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The thermal performance of a flat-plate closed-loop pulsating heat pipe (PHP) is experimentally obtained. The PHP is manufactured by means of CNC-milling and vacuum brazing of a stainless steel 316L bottom plate and lid. Each channel of the PHP has a 2∗2 mm2 square cross section. In total 12 channels (6 turns) fit in the 50∗200 mm2 effective area of the PHP. During the experimental investigation,...
Robot-assisted systems have been developed for minimally invasive surgical procedures, which bring tremendous benefits for patients, such as less trauma, less bleeding, and shorter recovery time. Among the contemporary surgical robotic manipulators, flexible serpentine manipulator shows great advantages on operating with complicated nonlinear anatomical constraints, and it can reach deep occluded...
New stringent European Union regulations, on both emission and fuel consumption are driving the automobile manufacturers in continuous search of suitable lightweight materials. Carbon Fiber Reinforced Plastic (CFRP) is one of the most prominent lightweight materials in use. In addition to the benefit of reduction in weight, the inherent properties of CFRP materials such as acoustic emission, electrical...
This paper describes the design and fabrication of an extremely thin-diamond window for terahertz traveling wave tubes. To reinforce the mechanical properties of the micro-crystalline diamond (MCD) incorporated with ultra-nano-crystalline diamond (UNCD), a 60 pm thick, seven-layered composite diamond film was fabricated. It was cut into window disks without lapping and polishing, which were then made...
For travelling-wave tube in millimeter and submillimeter wave frequency bands, an H-plane and E-plane loaded rectangular waveguide is demonstrated as slow-wave structure. The H-plane and E-plane loaded slow-wave structure is designed at W-band for fast verification of the design concept. The cold-test parameters are compared with measurement results.
Design of a sub-THz traveling-wave tube multiplier with a sheet electron and half-period staggered beam slow-wave structure (SWS) is presented. The device consists of two SWS sections separated by drift section. The input one operates in W band and serves for modulation of the electron beam. The output one serves for second-harmonic power extraction in G band.
The results of design, simulation, and experimental testing of an electron-optical system with three elliptic electron beams are presented. Total beam current is 93 mA. The beams are focused by a PPM system with 0.55 T magnitude of the magnetic field. Beam transmission in a rectangular tunnel at over 25 mm distance is demonstrated. The developed electron optical system is assumed to be used in sub-THz-band...
For miniaturized vacuum-tube electron devices at millimeter and submillimeter (THz) bands, a possibility of low-voltage operation is of primary importance. Planar slow-wave structures (SWS) on dielectric substrates are favorable for the low-voltage operation. In this paper, we discuss design, fabrication and cold test of millimeter-wave planar SWSs. We consider the meander and interdigital SWSs, which...
For high gas pressure measurements, a quartz Bourdon-type pressure gauge is one of the highest precision pressure gauges. Setting attitude of the pressure gauges differ according to measurement application. In this paper, the effects of the setting attitude on calibrated values were evaluated. The maximum difference of calibration values by the setting attitude was about 10 kPa, relatively 0.01 %...
Flow cytometer plays a key role in cell sorting and analysis. For a higher detection precision, sheath flow is adopted to avoid the turbulent or vortex effect when the cell flowing through a capillary tube during the cell counting in many commercial cytometers. This method works well when the low flow velocity is relatively low. However, in order to have a higher analysis efficiency for clinical laboratories,...
We have previously proposed the use of acoustic microbubble delivery in blood vessels to improve the efficacy of acoustic targeted drug therapy. The technical requirement is the detailed visualization of the blood vessel network for navigation around a target such as a tumor. For this purpose, we have used three-dimensional (3D) Doppler-mode volumes to obtain the blood vessel structure. However, since...
To facilitate the development and application of ultrasound shear wave elastography (SWE) in arteries, it is necessary to understand the nature of shear waves (SWs) propagating in pressurized anisotropic tubes embedded in softer surrounding tissues and blood. Phantom models are widely used to study SWE in tubular settings mimicking arterial geometry without yet considering anisotropy. To investigate...
Pulmonary embolism (PE) is the third-leading cause of death from cardiovascular disease. Currently, PE is treated via catheter-delivered, ultrasound-enhanced thrombolysis using side-fired, low-intensity ultrasound energy (0.5 W/cm2) at ∼2 MHz to reduce the required dose of thrombolytic drugs because of the enhanced drug penetration into the clot. However, several clinical studies have shown that the...
Sub-diffraction imaging, also known as ultrasound localization microscopy, is a novel method that can overcome the fundamental diffraction limit by localizing spatially isolated microbubbles. This method requires the use of a low concentration of microbubbles to ensure that they are spatially isolated. For in vivo microvascular imaging, especially for cancer tissue with high microvascular density,...
Phase-change contrast agents (PCCAs) provide advantages over conventional microbubble contrast agents, including increased circulation time and the ability to extravasate from leaky tumor vasculature. Additionally, PCCAs can be vaporized into echogenic microbubbles for diagnostic ultrasound imaging. Previous studies have demonstrated that the vaporization threshold of PCCAs is higher in vivo than...
This paper presents a comparative study on two analytical modelling techniques (i.e. Fourier analysis and Tooth Contour Method), applied to a benchmark topology of a linear permanent magnet synchronous motor (LPMSM). The investigated methods are used for obtaining the thrust force of a LPMSM with significantly reduced computation time (from the order of seconds to the order of milliseconds), compared...
This paper describes a preliminary development to an automatic tennis ball collecting machine. The framework adopts a roller to collect tennis balls when moving. Tennis balls are detected and tracked automatically by computer vision while hardware acceleration is used to improve efficiency. For navigation, fuzzy control and 6 ultrasonic sensors are used to avoid obstacles when approaching the targets...
Selective properties of resonant quasi-optical systems with periodical multi-row structures in millimeter wavelength range are described. The possibility of selection fluctuations in the volume of open resonator using double-row periodic elements was shown in the experiment at 70–80 GHz. Advantages and possibility of control the energy characteristics of such structures are also described. The obtained...
We analyze electrical processes in a complex system composed of a large number of elements using statistical computer simulations as a primary tool. This study is important as it helps to understand sophisticated phenomena that take place in various real-world systems such as nanocomposites or conductive polymers. Developed approach and software can be applied in environmental sciences, as mentioned...
Focused ultrasound (FUS) combined with microbubbles (MBs) has been shown to locally and temporarily open the blood-brain barrier (BBB). However, concurrent opening BBB (long pulse) and mapping the location of BBB opening (short pulse) by pulsed-wave excitation always conflicts. Previously proposed passive cavitation imaging in brain suffered from degraded axial resolution because of long driving pulse...
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