Tsing-Tshih Tsung

Aqueous Aluminum Nanofluid Combustion in Diesel Fuel

This paper presents a significant chemical reaction of hydrogen combustion during aqueous aluminum nanofluid combustion in diesel fuel. The results show that hydrogen burns in a diesel engine in the presence of an active aqueous aluminum nanofluid. The nano particles are made by applying a plasma arc to aluminum nanopowder submerged in water. The average diameter of the aluminum nanoparticles is about 40–60 nm and they are covered with thin layers of aluminum oxide due to the high oxidation activity of pure aluminum. This provides a large contact surface area with water and high activity for the decomposition of hydrogen from water during the combustion process. During combustion the alumina serves as a catalyst and the coated aluminum nanoparticles are denuded and decompose the water to yield the hydrogen. The combustion of the diesel fuel mixed with aqueous aluminum nanofluid shows the following phenomena: total combustion heat increases while the concentration of smoke and nitrous oxide in the exhaust emission from diesel engine are decreased.

Producing Aluminum-oxide Brake Nanofluids Using Plasma Charging System

This study examines the characteristics of Aluminum-oxide brake nanofluids (AOBN) manufactured by a home-made machine, the plasma arc system. The plasma electric arc welding machine was specially modified to be a nanofluid production system in the experiment. Argon was chosen to be the plasma gas because it can be ionized very easily and needs only lower voltage to keep the production of plasma electric arcs continuous. The aluminum bulk specimen is then mixed with DOT3 break fluid. The AOBN thus obtained shows a higher boiling, higher viscosity and higher conductivity. Furthermore, they are affected by the synthesizing parameters such as cooling liquid temperature and vacuum pressure. The confirmed appearance of nanoparticles was determined by Transmission Electron Microscopy (TEM) and X-RAY. This study revealed that a home made plasma arc machine can produce AOBN which surpasses the boiling point to reduce the occurrence of vaporlock, higher viscosity, higher conductivity and circle geometry common to the superior performance of brake nanofluids.

Evaluation of dynamic performance of pressure sensors using a pressure square-like wave generator

In this study, we measured the dynamic characteristics of pressure sensors using a pressure square-like wave generator (PSWG). With high excitation energy, the PSWG can measure dynamic pressure and work more effectively in a high frequency range. Under the same experimental parameters (10 bar, 600 Hz), the performance of six pressure sensors of dissimilar design and structure was evaluated. The experimental results indicate that they all exhibited extremely different dynamic characteristics. The dynamic pressure sensors based on quartz plates and crystals possess larger overshoot, greater gain margin and shorter rise time in comparison with other sensors based on strain gauge and piezoresistive materials. Compared with other traditional methods, such as the hydraulic control method, the PSWG proves to be superior in that it can be employed to evaluate the dynamic performances of pressure sensors at high frequency of above 10 kHz.

A preliminary report of a disposable electrical non-fiberoptic endoscope in thoracoscopic surgery.

PURPOSE Conventional thoracoscopic surgery requires a camera connected to optic fibers and rigid rod lens to ensure the provision of adequate light and quality of real-time images in the operative field. However, the camera, the connected optic fibers and rigid rod lens are not disposable due to cost, which is a concern as regards potential contamination of patients. To decrease such contamination, we designed a disposable device of extremely low cost which we tested in thoracoscopic surgery in animals. DESCRIPTION A complementary metal-oxide-semiconductor is used for obtaining real-time image at a refresh rate of 30 frames per second. A circumferential light was added by a light emitting diode. We connected wires to a universal serial bus adapter, with which the device can negotiate with a computer so as to control signal retrieval and adjustment of the light as well as focus. The device was designed to be as compact as possible. The contour resembled a conventional thoracoscope, but with no optic fibers and rigid rod lens included. EVALUATION We used the devices to perform routine thoracoscopic surgical procedures, including wedge resection of the lung, lobectomy, esophagectomy, pericardiotomy and pleural biopsy in two 40-kg pigs under general anesthesia. The operating techniques were not altered while using this device. CONCLUSION This disposable, electrical non-fiberoptic endoscope has the potential to be easily and safely used in routine thoracoscopic surgery at a minimal cost. Further clinical evaluation will be required to demonstrate the utility in human patients.

Fabrication and characterization of CuO nanorods by a submerged arc nanoparticle synthesis system

The purpose of this study is to investigate an innovative nanorod preparation method, the submerged arc nanoparticle synthesis system. The key parameters such as discharge current, breakdown voltage, pulse duration, and temperature of the dielectric liquid are carefully analyzed in order to obtain more uniform nanorods. The prepared nanorods were systematically characterized by x-ray diffraction, transmission electron microscopy, selected-area electron diffraction, x-ray photoelectron spectroscopy, and the ultraviolet-visible absorption spectrum. The results showed that the CuO nanorods had a diameter of 30–50nm and a longitudinal length of up to 1–2μm. A possible preparation mechanism was also discussed for the growth of the CuO nanorods.

Spontaneous empyema necessitatis caused by Aspergillus fumigatus in an immunocompetent patient.

We present a rare case of spontaneous empyema necessitatis caused by Aspergillus fumigatus infection.

Motion artifacts in CT scans: a study by computer simulation and mechanical phantom

Computed tomography (CT) is one of the most important tools in the diagnosis of thoracic tumors. However, during the scanning process, respiratory motion causes changes in the position and shape of the tumor, creating motion artifacts in the CT scan. This can lead to misdiagnosis of the size and position of the tumor, and can affect the effectiveness of treatment. This study develops a computer model of the movement of the thorax, and simulates the movement of a lung tumor caused by breathing during a CT scan. We show that adjusting the CT slice thickness is sufficient to determine the center of displacement and maximum displacement of a tumor during normal breathing. This model can be applied in the clinical diagnostic use of CT equipment. It will assist in finding the position of lung tumors from motion artifacts in CT scans. The target margin for treatment can thus be defined more accurately, so that appropriate doses of radiation can be applied to the target area, and irradiation of healthy tissue avoided.

Temperature Effect on the Stability of CuO Nanofluids Based on Measured Particle Distribution

This study aims to investigate the temperature effect on particle size of copper oxide nanofluid produced under optimal parameters of the Arc Spray Nanoparticle Synthesis System (ASNSS) developed in this research. The purpose is to understand the aggregation feature of copper oxide nanofluid in a higher-than-room-temperature environment and to analyze its size change and the motion behavior of suspended nanoparticles. This study employs an ambient temperature controller to maintain the environment temperature within the scope of normal fluid work temperature to obtain data on the change in suspended particles of copper oxide nanofluid under varying temperatures and through change of time. Experimental result shows that the particle size distribution of copper oxide nanofluid changes when the temperature rises due to the slight absorption and aggregation phenomena between particles, and that the change in environmental temperature can accelerate the aggregation of copper oxide nanofluid, which can affect its stability in application. However, the change in particle size distribution will gradually stabilize for a longer duration of constant temperature.

Analysis of dynamic characteristics of pressure sensors using square pressure wave theory and system identification

Most analyses on pressure sensors focus mainly on their static characteristics, while their dynamic characteristics have rarely been explored. In the field of applied engineering, a pressure sensor with a quick response rate and high stability is required to reflect the dynamic behaviour of the hydraulic system. This study developed a square pressure wave generator to replace the traditional directional control valve. The developed generator can generate a square pressure wave of as high as 2 kHz and can achieve high-frequency switching by utilizing the differential principle through a series of mechanical rotations between the revolving spindle and revolving ring. The square pressure wave generated is input into the hydraulic system while the output voltage signals given by the pressure sensor can be analysed by spectrum analysis and system identification to obtain various dynamic characteristics of the pressure sensor, including transfer function, natural resonance frequency and damping ratio.

Dynamic Performance Measurement of Proximity Sensors for a Mobile Robot

Knowledge about dynamic performance is very important for a control system. When carrying out static performance of a mobile robot, the sensing distance of various materials is established. However, based solely on this factor for controlling the mobile is not exact. Because in fact, many factors will influence to mobile robot controlling, they are determined by the relationship between the physical quantity in the measurement. Through a detailed study of theoretical knowledge and by some empirical methods of the conveyor system, we can determine the relationship of the dynamic parameters, such as: velocity, sensing distance, dimension of material, thickness of material, and so on. Experimental results demonstrate that the shape as the output signal depends on the type of sensor being used. To research the scope of the mobile robot, an analog proximity sensor is optimal, and to identify the output signal ON or OFF, the selection of digital sensor is better than an analog sensor. This is as a basis to improve the theoretical knowledge of mobile robot controller through the proximity sensor. Simultaneously, with these results, mobile robot is able to sense its world and change its behaviour on that basis.