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Harvesting waste energy through thermoelectric has widely gained attention to aid green energy production. Current efforts are to take advantages of nanomaterials and nanosystems because of dramatic improvements in the performance. However, its cost-effectiveness in generating a 3D configuration for a large-area use is hindered by high production cost. To overcome the present challenges, we propose a flexible and lightweight thermoelectric developed on a melamine foam using a simple dip-dry technique to self-assemble conductive nanofilms in the scaffold. Different amounts of poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) conductive nanofilms were variedly fabricated in the foam due to altered amounts of sodium dodecyl sulfate (SDS) surfactant from 0 to 5 wt%. Together with experimental results, a theoretical model was constructed to predict thermal and electrical conductivities, indicating the strong influence of SDS to the electrical conductivity. As a result, the highest nanofilm formation in the foam structure is achieved by adding SDS at 3 wt%. The figure of merit (ZT) of thermoelectric foam is about 0.006–0.007. Our first device was also demonstrated with output voltage of 1.1 mV (ΔT = 40 K). The present study could provide the design and optimization of a hybrid thermoelectric that can act as a simultaneous thermal insulator and power generator.

Using a setup for testing a prototype for a satellite-borne cosmic-ray ion detector, we have operateda stack of scintillator and silicon detectors on top of the Princess Sirindhorn Neutron Monitor(PSNM), an 18-counter NM64 detector at 2560-m altitude at Doi Inthanon, Thailand. Monte Carlosimulations have indicated that about 15% of the neutron counts by PSNM are due to interactions(mostly in the lead producer) of GeV-range protons among the atmospheric secondary particlesfrom cosmic ray showers, which can be detected by the scintillator and silicon detectors. Detectionof incoming charged particles associated with neutron counts in the NM64 allows a measurementof the travel time distribution of such neutrons as they scatter and propagate through the NM64,processes that are nearly the same whether the interaction was initiated by an energetic proton (for15% of the count rate) or neutron (for 80% of the count rate). This travel time distribution underliesthe time delay distribution between successive neutron counts, from which we can determine theleader fraction (inverse multiplicity), which has been used to monitor Galactic cosmic ray spectralvariations over∼1-40 GV. In the present experiment we have measured both the coincidence rateof incident charged shower particles with neutron counts in the NM64 and the neutron travel timedistribution. We utilize these measurements to validate Monte Carlo simulations of atmosphericsecondary particle detection by the NM64 and the resulting yield functions used to interpret thecount rate and the leader fraction.

Thermoelectric generation capable of delivering reliable performance in the low-temperature range (

Thermoelectric generation capable of delivering reliable performance in the low-temperature range (150 °C) for large-scale deployment has been a challenge mainly due to limited properties of thermoelectric materials. However, realizing interdependence of topological insulators and thermoelectricity, a new research dimension on tailoring and using the topological-insulator boundary states for thermoelectric enhancement has emerged. Here, we demonstrate a promising hybrid nanowire of topological bismuth telluride (Bi

In conventional nuclear fuel rods for light-water reactors, a helium-filled as-fabricated gap between the fuel and the cladding inner surface accommodates fuel swelling and cladding creep down. Because helium exhibits a very low thermal conductivity, it results in a large temperature rise in the gap. Liquid metal (LM; 1/3 weight portion each of lead, tin, and bismuth) has been proposed to be a gap filler because of its high thermal conductivity (∼100 times that of He), low melting point (∼100 °C), and lack of chemical reactivity with UO 2 and water. With the presence of LM, the temperature drop across the gap is virtually eliminated and the fuel is operated at a lower temperature at the same power output, resulting in safer fuel, delayed fission gas release and prevention of massive secondary hydriding. During normal reactor operation, should an LM-bonded fuel rod failure occurs resulting in a discharge of liquid metal into the bottom of the reactor pressure vessel, it should not corrode stainless steel. An experiment was conducted to confirm that at 315 °C, LM in contact with 304 stainless steel in the PWR water chemistry environment for up to 30 days resulted in no observable corrosion. Moreover, during a hypothetical core-melt accident assuming that the liquid metal with elevated temperature between 1000 and 1600 °C is spread on a high-density concrete basement of the power plant, a small-scale experiment was performed to demonstrate that the LM-concrete interaction at 1000 °C for as long as 12 h resulted in no penetration. At 1200 °C for 5 h, the LM penetrated a distance of ∼1.3 cm, but the penetration appeared to stop. At 1400 °C the penetration rate was ∼0.7 cm/h. At 1600 °C, the penetration rate was ∼17 cm/h. No corrosion based on chemical reactions with high-density concrete occurred, and, hence, the only physical interaction between high-temperature LM and high-density concrete was from tiny cracks generated from thermal stress. Moreover, for as high as 1600 °C, the non-reactive LM was experimentally confirmed not to show any chemical reaction with air or moisture in the air. This experimental work confirmed the excellent compatibility behaviors between the LM as a PWR fuel gap filler and stainless steel and high-density concrete in the high-temperature regime.

The radiological hazards from natural radionuclides in soil at the border area between the northeast of Thailand and Laos were studied and evaluated. The 33 surface soil samples from Khong Chiam and Sirinthon districts in Ubon Ratchathani province were collected and measured the specific radioactivity (226Ra, 232Th and 40K). The radioactivity of all soil samples was analyzed from gamma ray spectrums using hyper-pure germanium detector. The results applied for calculating the radiological hazards which were radium equivalent activity (Raeq), absorbed dose rate (D), annual effective dose equivalent (AEDEout) and external hazard index (Hex). The experimental results obtained the radioactivity concentrations in a range of 10.64 to 46.67 Bqkg−1 with average value of 22.82 ± 3.59 Bqkg−1, 6.35 to 44.72 Bqkg−1 with average value of 15.49 ± 3.57 Bqkg−1 and 31.22 to 521.57 Bqkg−1 with average value of 130.44 ± 28.46 Bqkg−1 for 226Ra, 232Th and 40K, respectively. The calculation results of Raeq, D, AEDEout and Hex showed significantly lower than the radiological hazard levels which are recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation. The results of this study reveal that people can live and travel along the border area in the northeast of Thailand.

Roi Et is one of the provinces with rice farming and exported to many countries around the world. In order to assess the radiation risk index from Jasmine rice cultivated soils, 175 samples in Roi Et province were measured using the gamma ray spectrometry technique for estimating the natural radioactivity levels. The specific activity of 226Ra, 232Th and 40K was found from 7.14 to 29.02 Bq/kg, 7.24 to 33.40 Bq/kg and 18.17 to 129.65 Bq/kg with a mean value of 16.92 ± 1.16 Bq/kg, 16.99 ± 2.24 Bq/kg and 46.95 ± 6.79 Bq/kg, respectively. However, the values of radium equivalent activity (Raeq), the external hazard index (Hex), the gamma-absorbed dose rate (D) and the annual effective dose equivalent (AEDEout) were also calculated to evaluate radiological hazards. The average values of Raeq, Hex, D and AEDEout were found to be 44.83 Bq/kg, 0.12, 20.03 nGy/h and 0.02 mSv/y, respectively. From the results can demonstrate that the natural radioactivity from soil are not affect to population in the area, which the natural radioactivity levels and the radiation risk values of Roi Et soil samples are lower than the UNSCEAR values.

Cesium iodide doped with thallium (CsI:Tl) crystals was grown to develop the gamma-ray detectors by using low-cost raw materials. Effect of impurities on optical properties and radiation detection performance was investigated. By a modified homemade Bridgman–Stockbarger technique, CsI:Tl samples were grown in two levels of CsI and TlI reactant materials, i.e., having as a very high purity of 99.999 % and a high purity of 99.9 %. XRD measurements indicate CsI:Tl crystals having a good quality with a dominant (110) plane. Having a cubic structure, a lattice constant of CsI crystals of 0.4574 nm and a crystallite size of 43.539 nm were obtained. From the lower-purity raw materials, calcite was found in an orange crystal with a lattice constant of 0.4560 nm and a crystallite size of 43.089 nm. By PL measurements, the optical properties of the CsI:Tl crystals were analyzed. ~540-nm-wavelength PL peak was observed from the colorless high-purity crystal, and ~600-nm-wavelength PL peak was observed from the orange crystal. The brighter PL emission was obtained from the orange crystals suggesting impurities. CsI:Tl surface morphology by SEM exhibited a smooth surface with some parallel crystal facets. For electrical properties of high-quality CsI:Tl crystals, the electrical resistances were 230 ± 16 MΩ in cross-sectional direction and 714 ± 136 MΩ in vertical direction with respect to more homogeneous crystal quality in cross-sectional direction than that in vertical direction. TEM measurement was applied to evaluate the microstructure of colorless CsI:Tl crystal with different patterns of a cubic structure. Both CsI:Tl crystals show good efficiencies and good resolutions. Maintaining the same electronic conditions and amplifications, the colorless CsI:Tl scintillators represented a higher detection efficiency at 122 keV of Co-57 of 78.4 % and the energy resolution of 23.3 % compared to the detection efficiency of 75.9 % and the energy resolution of 34.6 % of the orange scintillators. In summary, the unintended impurity as calcite in low-cost CsI:Tl scintillators was found to enhance PL emission but shift the PL wavelength. However, efficiency of radiation detection is slightly lower. By coupling with a suitable PMT, the radiation detection efficiency of low-cost CsI:Tl scintillators can be improved. From these valuable results, growing new ternary materials as CsCaI2 or CsI:Ca or Ca-codoped CsI:Tl scintillators could be one of the promising approaches to achieve highly efficient and low-cost radiation detectors with the optimization of the crystal growth conditions in the future.

A simple high-temperature furnace with two independent heating zones was developed based on the moving-temperature-gradient concept with an operating range of 400 to 1,200°C. Programmable temperature reduction rates of the two heating zones are independently controlled in a closed chamber for better thermal stability throughout the growth zone. In order to eliminate the driving mechanism and reduce subtle vibration, which could adversely affect crystal quality, the charge crucible and furnace are made stationary during the growth process. Measurement results of temperature distributions of gradient drifting rates at various positions along the growth zone are presented. The growth of CsI(Tl) scintillation crystals prepared from a mixture of 99.9% pure CsI powder and Tl powder, using the growth rate of 1 mm/h, temperature gradient of 25.5°C/cm, and temperature gradient drift rate of 2.5°C/h, was achieved with crystal sizes of 10 and 22mm diameter, both 70mm in length. Test results of gamma energy resolutio...