A Parametric Study of Sound Focusing in Shallow Water by Using Acoustic Contrast Control

2014 ◽  
Vol 22 (04) ◽  
pp. 1450012 ◽  
Author(s):  
Yi-Wei Lin ◽  
Gee-Pinn James Too
Keyword(s):  
Shallow Water ◽  
Frequency Control ◽  
Control Process ◽  
Environmental Parameters ◽  
Specific Area ◽  
Underwater Communications ◽  
Control Zone ◽  
Sound Energy ◽  
Shift Keying ◽  
And Control

Acoustic contrast control is a sound focusing technique applied to personal audio system devices to provide the optimal sound contrast for increasing or decreasing the potential sound energy of a specific area. In this study, acoustic contrast control was developed for sound focusing in shallow water. The advantage of this technique is the establishment of two zones: a bright zone around the user and a dark zone for other regions. In the acoustic contrast control process, computational ocean acoustics are used to calculate the Green's function between the source point and the field point. The effects of environmental parameters, which comprised the number of control sources, transmission frequency, control distances between sources and control zone of a geometric location were simulated. The results show that acoustic contrast control is an effective approach for sound focusing in shallow water that can increase the potential sound energy of a specific area. Employing this technique can also enhance underwater communications by using frequency-shift keying modulation for cross-talking applications.

Recirculation versus flow-through rainbow trout laboratory Flavobacterium columnare challenge

2020 ◽  
Vol 139 ◽  
pp. 213-221
Author(s):  
C Birkett ◽  
R Lipscomb ◽  
T Moreland ◽  
T Leeds ◽  
JP Evenhuis
Keyword(s):  
Rainbow Trout ◽  
Environmental Parameters ◽  
Cumulative Effects ◽  
Flavobacterium Columnare ◽  
Replacement Rate ◽  
Bacterial Concentration ◽  
Water Replacement ◽  
Dose Concentration ◽  
Flow Through ◽  
And Control

Flavobacterium columnare immersion challenges are affected by water-related environmental parameters and thus are difficult to reproduce. Whereas these challenges are typically conducted using flow-through systems, use of a recirculating challenge system to control environmental parameters may improve reproducibility. We compared mortality, bacterial concentration, and environmental parameters between flow-through and recirculating immersion challenge systems under laboratory conditions using 20 rainbow trout families. Despite identical dose concentration (1:75 dilution), duration of challenge, lot of fish, and temperature, average mortality in the recirculating system (42%) was lower (p < 0.01) compared to the flow-through system (77%), and there was low correlation (r = 0.24) of family mortality. Mean days to death (3.25 vs. 2.99 d) and aquaria-to-aquaria variation (9.6 vs. 10.4%) in the recirculating and flow-through systems, respectively, did not differ (p ≥ 0.30). Despite 10-fold lower water replacement rate in the recirculating (0.4 exchanges h-1) compared to flow-through system (4 exchanges h-1), differences in bacterial concentration between the 2 systems were modest (≤0.6 orders of magnitude) and inconsistent throughout the 21 d challenge. Compared to the flow-through system, dissolved oxygen during the 1 h exposure and pH were greater (p ≤ 0.02), and calcium and hardness were lower (p ≤ 0.03), in the recirculating system. Although this study was not designed to test effects of specific environmental parameters on mortality, it demonstrates that the cumulative effects of these parameters result in poor reproducibility. A recirculating immersion challenge model may be warranted to empirically identify and control environmental parameters affecting mortality and thus may serve as a more repeatable laboratory challenge model.

scholarly journals A Novel Fast-Locking ADPLL Based on Bisection Method

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1382
Author(s):  
Xiaoying Deng ◽  
Huazhang Li ◽  
Mingcheng Zhu
Keyword(s):  
High Performance ◽  
Tuning Range ◽  
Frequency Control ◽  
Control Word ◽  
Cmos Process ◽  
Bisection Method ◽  
Reference Frequency ◽  
Wide Tuning Range ◽  
Cascade Structure ◽  
And Control

Based on the idea of bisection method, a new structure of All-Digital Phased-Locked Loop (ADPLL) with fast-locking is proposed. The structure and locking method are different from the traditional ADPLLs. The Control Circuit consists of frequency compare module, mode-adjust module and control module, which is responsible for adjusting the frequency control word of digital-controlled-oscillator (DCO) by Bisection method according to the result of the frequency compare between reference clock and restructure clock. With a high frequency cascade structure, the DCO achieves wide tuning range and high resolution. The proposed ADPLL was designed in SMIC 180 nm CMOS process. The measured results show a lock range of 640-to-1920 MHz with a 40 MHz reference frequency. The ADPLL core occupies 0.04 mm2, and the power consumption is 29.48 mW, with a 1.8 V supply. The longest locking time is 23 reference cycles, 575 ns, at 1.92 GHz. When the ADPLL operates at 1.28 GHz–1.6 GHz, the locking time is the shortest, only 9 reference cycles, 225 ns. Compared with the recent high-performance ADPLLs, our design shows advantages of small area, short locking time, and wide tuning range.

Application of PID in Controllable Pitch Propeller of a Multipurpose Ocean Tug

2013 ◽  
Vol 464 ◽  
pp. 253-257
Author(s):  
Hui Fang Chen
Keyword(s):  
Control System ◽  
Automatic Control ◽  
Automatic Control System ◽  
High Reliability ◽  
Control Process ◽  
Good Control ◽  
Control Performance ◽  
Hardware Configuration ◽  
Design Idea ◽  
And Control

This paper takes the automatic control system of controllable pitch propeller in a multipurpose ocean tug as an example to describe the application of the S7-200 series PLC in the control system of 4500 horse power controllable pitch propeller in detail. The principle of control system is addressed, as well as the hardware configuration, the design idea of the main software and control process. The system shows high reliability, accuracy and good control performance in practical in practical running.

A Design of Coal Mine Security Monitoring Substation Based on ZIGBEE and CAN Bus

2014 ◽  
Vol 971-973 ◽  
pp. 1033-1036
Author(s):  
Hui Jun Wang ◽  
Zhi Qun Yong
Keyword(s):  
Coal Mine ◽  
Can Bus ◽  
Measurement Data ◽  
Environmental Parameters ◽  
Monitoring And Control ◽  
Monitoring And Control System ◽  
Security Monitoring ◽  
Mine Development ◽  
Security Monitoring System ◽  
And Control

In view of the shortcoming such as wiring difficulties, poor scalability, and big cable usage in present mine security monitoring system, this paper puts forward a kind of substation monitoring and control system based on ZIGBEE and CAN. With the core of core, The system collects various measurement data of sensors through the ZIGBEE wireless network, realizes the to collect, and then through the CAN bus to realize the transmission of control commands and data of the up and down machine, and monitor the production parameters and environmental parameters in the coal mine. Experiments show that the monitoring substation is of high real-time performance, good stability, strong expansibility, etc., and can meet the requirements of the coal mine development and mining.

Decoupling Control for Unwinding Tension Control Systems

2012 ◽  
Vol 262 ◽  
pp. 367-371
Author(s):  
Min Bian ◽  
Mei Yang
Keyword(s):  
Control Systems ◽  
Strong Coupling ◽  
Control Process ◽  
Tension Control ◽  
Decoupling Control ◽  
Driver Model ◽  
Control Performance ◽  
Printing Quality ◽  
Simulation Results ◽  
And Control

During the printing process, invariable tension is very important to make sure the high printing quality. It’s well known that the relation of tension and tape velocity is strong-coupling based on the model of tension control, the modeling of tension possesses varies a lot in the control process, and various disturbances are inevitable during printing. All of these make the tension control systems unstable and affect the printing quality. This paper purposes a method to decrease the strong-coupling relation between speed and tension and control the speed-tension accurately. Based on the shaft-less printing press, the unwinding tension model and servo driver model are given. Decoupling controller is designed in this paper, and simulation results show that this method can improve the coupling degree and control performance.

The Isolator of Industrial Automatic Control System Selection and Application

2011 ◽  
Vol 301-303 ◽  
pp. 1714-1718
Author(s):  
Ji Meng Zhang ◽  
Hong Shuo Wang ◽  
Ben De Gan
Keyword(s):  
Control System ◽  
Automatic Control ◽  
Automatic Control System ◽  
Signal Transmission ◽  
Control Process ◽  
Monitoring And Control ◽  
Process Monitoring And Control ◽  
Isolation Device ◽  
System Selection ◽  
And Control

In the automatic control system of industrial field, the production process monitoring and control process is dependent on Mutual coordination of various automation instrument, computer and corresponding actuators. The coordination is accurate or not, the key is signal transmission quality among those agencies. The application and selection of isolation device directly affect signal transmission. This paper discusses the application and choose of industrial site isolator from isolation principle, the principle and choose for isolator, commissioning and parameter selection based on practical application.

scholarly journals Automatic Roadway Backfilling of Caving Gangue for Cutting Roofs by Combined Support on Gob-Side Entry Retaining with No-Pillars: A Case Study

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Shengrong Xie ◽  
Xiaoyu Wu ◽  
Dongdong Chen ◽  
Yaohui Sun ◽  
Junchao Zeng ◽  
...  
Keyword(s):  
Longwall Mining ◽  
Control Process ◽  
Coal Pillar ◽  
Main Roof ◽  
Control Effect ◽  
Mining Technology ◽  
Thick Coal Seam ◽  
Immediate Roof ◽  
Seam Mining ◽  
And Control

Automatic roadways on gob-side entry retaining with no-pillars are used for longwall mining technology. The mining technology with no-pillars can recover coal pillar resources and reduce the amount and cost of roadway excavations. Automatic roadway technology for cutting roofs by combined support on gob-side entry retaining with no-pillars is adopted for the condition of thick immediate roof and medium-thick coal seam mining, cutting off the immediate roof and the main roof on the gob by combined support. The fractured roof forms gangue blocks to fill the gob and loads the overlying strata. The gangue control system is placed on the roadside, which controls the caving gangue to form a gangue rib. In this paper, the viewpoints and key technologies (the roof-cutting technology, the reinforcement and support technology, the gangue rib control technology, and the auxiliary support technology) of automatic roadway technology for cutting roofs by combined support on the gob-side entry retaining with no-pillars are introduced. Furthermore, the formation and control process are explained. The numerical simulation is used to simulate and analyze the roof hanging and the roof cutting structures. In addition, a field engineering test is performed. The field test shows that automatic roadway technology for cutting roofs by combined support on gob-side entry retaining with no-pillars is feasible. This process uses construction techniques and technologies to meet on-site production needs. The combined support has high resistance strength and is shrinkable. In engineering applications, the combined support has a low damage rate. The deformation of the automatic roadway with gob-side entry retaining is small, and the control effect is significant.

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