Switching Action of a Bistable Fluidic Amplifier for Ultrasonic Testing

Air-coupled ultrasonic testing is widely used in the industry for the non-destructive testing of compound materials. It provides a fast and efficient way to inspect large concrete civil infrastructures for damage that might lead to catastrophic failure. Due to the large penetration depths required for concrete structures, the use of traditional piezoelectric transducer requires high power electric systems. In this study, a novel fluidic transducer based on a bistable fluidic amplifier is investigated. Previous experiments have shown that the switching action of the device produces a high-power broadband ultrasonic signal. This study will provide further insight into the switching behaviour of the fluidic switch. Therefore, parametric CFD simulations based on compressible supersonic RANS simulations were performed, varying the inlet pressure and velocity profiles for the control flow. Switching times are analyzed with different methods, and it was found that these are mostly independent of the slope of the velocity profile at the control port. Furthermore, it was found that an inversely proportional relationship exists between flow velocity in the throat and the switching time. The results agree with the theoretical background established by experimental studies that can be found in the literature.

Robust and Automatic Skyline Detection Algorithm Based on MSSDN

Automatic detection of the skyline plays an important role in several applications, such as visual geo-localization, flight control, port security, and mountain peak recognition. Existing skyline detection methods are mostly used under common weather conditions; however, they do not consider bad weather situations, such as rain, which limits their application in real scenes. In this paper, we propose a multi-stream-stage DenseNet to detect skyline automatically under different weather conditions. This model fully considers the adverse factors influencing the skyline and outputs a probability graph of the skyline. Finally, a dynamic programming algorithm is implemented to detect the skyline in images accurately. A comparison with the existing state-of-the-art methods proves that the proposed model shows a good performance under rainy or common weather conditions and exhibits the best detection precision for the public database.

Experiences when irradiating grafts and flaps for skin cancer

"Resection of skin cancer with graft or flap repair may be referred for local postoperative radiotherapy (PORT) to ensure local control." PORT needs to be delivered in a certain time frame after surgery, but this may impact on graft and flap survival. The purpose of this article is to pass on some experience our multidisciplinary team has acquired in order to assist in the management of these cases. Specifically, pertinent issues in patient assessment (history and examination), indications for PORT, the differences between a graft and a flap, and technical considerations in the prescription of radiotherapy to these are covered, accompanied by illustrative cases with appropriate photographs and diagrams. The principal findings are that a conservative approach may need to be taken to ensure graft and flap survival, with PORT reserved for a role in salvage. Other interesting cases cover the lack of acute radiation side effects in flaps; the tendency of acute radiation skin toxicity to move with gravity, and transplanted skin may have a different radiation sensitivity to that of its new environment. We hope that this article will be of use for the multidisciplinary skin oncology team. Further research is needed to validate and confirm our findings.

All-Optical NOT Gate Based on Nanoring Silver-Air Plasmonic Waveguide

In this work, all-optical plasmonic NOT logic gate was proposed by using metal-insulator-metal (MIM) plasmonic waveguides design. This logic gate is numerically analyzed by COMSOL Multiphysics 5.3a. Recently, plasmonics have attracted more attention due to its huge applications in all optical signal processing. Due to it’s highly localization to metallic surfaces, surface plasmon (SP) may have many applications in sub wavelength to guide the optical signal in waveguides to overcome the diffraction limit which considered a big problem in conventional optics. The proposed design of MIM structure is consist of a dielectric waveguides plus metallic claddings, which guide the incident light strongly in the insulator region. Strong localization and relatively simple fabrication make the MIM waveguides the potential key design of Nano-scale all optical devices. Our design consists of symmetric ring structures with straight waveguides which based on MIM structure. All-optical logic gate (NOT gate) behavior is achieved from utilizing the interface between straight waveguides and ring structure waveguides. By switching the activation of the control port, the propagation of the outgoing field in the output waveguide will be changed. As the simulation results show, the proposed structure could operate as an all-optical NOT logic gate. This gate would be a potential component in many applications of all-optical signals processing.

Prototipe Sistem Elektronis Berbantuan PC untuk Pemantauan Kondisi Pasokan Daya Listrik

The prototype of the electronic system aided personal computer for monitoring the condition of the electric power supply have been done. The principle for fabricating the prototype of the electronic system based on the mechanism of handshaking system between electronic systems and line port for a printer. Program embedded on a personal computer with certain specifications for the operation of the system. The prototype of the electronic system consists of 3 (three) main subsystems, namely the diver circuit, sensor circuit, and the circuit of electrical installations analogy. Measuring against the prototype performance is carried out on the port line for the printer, driver circuit, sensor circuit, and electrical installation analogy circuit. The path performance on the port line for the printer is focused on high or low logic on each port. Data port condition is used to process data transmission, while the status and control port conditions are used to process data reception. The performance of the control circuit is very much determined by inputting data from the user so that it is closely related to the data port. The performance of the sensor circuit is very much determined by the condition of the electrical installation analogy, so it is closely related to the status and control ports. The performance of the circuit of electrical installation analogy is marked by the presence of a voltage value, and if the voltage measured in the electrical installation is 220 volts AC, then it is as an installation marker inactive condition. Overall the system is capable of 8 remote monitoring points so that the condition of the electrical power supply through the electrical panel can be monitored at any time.

Effects of Exhaust Gas Recirculation on Knock Intensity of a Downsized Gasoline Spark Ignition Engine

Exhaust gas recirculation (EGR) has gained prominence as a significant method to control port fuel injection engine knock caused by high compression ratio and high intake pressure (IP). In this paper, the effect of EGR on knock intensity was investigated under various conditions which included different compression ratios (9:1, 10:1, 11:1), IPs (1.0 bar, 1.2 bar, 1.4 bar) and intake temperatures (ITs, 20 °C, 40 °C, 60 °C). The torque output being a crucial variant was also considered. The results showed that EGR effectively reduced the maximum amplitude of pressure oscillations (MAPO) and knock intensity factor (KI20). The effect of EGR on knock resistance was more significant at higher compression ratio, IP, and IT. The output torque of the engine reached a peak value with a suitable EGR ratio which also controlled the intensity of knock under different conditions.

Numerical Investigation of Dynamic Characteristics of a Fluidic Device

Fluidic devices are of interest with turbomachinery internal air systems for modulation of cooling air and other applications. Generally, the flow states within a fluidic device are switched by control flow or flows. For most fluidic devices the switching procedure is almost instantaneous and hence it is difficult to characterize the performance of a device experimentally. The objective of this research is to numerically investigate the dynamic characteristics of a control flow operated fluidic device. In this study the dynamic characteristics of a nozzle during switching is considered. The simulations considered the unsteady interaction of the control flow with the nozzle jet for two different switching scenarios namely, switching of high to low flow state and vice versa. The magnitude of static pressure applied at the control port was identified as a controlling parameter and had to be below a critical value to achieve stable switching. The CFD solutions show that this is related to the flow physics and critical momentum flux ratios for switching are calculated for the present device.

Numerical simulation of observed flow phenomena in the supply and control ports and associated feed channels of a mini-vortex amplifier

The trajectory and reach of jets issuing from tangential control ports at the periphery of a vortex amplifier's swirl chamber depend largely on design geometry, size and pressures applied. Excessive control port pressure causes these jets to extend too far across the face of the radial supply ports, to impact on the opposing supply port wall whereupon, they bifurcate to create back diffusion of control port flow along the supply port channels. Flow through vortex amplifier geometry is simulated using a baseline Reynolds stress turbulence model with Computational Fluid Dynamics (CFX) automatic wall treatment. Anisotropic stress and vortex stretching in the swirl chamber and outlet have not prevented convergence (based on normalised vortex amplifier residuals). Known flow structures are reproduced. This paper is focussed on simulation close to pressures needed for bifurcation. Just before the point on an operating characteristic at which bifurcated tangential flow appears, the recirculation zone crossing most of the radial supply stretches to intermittently cut off the radial flow. The steady state results indicate asymmetry between the four ports, as smoke visualisation tests also imply. The transient results are sufficient to demonstrate time-dependent structures and suggest periodicity of flow structures. The model can be used to inform design and operability studies. Moreover, a curious near-wall structure of spinning flow not previously reported has been predicted close to the axis and hugging the swirl chamber wall opposite the outlet, at radii within the forced part of the Rankine vortex.

Mapping Based Energy Efficient Counter Design on FPGA

— In this work, 8-bit counter power optimized counter is designed with help of energy efficient techniques called mapping and simulation activity file in format of Value Change Dump (VCD) file and setting file (*.xpa) to define toggle rate, activity rate and enable rate for the power consumption estimation in order to get energy efficient design. With mapping, there is 33.33%, 34.61%, 36.5%, 36.49%, 36.86%, 36.9% dynamic power reduction in counter when device is operating on 10MHz, 100MHz, 1GHz, 10GHz, 100GHz and 1 THz frequency. This reduction achieved by mapping control signal to control port in place of mapping control signal to LUT (Look Up Table) input. In Resource utilization, when we are mapping the control signal to control port, there is 70.58% less number of LUT and 39.89% less number of IO usage than mapping the control signal to LUT inputs. Spartan-3 FPGA is taken as target device and Xilinx 14.1 ISE is taken as design, synthesis and implementation tools. Verilog HDL(Hardware Description Language) is used to synthesize the counter on FPGA. The power dissipation of the FPGA based energy efficient design is verified using Xilinx XPower tool.