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HT-6M will be officially installed in Thailand in next few years. Some computational studies of possible experiments should be helpful in case of its experiment planning. The authors are interested on the scenario of macro-particle, i.e. dust and droplet, transporting in HT-6M. The study was carried out by the Dust and Droplet Tracking (DDT) code, consisting of basic equations and physical models involving with charging, heating, equation of motion and ablation on macro-particle in a tokamak plasma. DDT implemented a set of HT-6M core plasma profiles from the Transport Analyzing System for tokamaK (TASK) code and a set of HT-6M edge plasma profiles approximated from simple SOL model. We observed that relatively small macro-particles, i.e. initial sizes are less than 10−6 m, significantly involve with impurity generation near plasma facing components (PFCs). In addition, the 10−5-m macro-particles mostly ablate in SOL. The 10−3-m and 10−4-m macro-particles completely ablate if they transport towards core plasma, but some with the inclination with respect to the horizontal direction obtain longer lifetimes. Moreover, few of them can achieve abnormal high speed. The mechanism for this is the acceleration by rocket force due to partial ablation near core plasma.

The purpose of this study is to estimate thermal diffusivities of high thermal diffusivity bulk material as well as low thermal diffusivity bulk material by using many types of fluid such as Ethyl alcohol and water. This method is studied by measuring amplitude and phase of photodeflection signal in various frequency modulations. The experimental setup consists of two laser lines: 1) a pump laser beams through a modulator, varied frequency, controlled by lock-in amplifier and focused on sample surface by lens. 2) a probe laser which parallels with the sample surface and is perpendicular to the pump laser beam. The probe laser deflection signal is obtained by a position sensor which controlled by lock-in amplifier. Thermal diffusivity is calculated by measuring the amplitude and phase of the photodeflection signal and compared with the thermal diffusivity of a standard value. The thermal diffusivity of SGG agrees well with the literature but the thermal diffusivity of Cu is less than the literature value by a factor of ten. The experiment requires further improvement to measure the thermal diffusivity of Cu. However, we succeed in using ethyl alcohol as the coupling medium instead of CCl4 which is highly toxic.

The purpose of this paper is to develop a digital lock-in amplifier based on soundcard interface for undergraduate physics laboratory. Both series and parallel RLC circuit laboratory are tested because of its well-known, easy to understand and simple confirm. The sinusoidal signal at the frequency of 10 Hz – 15 kHz is generated to the circuits. The amplitude and phase of the voltage drop across the resistor, R are measured in 10 step decade. The signals from soundcard interface and lock-in amplifier are compared. The results give a good correlation. It indicates that the design digital lock-in amplifier is promising for undergraduate physic laboratory.

The thickness of coatings can be determined using the data measured by Modulated IR Radiometry for sets of coatings, produced under specific controlled conditions: – Keeping constant all deposition parameters except the deposition time, coatings of approximately constant thermal transport properties, but different thickness are produced. The modulated IR phase lag signals measured for the coatings are calibrated with the help of signals obtained for homogeneous opaque reference samples of smooth surface. Quantitative results for the thermal transport properties are obtained using the inverse solution of the 2-layer thermal wave problem by which direct relations are established between the relative extrema of the inverse calibrated thermal wave phase signals measured as a function of the heating modulation frequency and the thermal coating parameters, the ratio of the effusivities coating-to-substrate, the coating's thermal diffusion time, and the coating thickness. The coating thickness values obtained by Modulated IR Radiometry are compared with the values measured by standard microscopic methods, and relative errors of 3 – 4% have been found for the coating thickness of a set of TiCO coatings on steel, presented here as an example.