Study and Design of an Ultrasonic Flow Tomographic Front-End Multi Level Measurement System

2014 ◽  
Vol 69 (8) ◽  
Author(s):  
Goh Chiew Loon ◽  
Ruzairi Abdul Rahim ◽  
Suzanna Ridzuan Aw ◽  
Fazlul Rahman Mohd Yunus ◽  
Nor Muzakkir Nor Ayob ◽  
...  
Keyword(s):  
Ultrasonic Transducer ◽  
Rapid Evolution ◽  
Flow Visualisation ◽  
Ultrasonic Tomography ◽  
Basic Operation ◽  
Measurement Capability ◽  
Front End ◽  
Trade Offs ◽  
Multi Level ◽  
Primary Focus

With the rapid evolution of electro-acoustical technology, ultrasonic tomography has made considerable progress in industry. An ultrasonic tomography system provides non-invasive and non-intrusive flow visualisation that enhances the understanding of fluid flow processes. The function of ultrasonic tomography is to continuously monitor the dynamics of liquid flow without interrupting the flow. The ultrasonic tomography technique is fully supported by a front-end hardware system. The front end is defined as all the hardware circuitries, including the ultrasonic transducer up to the Analogue-to-Digital Convertors (ADCs), even though the primary focus is the analogue signal processing components. We present here the challenges and trade-offs in the implementation of a front-end system by first explaining the basic operation of such a system, and then indicating what particular performance parameters are needed to ensure optimal system operation. Based on the results from our research studies, we propose an improved front-end multi-level solution that is more accurate than previous solutions and provides real-time measurement capability.

scholarly journals Full-Differential Folded-Cascode Front-End Receiver Amplifier Integrated Circuit for Capacitive Micromachined Ultrasonic Transducers

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 88
Author(s):  
Yiheng Du ◽  
Changde He ◽  
Guowei Hao ◽  
Wendong Zhang ◽  
Chenyang Xue
Keyword(s):  
Power Consumption ◽  
Ultrasonic Transducer ◽  
Equivalent Circuit Model ◽  
Center Frequency ◽  
Gain Bandwidth ◽  
Correct Operation ◽  
Op Amp ◽  
Front End ◽  
Trade Offs ◽  
Folded Cascode

This paper describes the design of a front-end receiver amplifier for capacitive micromachined ultrasonic transducer (CMUT). The proposed operational amplifier (op amp) consists of a full differential folded-cascode amplifier stage followed by a class AB output stage. A feedback resistor is applied between the input and the output of the op amp to make a transimpedance amplifier. We analyzed the equivalent circuit model of the CMUT element operating in the receiving mode and obtained the static output impedance and center frequency characteristics of the CMUT. The op amp gain, bandwidth, noise, and power consumption trade-offs are discussed in detail. The amplifier was fabricated using GlobalFoundries 0.18-μm complementary metal-oxide-semiconductor (CMOS) technology. The open loop gain of the amplifier is approximately 65 dB, and its gain bandwidth product is approximately 29.5 MHz. The measured input reference noise current was 56 nA/√Hz@3 MHz. The amplifier chip area is 325 μm × 150 μm and the op amp is powered by 3.3 V, the static power consumption is 11 mW. We verified the correct operation of our amplifier with CMUT and echo-pulse shown that the CMUT center frequency is 3 MHz with 92% fractional bandwidth.

scholarly journals A Collision Dynamics Model of a Multi-Level Train

2006 ◽  
Author(s):  
Michelle Priante ◽  
David Tyrell ◽  
Benjamin Perlman
Keyword(s):  
Three Dimensional ◽  
Design Parameters ◽  
Collision Dynamics ◽  
Dynamics Model ◽  
Single Level ◽  
High Speeds ◽  
Front End ◽  
Multi Level ◽  
Low Speeds ◽  
Vertical Accelerations

In train collisions, multi-level rail passenger vehicles can deform in modes that are different from the behavior of single level cars. The deformation in single level cars usually occurs at the front end during a collision. In one particular incident, a cab car buckled laterally near the back end of the car. The buckling of the car caused both lateral and vertical accelerations, which led to unanticipated injuries to the occupants. A three-dimensional collision dynamics model of a multi-level passenger train has been developed to study the influence of multi-level design parameters and possible train configuration variations on the reactions of a multi-level car in a collision. This model can run multiple scenarios of a train collision. This paper investigates two hypotheses that could account for the unexpected mode of deformation. The first hypothesis emphasizes the non-symmetric resistance of a multi-level car to longitudinal loads. The structure is irregular since the stairwells, supports for tanks, and draglinks vary from side to side and end to end. Since one side is less strong, that side can crush more during a collision. The second hypothesis uses characteristics that are nearly symmetric on each side. Initial imperfections in train geometry induce eccentric loads on the vehicles. For both hypotheses, the deformation modes depend on the closing speed of the collision. When the characteristics are non-symmetric, and the load is applied in-line, two modes of deformation are seen. At low speeds, the couplers crush, and the cars saw-tooth buckle. At high speeds, the front end of the cab car crushes, and the cars remain in-line. If an offset load is applied, the back stairwell of the first coach car crushes unevenly, and the cars saw-tooth buckle. For the second hypothesis, the characteristics are symmetric. At low speeds, the couplers crush, and the cars remain in-line. At higher speeds, the front end crushes, and the cars remain in-line. If an offset load is applied to a car with symmetric characteristics, the cars will saw-tooth buckle.

scholarly journals Grazing resistance in phytoplankton

Hydrobiologia ◽  
2020 ◽  
Vol 848 (1) ◽  
pp. 237-249 ◽  
Author(s):  
Miquel Lürling
Keyword(s):  
Community Dynamics ◽  
Phytoplankton Community ◽  
Rapid Evolution ◽  
Variable Environment ◽  
Trade Off ◽  
Defense Strategies ◽  
Trade Offs ◽  
Grazing Resistance ◽  
Population And Community Dynamics

AbstractPhytoplankton is confronted with a variable assemblage of zooplankton grazers that create a strong selection pressure for traits that reduce mortality. Phytoplankton is, however, also challenged to remain suspended and to acquire sufficient resources for growth. Consequently, phytoplanktic organisms have evolved a variety of strategies to survive in a variable environment. An overview is presented of the various phytoplankton defense strategies, and costs and benefits of phytoplankton defenses with a zooming in on grazer-induced colony formation. The trade-off between phytoplankton competitive abilities and defenses against grazing favor adaptive trait changes—rapid evolution and phenotypic plasticity—that have the potential to influence population and community dynamics, as exemplified by controlled chemostat experiments. An interspecific defense–growth trade-off could explain seasonal shifts in the species composition of an in situ phytoplankton community yielding defense and growth rate as key traits of the phytoplankton. The importance of grazing and protection against grazing in shaping the phytoplankton community structure should not be underestimated. The trade-offs between nutrient acquisition, remaining suspended, and grazing resistance generate the dynamic phytoplankton community composition.

Study on Performance Analysis of CMOS RF front-end circuits for 2.4GHz Wireless Applications

2012 ◽  
pp. 68-73
Author(s):  
M. Sumathi ◽  
S. Malarvizhi
Keyword(s):  
Performance Analysis ◽  
Low Voltage ◽  
Noise Figure ◽  
Supply Voltage ◽  
Low Noise ◽  
Design System ◽  
Wireless Applications ◽  
Front End ◽  
Trade Offs ◽  
Front End Circuits

In this paper, low voltage design concepts and new CMOS front-end circuits for 2.4GHz wireless applications are presented. The performances of these circuits are analysed and compared with other existing structures using TSMC 0.18-μm CMOS technology scale. The design trade-offs between impedance matching, power gain and noise figure of low-noise amplifiers are highlighted. The advantage of the introduced mixer topology is expressed in terms of conversion gain, noise figure and linearity. At a supply voltage of 1.8V, the design and performance analysis have been performed using Agilent’s Advanced Design System (ADS2009) software.

scholarly journals How humans drive speciation as well as extinction

2016 ◽  
Vol 283 (1833) ◽  
pp. 20160600 ◽  
Author(s):  
J. W. Bull ◽  
M. Maron
Keyword(s):  
Species Diversity ◽  
Human Activities ◽  
Rapid Evolution ◽  
Novel Ecosystem ◽  
No Net Loss ◽  
Extinction Rates ◽  
Trade Offs ◽  
Speciation Rates ◽  
Nuanced Understanding ◽  
Comparable Magnitude

A central topic for conservation science is evaluating how human activities influence global species diversity. Humanity exacerbates extinction rates. But by what mechanisms does humanity drive the emergence of new species? We review human-mediated speciation, compare speciation and known extinctions, and discuss the challenges of using net species diversity as a conservation objective. Humans drive rapid evolution through relocation, domestication, hunting and novel ecosystem creation—and emerging technologies could eventually provide additional mechanisms. The number of species relocated, domesticated and hunted during the Holocene is of comparable magnitude to the number of observed extinctions. While instances of human-mediated speciation are known, the overall effect these mechanisms have upon speciation rates has not yet been quantified. We also explore the importance of anthropogenic influence upon divergence in microorganisms. Even if human activities resulted in no net loss of species diversity by balancing speciation and extinction rates, this would probably be deemed unacceptable. We discuss why, based upon ‘no net loss’ conservation literature—considering phylogenetic diversity and other metrics, risk aversion, taboo trade-offs and spatial heterogeneity. We conclude that evaluating speciation alongside extinction could result in more nuanced understanding of biosphere trends, clarifying what it is we actually value about biodiversity.

A Multi-Level Approach to Concept Selection in Sustainable Design

2014 ◽  
Author(s):  
Daniel Stratton ◽  
Sara Behdad ◽  
Kemper Lewis ◽  
Sundar Krishnamurty
Keyword(s):  
Environmental Sustainability ◽  
Utility Score ◽  
Concept Selection ◽  
Trade Offs ◽  
Design Alternatives ◽  
Multi Level ◽  
Early Phases ◽  
Different Levels ◽  
Selection Of ◽  
Lca Results

The motivation behind this work is to integrate economic and environmental sustainability into decision making at the early phases of design through the development of a hierarchical concept selection method. Life Cycle Assessment (LCA) is a frequently implemented technique used to assess the environmental impacts of products, but it does not provide a simple means for including preference at different levels that can be used for comparison across design alternatives. A method is proposed to accommodate this issue expanding the Hypothetical Equivalents and Inequivalents Method (HEIM) to handle multi-level and multi-attribute trade-offs. The selection of a coffee maker design is used as an example to illustrate the implementation of the method with actual LCA results. The example provides valuable insights into how preferences may be elicited at different hierarchical levels and then combined to create a single utility score that represents to what extent each design alternative is preferred by the decision maker.

scholarly journals Power-Performance Trade-Offs in Nanometer-Scale Multi-Level Caches Considering Total Leakage

2005 ◽  
Author(s):  
R. Bai ◽  
Nam-Sung Kim ◽  
Tae Ho Kgil ◽  
D. Sylvester ◽  
T. Mudge
Keyword(s):  
Nanometer Scale ◽  
Power Performance ◽  
Trade Offs ◽  
Total Leakage ◽  
Multi Level

scholarly journals MULTI-LEVEL OPTIMIZATION OF AN AUTOMOTIVE CLOSED-LOOP SUPPLY CHAIN NETWORK WITH INTERACTIVE FUZZY PROGRAMMING APPROACHES

2018 ◽  
Vol 24 (3) ◽  
pp. 1004-1028 ◽  
Author(s):  
Abdullah YILDIZBAŞI ◽  
Ahmet ÇALIK ◽  
Turan PAKSOY ◽  
Reza ZANJİRANİ FARAHANİ ◽  
Gerhard-Wilhelm WEBER
Keyword(s):  
Supply Chain ◽  
Automotive Industry ◽  
Closed Loop ◽  
Fuzzy Programming ◽  
Decision Makers ◽  
Mixed Integer ◽  
Closed Loop Supply Chain ◽  
Trade Offs ◽  
End Products ◽  
Multi Level

Closed-Loop Supply Chain (CLSC) management has attained appreciable attention over the last few years. CLSC management allows companies to manage their recovery and recycling activities of end products. Due to the latest developments in the world, producers are responsible for the collection, refurbishing, repairing and disassembly of end products at the end of their lives. This paper develops a mixed-integer CLSC model that is inspired by the automotive industry. In this model, we consider three Decision Makers (DM): Plant, Dismantler Center and Customer. Each DM has individual objectives and is responsible for only its own objective function under same constraints. In order to tackle the trade-offs among the objectives, we used four different Interac-tive Fuzzy Programming (IFP) approaches. The applications of the model and solution techniques are investigated in conjectural data. The paper ends with a conclusion and a call for future studies.

Optimization of a high-pressure microwave curing process for T800/X850 carbon fiber-reinforced plastic

2019 ◽  
Vol 32 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Chenglong Guan ◽  
Lihua Zhan ◽  
Guiming Liu ◽  
Xiaobo Yang ◽  
Guangming Dai ◽  
...  
Keyword(s):  
High Pressure ◽  
Heating Rate ◽  
Process Parameters ◽  
Holding Time ◽  
Curing Temperature ◽  
Measurement Capability ◽  
Microwave Curing ◽  
Trade Offs ◽  
Input Control ◽  
Interlaminar Shear

Compared with the conventional composite curing processes, high-pressure microwave curing is a promising technology. In this study, a set of devices for high-pressure microwave curing was built and equipped with real-time temperature measurement capability and a microwave input control system. The orthogonal experimental method was applied to optimize three process parameters, including the heating rate, curing temperature, and holding time, for the high-pressure microwave curing of T800/X850 composites. The effects of the three parameters on the curing quality were studied by measuring the interlaminar shear strength (ILSS) and conducting differential scanning calorimeter tests. The fracture surface of the samples was also examined by scanning electron microscopy. The results showed that the heating rate had a significant effect on the ILSS of the laminates, and the degree of cure of all samples was more than 95% in the tests. Furthermore, the optimal process parameters were determined as follows: heat up to 170°C with a heating rate of 6°C min−1 and a holding time of 90 min. The total curing time of the sample was 42.4%, and the ILSS of the sample was slightly enhanced by 0.31% compared with standard thermal curing. These results could serve to make trade-offs between reducing manufacturing time and preserving the mechanical properties of microwave-cured composites.

Sign in / Sign up

Export Citation Format

Share Document