG Jun-biao
Keyword(s):  
Stress Test ◽  
Test System

scholarly journals Impact of Weekly Physical Activity on Stress Response: An Experimental Study

2021 ◽  
Vol 11 ◽  
Author(s):  
Ricardo de la Vega ◽  
Ruth Jiménez-Castuera ◽  
Marta Leyton-Román
Keyword(s):  
Physical Activity ◽  
Stress Response ◽  
Behavioral Response ◽  
Perceived Exertion ◽  
Stress Test ◽  
Test System ◽  
Rating Of Perceived Exertion ◽  
Critical Flicker Fusion ◽  
Sports Science ◽  
Flicker Fusion

The aim of this research is focused on analyzing the alteration of the psychophysiological and cognitive response to an objective computerized stress test (Determination Test - DT-, Vienna test System®), when the behavioral response is controlled. The sample used was sports science students (N = 22), with a mean age of 22.82 (Mage = 22.82; SDyears = 3.67; MPhysicalActivity hours/Week = 7.77; SDhours/week = 3.32) A quasi-experimental design was used in which the response of each participant to the DT test was evaluated. The variable “number of hours of physical activity per week” and the variable “level of behavioral response to stress” were controlled. Before and after this test, the following parameters were measured: activation and central fatigue (Critical Flicker Fusion Threshold (CFF Critical flicker fusion ascending and Critical flicker fusion descending; DC potential), and perceived exertion (Central Rating of Perceived Exertion and Peripheral Rating of Perceived Exertion). Significant differences were found in all of the measures indicated. The usefulness of this protocol and the measures used to analyze the stress response capacity of the study subjects are discussed.

Sign in / Sign up

Export Citation Format

Share Document