bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement of electrocaloric properties of P(VDF-HFP)/GNPs composites for refrigerator cooling
Authors: Permana A A , Ngamdee W , Putson C
Published: December 2019

Electrocaloric effect originally comes from the cross-coupling between temperature and polarization of dielectric materials. Poly (vinylidene fluoride)/P(VDF) and its copolymers exhibit high displacement and dielectric properties among all ferroelectric polymers with additional advantages like lightweight, flexible and low cost compared with other dielectric materials. Moreover, poly (vinylidene fluoride hexafluoroprophylene)/P(VDF-HFP) copolymers shows highest breakdown strength. P(VDF-HFP) copolymers was used as the main matrix with graphene nanoplatelets (GNPs) conducting materials as nanofillers. The P/GNPs composites thin films were prepared by solution casting method with the final thickness of 30 +/- 5 µm using N, N-dimethylformamide (DMF) as solvents. The GNPs content was varied of 0, 1, 2, 3, 4 and 5% by weight. The dielectric and electrical properties were measured by LCR meter with various frequency of 1 to 100 kHz. The structure and crystallinity were observed by XRD and DSC. The polarization as a function of external electric field was investigated by P-E loop instrument in 40 MV/m with varying temperature from room temperature to 140 °C. Furthermore, electrocaloric effect was measured by indirect method by calculating adiabatic temperature change (ΔT) with help of Maxwell relation. The experimental results show that dielectric constant of P/GNPs composites was increased by increasing the GNPs content but dielectric loss is kept constant with low loading, far away from the percolation threshold. Moreover, the ΔT of the P/GNPs composites is higher than the pure P(VDF-HFP) copolymers that leads to higher electrocaloric effect. The Increasement of the ΔT of P/GNPs composites will be discussed based on their microstructure, phase transition and crystallinity. As conclusion, adding GNPs nanofillers to P(VDF-HFP) matrix can improve dielectric constant as well as electrocaloric properties which has capability for refrigeration cooling system.
Empirical model of magnetic field line spreading in isotropic turbulence with zero mean field
Authors: Sonsrettee Wirin
Published: December 2019

In many cases, the random walk of magnetic field line in isotropic turbulence with zero mean field is appropriated to describe the transport of energetic particles in the interstellar medium of our Galaxy. To understand the transport, our previous work determined the asymptotic field line diffusion coefficient by using Corrsin’s hypothesis and presumed models of field line spreading. Two of those models of field line spreading are the diffusive decorrelation (DD) model and the random ballistic decorrelation (RBD) model. The variances of the field line displacement in, say, the x direction for the DD and RBD models are assumed as

σ
x
2

=
2
D
|
Δ
τ
|
=
2

(

λ
∼

/

3

)

b
|
Δ
τ
|

and

σ
x
2

=

(

1
/
3

)

b
2

|
Δ
τ

|
2

, respectively. τ is the field line displacement parameter defined as dτ = ds/B, where s is the arc length along the field line and B is the magnitude of the total magnetic field. D is the asymptotic diffusion coefficient, b is the rms magnetic fluctuation and

λ
∼

is the ultrascale. Comparing with simulation results, the DD and RBD models predict the D values with ⩽ 15% error and ⩽ 21% error, respectively. To improve the theoretical model empirically, in this work, we assume that the proper model the variance is

σ
x
2

=
β

(

b
|
Δ
τ
|

)

α

, where β is a proportional constant and α is an exponent. We extrapolate β with the proportional constants of DD and RBD models. Comparing with the simulation result of Kolmogorov turbulence, we obtain α = 0.8694. To test validity of the model, we compare the theoretical results of

σ
x
2

=
β

(

b
|
Δ
τ
|

)

0.8694

(formulated from Kolmogorov turbulence) with simulation results of two other turbulences: IroshnikovKraichnan turbulence and weak turbulence. The theoretical results of the empirical model match the computer simulation results very well (with ⩽ 0.9% error).
Effects of anti-solvent in the two-step fabrication of absorber layer in perovskite solar cells
Authors: Butsriruk K , Taychatanapat T , Chatraphorn S
Published: December 2019

Hybrid organic-inorganic perovskite materials, e.g., CH3NH3PbI3 (MAPbI3) have been used as photon absorber layer in the emerging solar cell technology. The two-step spin coating technique has been employed to fabricate the absorber films. It has been found that the use of anti-solvents plays a crucial role on the growth of the perovskite crystals. Chlorobenzene (CB) and Toluene (TO) were chosen as the anti-solvents that were applied after spin-coating of Methylammonium Iodide (MAI) solution in the second step of the two-step process. The amount and the elapsed time of the application of anti-solvents after spinning MAI solution were varied and studied for the crystal growth of perovskite films as well as the performance of the perovskite solar cells (PSCs). It was found that 50 ml of CB applied at 5 s after spinning MAI solution yielded the best solar cells parameters with the best efficiency of 16.8 %.
Non-invasive microwave sensor for the detection of the cell culture medium residues
Authors: Wanthong A , Harnsoongnoen S
Published: December 2019

A metallic circular tapped split ring resonator (CT-SRR) coupled with coplanar waveguide (CPW) are designed and fabricated for the non-invasive measurement of the cell (fibroblasts and adipocytes) culture medium residues (MRs), comprising remaining nutrients (glucose and electrolytes), serum, and other substances following cell cultures. Pre-culturing MRs were prepared with the same standard formulas and divided into four cases, i) pre - MRs with serum, ii) pre-MRs with serum and herb extract, iii) pre-MRs with serum and hormones and iv) pre-MRs with serum, hormones and herb extract. The four cases of culturing MR preparations are measured and analyzed by the proposed microwave sensor through transmission coefficient (S21) in the frequency range from 1.5 GHz – 2.5 GHz. The experimental results show that the highest of S21 and cells fat accumulation activity in case (iv) which related to the lowest remaining nutrients. The order amplitude of S21 at 1.96 GHz with material under tests (MUTs) at 1.96 GHz as follows: case (iv) > case (ii) > case (i) > case (iii) > DI water > air. The results demonstrate the feasibility of a non-invasive microwave based biochemistry sensor technology.
Effects of few optical cycles approximation to spectral broadening generated in two-zero dispersion wavelengths fibers
Authors: Louicharoen Phunsakorn , Naiam Krittapak , Tianprateep Montian , Wannadelok Orapin
Published: December 2019

It is both experimentally and numerically confirmed that Supercontinuum can be generated by pumping a few-tens-femtoseconds short pulse in anomalous dispersion region of a two zero-dispersion wavelengths (ZDW) fiber, such as, photonic crystal fiber. In numerical method, a well-known slowly varying envelope approximation (SVEA) has always been used to illustrate how the short pulse expands to a broadband spectrum in two-ZDWs fiber. But, the limit of SVEA is that it can only be applied for the short pulse, which its temporal envelope changes slowly comparing with its optical cycle. However, a few optical cycles short pulse is not fit with the condition of the SVEA approximation. In this report, another model, namely slowly evolving wave approximation (SEWA), is applied for numerical demonstration of supercontinuum generated by pumping the few optical cycles short pulse in two-ZDWs fiber. According to our simulation, under SEWA the final spectral width of the very short input pulse in the two-ZDWs fiber is between about 500 - 2000 nm, even the center wavelength of input pulse is near second-ZDW of fiber. Moreover, other effects of these two approximations since the center wavelength of the very short input pulse is close to both upper and lower ZDWs of the fiber in the same fiber’s length are also compared in our presentation.
Comparing performance of multi-frequency bands Occam’s receiver function inversion to standard linearized receiver function inversion
Authors: Trinakoon S , Vachiratianchai C , Amatykul P , Siripunvaraporn W , Noisagool S
Published: December 2019

Receiver function (RF) is a characterized waveform that sensitive to the sub-surface velocity structure near the seismic station. In the geophysical problem, an inversion scheme has been used for determining the structure model that corresponded to the observed data. Because RF inversion is a non-linear problem, the standard method such as linearized inversion suffered in the non-uniqueness of the results. Thus, using a stochastic optimization algorithm (e.g. Monte Carlo or Generic Algorithm) is the most interesting trend for solving the problem. However, their computation cost is high and the efficiency is strongly depended on user setting. In this work, Occam’s inversion algorithm, which is popular in the electromagnetic method, and multi-frequency bands receiver function have been integrated to improve the efficiency of receiver function inversion. The propagation method has been applied for the calculation of seismogram in this work. The synthetic cases, which are thin low velocity zone model (TLVZ), broad low velocity zone model (BLVZ), thin high velocity zone model (THVZ) and broad high velocity zone model (BHVZ), were used to compare the performance of this newly implemented algorithm and the standard linearized inversion. Single frequency band (SFO) and multi-frequency bands Occam’s inversion (MFO) have been tested for each case. For, TLVZ, THVZ and BHVZ, the MFO inversion provided better fitting results than SFO in most cases. Comparing to linearized inversion of CPS330, the MFO results still provide better performance. For the smooth low velocity structure in BLVZ model, both linearized and MFO can recover a significant structure of the true model. More concisely, the linearized inversion can recover the absolute velocity of the true model better than MFO. By the way, the MFO provides the best data fitting for the BLVZ. In summary, the MFO receiver function inversion that implemented in this study provides a new improved tool for a seismologist to investigating the subsurface structure.
Preliminary testing for reduction of insertion torque of orthodontic mini-screw implant using diamond-like carbon films
Authors: Jongwannasiri C , Charasseangpaisarn T , Watanabe S
Published: December 2019

Nowadays, titanium alloy is widely used as orthodontic mini-screw implants due to its suitable mechanical properties and excellence in biocompatibility. However, the excessive torques applied during the insertion of orthodontic mini-screw implant can cause necrosis of the surrounding bone. In this article, the insertion torque of orthodontic mini-screw implants is aimed to reduce during treatment by means of surface coating. The three types of coatings, namely, DLC, F-DLC 2:1 and Si-DLC 2:1 coated on orthodontic mini-screw implants were chosen to take into account the insertion torque values compared with uncoated surface. The friction behaviors of the films in ambient air and dry air were assessed using ball-on-disk friction testing. Cytotoxicity tests were performed using MTT assay. The insertion torque values were measured by physiodispenser. The results indicated that, both measured in ambient air and dry air, the addition of F into the DLC films slightly influenced the friction coefficients, while doping with Si strongly influenced the films. These films also exhibited less cytotoxicity on their surfaces. Furthermore, the insertion torque values decreased when coated orthodontic mini-screw implants with F-DLC 2:1 and Si-DLC 2:1 films. Therefore, the F-DLC 2:1 and Si-DLC 2:1 films can be considered to apply on orthodontic mini-screw implant for reducing the insertion torque.
Constraints on dark matter annihilation with electron spectrum from VERITAS
Authors: Khan Cantlay Brandon , Wechakama Maneenate
Published: December 2019

Cosmic-ray electrons (and positrons) can be used to probe self-annihilation or decay of dark matter particles. We have used spectrum of high energy cosmic-ray electrons between 300 GeV and 5 TeV measured by Very Energetic Radiation Imaging Telescope Array System (VERITAS) to constrain dark matter annihilation cross-section in the solar neighbourhood. A diffusion-loss equation with a canonical model has been used as a spectrum model function by assuming a NFW profile for the Milky Way halo. We have considered cosmic-ray electrons as products of annihilation of heavy dark matter particles (GeV -TeV). During the propagation through interstellar medium, the cosmic-ray electrons lose their energy due to synchrotron radiation, inverse-Compton scattering and ionization processes.
Low-energy heavy-ion beam induced high-yield mutation breeding of Thai jasmine rice (Oryza sativa L. cv. KDML 105)
Authors: Phanchaisri B , Techarang J , Semsang N , Yu L D
Published: December 2019

Thai jasmine rice was improved by low-energy heavy-ion beam induced mutation breeding for high yields. Seeds of Thai rice KDML105 and its ion-beam-induced primary mutant BKOS6 were bombarded by mixed atomic and molecular nitrogen ions accelerated by tens kV in a home-developed high-current ion implanter. Both phenotypes and genotypes of induced mutants were investigated. In M1 generation, more than a hundred plants with the photoperiod-insensitivity potential were obtained. In the subsequent generations, tens of rice mutants with a broad spectrum of phenotypic variations dominantly supporting the high yield potential were selected and studied for the mutation stability till M5 generation. The mutants possessed not only high crop yields but also other properties improved or altered in the grains. DNA fingerprinting analysis revealed polymorphisms in the mutants distinguished from that of KDML105. The cDNA fingerprinting investigation indicated four additional fragments in the mutant profiles encoding proteins which could be involved in the high yield characteristics of the mutants.
The analysis of the perforation of the bullet 11 mm. on the metal sheet
Authors: Eksinitkun G , Phungyimnoi N , Poogun S
Published: December 2019

The bullet hole traces from both entrance and exit at the crime scene are important data which can be used in the investigation. Most of the analytical investigation will be mostly considerably on the physical appearance e.g. tear, traces of gunshot, the size of the entrance and exit bullet holes. The purpose of this research was to study the pattern and the difference of marks on the metal target caused by the collision of gunshots using 4 types labeled as A is Full Metal Jacketed (FMJ) 135 gr. of Thai Arms., B is Jacketed Hollow Point (JHP) 230 gr., C is Full Metal Jacketed (FMJ) 230 gr. and D is Lead Semi Wad Cutter (LSWC) 200 gr. all of Bullet Master, shot from a Colt Gold Cup 11 mm caliber at 7 different distances as 0.00, 0.15, 0.50, 1.00, 1.50, 2.00 and 2.50 meters to records a diameter of bullet hole. In this experiment, the shot at the close range could be seen most clearly physically. On the metal target, ring of the black gunshot residue around the collapse entrance of bullet holes and a tear at the exit of the bullet was appeared. The physical properties of bullet hole on the metal sheet of each bullet type are different that can basically inform about type of bullet (p < 0.05), at the 95% confidence level but the size of bullet hole can’t use for identity shooting distance.
Development of DAS for prototype of brinell-macro-hardness tester using triplex of force-resistive-sensors manipulated by raspberry pi 3 model B
Authors: Muangma Rakdiaw , Supawan Kanitta , Thepnurat Meechai , Saphet Parinya , Tong-on Anusorn
Published: December 2019

The resulting of advanced technology, the size of Personal Computer (PC) was reduced into the same size as cigarette box. Thus, the Brinell-macro-hardness tester used Raspberry Pi 3 (RPi3) Model B to acted as the Data Acquisition System (DAS) or the mini-PC which used for measuring of Active-Weight-Loading (AWL) parameters. This DAS used the triplex of force-resistive sensors equipped using IC-MCP3008 and interfaced with RPi3. This IC was used to converse the analogue signal of AWL to 10 bits of the digital signal, and then, the digitalized-data were transferred through the Serial Peripheral Interface (SPI) of RPi3, respectively. In the acquisition procedure, the real-time of measuring-data were revealed using the Graphical User Interface (GUI) which developed using the python language version 2.7. Consequently, it was perceived that this DAS can be fabricated using simple and low-cost design. Therefore, this contrivance can be regularly used for AWL measurement which is the one part of Brinell hardness measurement. Finally, the fabrication of electronic parts and software interfacing which manipulated using RPi3 were presented in the discussion section.
Thai national telescope studies of ultraluminous X-ray sources
Authors: Thongpoyai K , Luangtip W , Sawangwit U , Roberts T P , Komonjinda S , Dhillon V S , Marsh T R
Published: December 2019

Ultraluminous X-ray sources (ULXs) are extra-galactic, non-nuclear sources with X-ray luminosity in excess of 1039 erg s–1. It has been thought that the majority of ULX populations are stellar-mass objects accreting matter at a super-Eddington rate. Although ULX studies are often focused in the X-ray regime, this work studied the ULXs in the optical regime, identified as the ULX counterparts (CTPs). The optical variability of nine CTPs were observed using the 2.4-m Thai National Telescope. Out of the nine ULXs, we detected three ULXs exhibiting strong variability up to ∼1 magnitude, suggesting that the CTP light does not come from the donor star’s emission. The paper discusses the physical origins of the variability which potentially explain the observed light curves.
Prediction of the bitterness of pharmaceutical drugs using a taste sensor with representative group data by the center of mass
Authors: Pradhan Sarika , Jityen Arthit , Osotchan Tanakorn
Published: December 2019

The purpose of this study is to analyze the effectiveness of taste sensing system to predict the bitterness of six commercial pharmaceutical drugs including amoxicillin, paracetamol, phenylephrine, cetirizine, quinine, and ranitidine. The taste sensing system consists of Ag/AgCl as a reference electrode, platinum rod as a counter electrode and modified electrodes as working electrodes. The four different working electrodes had been fabricated by using CoPc, MnPc, FePc and ZnPc mixed with multi-wall carbon nanotube, respectively. The cyclic voltammogram of 1 mM of pharmaceutical samples was run at a scan rate of 0.09 V/s, with the potential range between -1 and 1 V. The wavelet analysis was used to reduce and extract the main feature of data. By using coordinates in the two-dimensional space of principal component analysis, the Euclidean distance of each sample was calculated with respect to coordinates of Acesulfame K. The coordinate of Acesulfame K was used as the point of reference. According to machine learning, the k-mean clustering and center of mass approach were used to locate the centroid of coordinates of the samples in the principal component analyses. The calculated Euclidean distances from the centroid point were directly associated with the intensity of bitterness of the samples. To further validated the ranking of bitterness drawn from taste sensing system, the data were correlated with the bitterness ranking drawn from gustatory sensation test. The good correlation was obtained between machine and human sensory ranking.
Circumbinary planet study around NSVS 14256825
Authors: Sappankum P , Komonjinda S , Awiphan S , Rattanamala R , Dhillon V S , Marsh T R , Suphapolthaworn S
Published: December 2019

The period variability of (O-C) diagram of an eclipsing binary, NSVS 14256825, which is composed of a hot subdwarf type OB star (sdOB) and a main-sequence low-mass type M star (dM) in close orbit with period P=0.110374 days, previously showed sinusoidal signal cause by the light travel time effects. This signal can be caused by the presence of third bodies. We re-examined (O-C) diagram of the system. We combined eclipse timings from published data and the data taken from ULTRASPEC at 2.4 m at Thai National Telescope on November 2018. From the fitting model, the parameters of the third body in NSVS 14256825 system are obtained.
DIY small scale resonance tube for measuring the speed of sound in air
Authors: Wijitwongwan P , Wuttiprom S
Published: December 2019

This research invented a small scale with no cost experimental set to determine the speed of sound in the air by resonance method. Equipment consisted of a bubble tea straw with label measuring scale, a full plastic water bottle and the n-Track Tuner (iOS) or Guitar Tuner (Android) application for generating sound waves. Sound waves were sent down a bubble tea straw filled with an air. The waves reflected back up the straw from a water surface and interfered with the waves traveling downward. By properly adjusting the water level, a resonance condition could be established. By knowing the frequency of the sound wave and the position of the water level for two different resonant lengths, the speed at which sound waves travel through the air was found. In this experiment, the frequency was specified 1, 500 Hz at 24.00 °C, 26.00 °C and 30.00 °C respectively. The sound speed which was calculated was 345.0, 347.0 and 349.0 m/s respectively. The standard value of sound speed at the same temperature was 345.4, 346.6 and 349.0 m/s respectively. The percent error value of the sound speed was calculated to compare with the standard value of sound speeds was 0.1%, 0.1% and 0.0% respectively. This an experiment was effective and could be efficiently used in educational physics. Moreover, it is easy to use, low cost, and portable. Students can also prepare the equipments themselves.
Macroscopic model for multi-anticipation self-driving cars
Authors: Nateeboon T , Termsaithong T , Hirunsirisawat E
Published: December 2019

Self-driving cars technology and vehicle connectivity enable self-driving cars to precisely receive information of many cars leading them. By multi-anticipation, a flow of self-driving car is proved to be more stable than without multi-anticipation. The instability of traffic flow can cause a traffic jam as a little velocity fluctuation is amplified. In this work, we discuss the macroscopic effect of parameters in the microscopic model for a self-driving car. Those parameters are the number of the vehicle the car anticipate (field size) and weight for anticipation with the leadings (strength factor). The macroscopic model is derived from the microscopic model. We obtained a partial derivative equation that describe how the velocity fluctuation change through time. According to our model, these two variables play a crucial role in the traffic flow harmonization. Comparison between each model was carried out and discussed.
Josephson current in silicene-based SBS Josephson junction: Effect of perpendicular electric field
Authors: Suwannasit T
Published: December 2019

The Josephson effect in silicene-based superconductor/barrier/superconductor (SBS) junction is theoretically investigated by the Dirac-Bogoliubov-de Gennes equation, where superconductors are the proximity effect through superconducting gates and a thick barrier is the presence of a perpendicular electric field and an electrostatic gate. The influence of electric field is used for inducing a bandgap in monolayer silicene. We find that the Josephson current is controlled by the effect of electric field EZ. The behavior of critical current IC
on the perpendicular electric fields is linear dependence at case of VG = 0. The gate control of electric field is led to the linear slope d(IC
/I
0)/dlEZ
as revealed to 1/EF
and –1/EF
in the different direction of electric fields. In addition, the linear dependence of the Josephson current is considered by the electrostatic gate VG
. The appearance of linear effect in the tunable barrier is near the bottom of conduction band and the top of valence band. These results are suitable for controlling the Josephson current in silicene-based junction.
Numerical study of radial force and equilibrium position of microscale spherical particle under the effect of inertial focusing in 2D microchannel
Authors: Natyanun S , Pussadee N
Published: December 2019

Particle inertial focusing is a passive phenomenon at which a particle is acted upon by interaction with fluid and a channel wall, causing it to align at a certain distance from the channel wall called the equilibrium position as all transverse forces balance. In this work, numerical simulations using the finite element method were conducted in order to evaluate the forces acting on a spherical particle under Poiseuille flow in a 2D microchannel. Various fluid and particle parameters investigated include fluid density, viscosity, mean flow velocity, particle and channel dimensions. The calculated particle’s equilibrium position in relation to each individual parameter is found to be proportional to the square of mean fluid velocity and fluid density, and the cube of particle size while inversely proportional to channel half-width and the square of fluid viscosity.
Effect of blade number and angle on the characteristics of the savonius type wind turbine
Authors: Chaichana T , Thongdee S
Published: December 2019

The savonius type vertical axis wind turbine can be operated in all wind directions, is low cut in speed and high in torque. Therefore, it is a potential source of energy in low wind areas. This research aimed to compare the performance of H-Savonius vertical axis wind turbine using blades numbers and blades angle. The turbine containing the blades numbers 4, 6, 8, 12, 16 and 18 with the blades angle being at -15°, -5°, 0°, 5° and 15°, respectively. Tests were undertaken at open type circuit wind tunnel. The results showed that the maximum power coefficient of the wind turbine at 16 blades and angle of 5° with an average of 0.26 which had 4.5 % increase in power compared to that of turbines the baseline. Finally, the cut in wind speed and the rev up time was 2.32 m/s and 25 s, respectively.
Design and development of rotary magnetic refrigeration prototype with active magnetic regeneration system
Authors: Lupponglung V , Kanluang T , Panjatawakup P , Hanlamyuang Y , Matan K , Techapiesancharoenkij R
Published: December 2019

In the field of cooling system, a traditional vapor compression (VC) technology has been used over long time. The VC cooling is simple and cost effective, however, it raises global warming concern due to its relatively low energy efficiency and usage of ozone depletion substances. Magnetic refrigeration (MR) has been proposed as a potential cooling technology that can replace the VC cooling. MR can potentially be operated with efficiency closer to the theoretical efficiency, without using environmentally-harmful refrigerants. In the MR system, a magnetocaloric material (MCM) with magnetocaloric effect (MCE) is used as a refrigerant. The temperature of MCM can be increased and decreased under adiabatic magnetization and demagnetization, respectively. Water/ethylene glycol can be used as heat-exchanging fluid. In this work, a rotary MR prototype was designed and built. The prototype consists of the following main systems: 1. Flow distribution system, 2. Rotary magnetic field generator 3. Mechanic system, and 4. Temperature and pressure sensor system. Four beds of magnetocaloric gadolinium (Gd) particulates were used as an active magnetic regenerative cooling media. Fluid flow was controlled by pneumatic pump and solenoid valves. Rotary magnetic field generator was designed and built with maximum and minimum fields of 0.65 and 0 T, respectively. The overall setup and preliminary study showed that the pressure drop across the system was 2 bar when the flow rate was only 0.5 L/min. Increasing flow rate further resulted in too high pressure drop causing the MCM bed to swell. Therefore, the flow rate was limited to 0.5 L/min resulting in insufficient heat transfer rate by the slow heat exchange fluid flow. Consequently, the maximum temperature span was measured to be 0.5 K. The prototype must be improved to drive flow rate higher and to reduce the pressure drop of the system.
Impedance measurement system simulation for trapped cell model in various microwell geometries
Authors: Sanin Sorawit , Pakpum Chupong , Pussadee Nirut
Published: December 2019

Single cell analysis is a measurement or detection of individual cell properties and responses. The method is of significance due to stimulated responses of any individual cell are different depending on their morphology and functionality. Therefore, detected properties from a group of cells cannot be used to represent that of the individual cell. Since cells can move freely in a microfluidic system, a trap must be added to the system to fix the cell position at the detection region for long period observation and assay. One of the most popular used cell trap in the biomedical field is a microwell array. A sensitive technique for measuring single cell properties is an impedance measurement, in which small change in electrical properties of the cell and the surrounding medium between excitation and pick-up electrodes is recorded. However, the microwell placed between two electrodes acts as an electrical insulator to reduce the signal passing through the system. This paper focuses on the effect of microwell geometry parameters generated from the design of experiments (DOE) software on detected signals using finite element simulation software. The study found that the microwell wall thickness affects the detected current signal most significantly and the optimized geometry that minimally reduces measured current signal was 20 µm height, 5 µm well thickness, and 16 µm gap size.
Searching for the electron/positron pair halo of the Blazar H1426+428 using XMM-Newton
Authors: Kueathan A , Luangtip W , Eungwanichayapant A
Published: December 2019

Electron/positron pair halo is a physical phenomenon in which the very high energy gamma rays emitted from Blazar interact with cosmic infrared background (CIB) so that produce the electron/positron pairs; the produced electron/positron pairs could up-scatter the cosmic microwave background (CMB) reproducing the gamma-rays, thus these form the cascade process of producing the electron/positron pairs appearing as an halo around the blazar. In case that the halo presents in the ambient strong magnetic field, the electron/positron pairs could emit X-ray light via synchrotron process providing another opportunity to detect the halo. In this work, we search for the X-ray emission from the halo of the Blazar H1426+428 using the observed X-ray data from XMM-Newton observatory. The X-ray spectra of the halo are carefully extracted from the annulus, source free regions around the Blazar to avoid the X-ray contaminations from the Blazar itself and the nearby point sources. These spectra were fitted using the physical model which takes into account the emissions from the unresolved cosmic X-ray and instrument backgrounds. The unresolved flux of ≍ 10–13 erg s–1 cm–2 have been detected in the regions, and we argue that, at least, some fraction of the flux might be the emission from the halo.
Simple improvement in latent fingerprint detection with Ninhydrin/water glue on thermal paper
Authors: Eksinitkun G , Pansiw S , Phutdhawong W
Published: December 2019

Thermal paper is a special type of paper that is coated with chemicals on the paper layer to change color when exposed to heat. When discovering fingerprints by using chemical reagents such as ninhydrin solution with thermal paper, it shows black staining background on the heat-sensitive front side. Thus, the latent fingerprints cannot be discovered. In this study, we have reported the first utilization of ninhydrin with water glue in different ratios for the development of latent fingerprints on the thermal papers. The results showed that at 0.020-0.060 g/mL of water glue in ninhydrin solution reduced the black strain after tested with thermal paper and made the appearance of the fingerprint more clearly. So, the detectable minutiae can be used for visualization and identification of latent prints. Using an Automated Fingerprint Identification System (AFIS), it is showed between 59-87 points of minutiae. As the results, this method could be used as an alternative method to developing latent fingerprints with non-hazardous materials, reduce costs and easy to find.
The cancellation of human sounds using synthesized soundwaves
Authors: Srijomkwan K , Weerasakul C , Kittiweerawong S , Puntree J
Published: December 2019

The principle of destructive interference is applied to reduce or eliminate the spoken sound in order to increase speech privacy. This research is divided into two parts: the synthesis of sound from formula, using both analytical linguistics and physical approaches, and the actual cancellation of simple to complex sounds in the real world setting. The results suggested that in a real-world setting, up to 60% intensity reduction could be repeatedly detected. When the complexity of the sound is increased, difference in interference pattern could be detected between sounds in frequency range within the human hearing spectrum. Furthermore, it is found that the generation of negative sound using the four formants is not comprehensive enough to interfere effectively with actual sound, therefore the spectral slice is needed to synthesize more complex sounds. After testing various variations, it is found that using 11 most intense frequency components adjusted in proportion according to each original amplitude best cancel the widest range of human sound samples. This method was used to test the effectiveness of actual human sound cancellation. Though effective cancellation was detected in the high frequencies range of the sound spectrum, other frequency ranges were barely affected. The difference between cancellation patterns of each frequency range might need investigating before the cancellation of human sound can be effectively applied in real life.
Droplet transport from main HT-6M poloidal limiter
Authors: Somboonkittichai Nopparit
Published: December 2019

The HT-6M is a tokamak installed only with a main metallic poloidal limiter, which may not tolerate energy deposition due to a limited plasma-wetted area. This leads to the production of fresh metallic impurities, including macro-particles, in its main vessel. The macro-particles are transported and then ablated far away from where they were created. Understanding transport and ablation is beneficial to characterize impurity generation in the HT-6M, which will be recommissioned in Thailand in the next few years. A computational study simulated the motion of macro-particles in the HT-6M using the specifically written Dust and Droplet Tracking (DDT) code with the steady state HT-6M plasma profiles produced from the Transport Analyzing System for tokamaK (TASK) code. The results showed that a substantial amount of vapor containing impurities in the scrape-off layer (SOL) plasma was produced by the ablation of the liquid macro-particles emitted from the HT-6M poloidal limiter when the macro-particles were located near the limiter and nearby plasma-facing components (PFCs). Heavy ablation on the macro-particles transported directly towards the core plasma led to complete vaporization locally. The updated DDT code is discussed.
Phase transitions in the frustrated antiferromagnetic XY model on the triangular lattice
Authors: Klawtanong M , Srinitiwarawong C
Published: December 2019

Phase transitions and thermodynamics properties of the frustrated antiferromagnetic XY (FAXY) model have been investigated near the two transition temperatures. We found that the Kosterlitz-Thouless (KT) transition corresponding to the rotational U(1) symmetry breaking and the Ising-like (I) transition corresponding to the reflection Z
2 symmetry breaking occur at two-separate transition temperatures, Tkt
< TI
. These temperatures lie close to each other, however in our results the separation is obvious. Our results show the order parameters as a function of temperature and we also estimate the critical exponents, β, α, γ, η and ν. The critical exponent ν indicates that the Ising-like transition is inconsistent with the Ising universality class.
Luminosity function of high-z object candidates at the epoch of reionization (z ≳ 6) in cosmic evolution survey (COSMOS) field
Authors: Thananusak N , Sawangwit U , Wannawichian S
Published: December 2019

The investigation of the luminosity functions (LF) of objects at the epoch of reionization or EoR (z≳ 6) is crucial for placing stronger constraints on the contribution of different ionizing photon sources. In this study, we aim to estimate the luminosity functions ofz≳ 6 candidates. The data catalog obtained from Hyper Suprime-Cam Strategic Program (HSC-SSP) ultra-deep survey data released one and the ultra-deep Visible and Infrared Survey Telescope for Astronomy (UltraVISTA) data released four in optical(rizy)and near-infrared(YJHKs)photometry filters, respectively. We focus the deep survey on Cosmic Evolution Survey (COSMOS) field, centered at RA ∼ 10h00m28.6sDEC ∼ +2°12′21.0″. The 79 candidates are selected by the Lyman Break Galaxies (LBGs) technique withzband drop-out, and photometric redshift approximation (photo-z). We then used the candidates to calculate thez≳ 6 LF. Accordingly, we compare the LF with other works that focus on the high-zobjects at similarz-range.
Investigations of physical and structural properties of calcium alumino silicate glasses doped with samarium (III) oxides
Authors: Suebsing N , Lekkla W , Lhakjun D , Laopaiboon R , Bootjomchai C
Published: December 2019

We synthesized and investigated the physical and structural properties of calcium alumino-silicate glasses systems: (60-x)SiO2–2.5Al2O3–10CaO–17Na2O–10K2O–0.5Sb2O3–xSm2O3. The samples were prepared using melt quenching method. Density was measured using Archimedess principle, and the physical properties such as the ion concentrations, interatomic distance, polaron radius, and field strength were calculated. The density, the calculated ion concentrations, and field strength increased while the interatomic distance and polaron radius decreased with increasing of Sm2O3 contents. The structure of the glasses was characterized using the Fourier transform infrared spectrometer. The FTIR result showed that the change in the network structures of these glasses depends on the concentration of Sm2O3.
Pitch-angle diffusion coefficients in test particle simulations and the estimation of the particle parallel mean free path
Authors: Pleumpreedaporn C , Snodin A P
Published: December 2019

The transport of energetic charged particles in turbulent magnetic fields is a topic of interest in various astrophysical contexts. In order to estimate the mean free path of a particle in the direction parallel to the mean magnetic field, one can use theoretical expressions that employ pitch-angle diffusion coefficients. In this work we review some of the methods used in estimating pitch-angle diffusion coefficients from test particle computer simulations. We examine if these methods and theoretical approaches are able to provide consistent estimates of the parallel mean free path, that can also be obtained directly from computer simulations. We perform test particle simulations for synthetic turbulence models over a range of turbulence parameters and particle energies. From the trajectories of test particles, pitch-angle distribution functions and statistics of pitch-angle displacements are obtained, which are then used to estimate the pitch-angle diffusion coefficients. We find that a method using the pitch-angle flux and derivative of the pitch-angle distribution is able to provide accurate values for the parallel mean free path over the range of parameters considered. Other methods considered are accurate only for a limited range of the turbulent fluctuation strength, or must be evaluated at a specific time to provide a reasonable estimate.
The relationship between raining and GPS – precipitable water vapor
Authors: Choosakul Nithiwatthn , Jaiyen Sarawut , Jairuk Umpon , Authisin Janthanee
Published: December 2019

Precipitable water vapor (PWV) can be retrieved from the delayed of the propagating GPS signal through the wet atmosphere. In the experiment, the GPS data in 2009 from the permanent GPS station name of CUSV were used to estimate the amount of integrated vertical water vapor above the GPS station in term of PWV. The results showed that the PWV were fluctuated all year long with their averaged of 31.05 mm. At the beginning of the year, the PWV were slightly increased until reach a plateau around DOY 120. This plateau was higher than their averaged around 10 mm in six months during the midyear. Then, the PWV gradually decreased until the end of the year. In addition, the strongly relationship between the rainy day and the PWV was found. 95.76 % of total rainy days (165 days) confirmed that the PWV were higher than their averaged. On the other hand, 69.00 % of total non – rainy days (200 days) showed that the PWV were lower than their averaged. Therefore, the PWV can be used as the key indicator of rain prediction.
Upper limits on dark matter annihilation with the teraelectronvolt cosmic ray spectrum of electrons and positrons from DAMPE
Authors: Wechakama Maneenate , Khan Cantlay Brandon
Published: December 2019

We have used teraelectronvolt cosmic ray spectrum of electrons and positrons data from DArk Matter Particle Explorer (DAMPE) to estimate the upper limits on dark matter annihilation. We have created modeled spectrum of electrons and positrons by considering dark matter annihilation into electrons and positrons with different channels. After the production, electrons and positrons can lose their energy by interstellar medium and interstellar radiation field. We have considered loss processes such as inverse Compton scattering, synchrotron radiation and ionization. The upper limits on dark matter annihilation cross-section have been investigated by comparing the model spectrum and observational spectrum. The stringent constraints is from electron-positron channel.
The effects of layer thickness and charge mobility on performance of FAI:MABr:PbI2:PbBr2 perovskite solar cells: GPVDM simulation approach
Authors: Sittirak Maythawee , Ponrat Jiraporn , Thubthong Kanyaporn , Kumnorkaew Pisist , Lek-Uthai Jeerranai , Infahsaeng Yingyot
Published: December 2019

The perovskite solar cells (PSCs) have been extensively interested and its performance has rapidly increased up to 24.2 %. Layer thickness and charge mobility are crucial for high-performance perovskite solar cells. In this paper, we study the effect of layer thickness and charge mobilities on some parameters in perovskite solar cell based on structure of FTO/TiOx/SnO2/FAIMABrPbI2PbBr2/Spiro-OMeTAD/Ag by using the GPVDM (General-purpose Photovoltaic Device Model) software. The simulation results show that the best optimized power conversion efficiency of 23.88 % can be obtained. The optimal layer thickness in the simulation of TiOx, SnO2, FAIMABrPbI2PbBr2, Spiro-OMeTAD are 50 nm, 30 nm, 400 nm, 30 nm, respectively. The optimal electron and hole mobilities of photoactive layer are 2×10-5 m2V-1s-1 and 2×10-6 m2V-1s-1, respectively. Comparative study of simulation and experiment are observed, that performance of 15.93 % of efficiency can be experimentally achieved, however the model of this solar cell is observed 18.43 % of efficiency by simulation.
The effects of dielectric barrier discharge atmospheric air plasma treatment to germination and enhancement growth of sunflower seeds
Authors: Yawirach S , Sarapirom S , Janpong K
Published: December 2019

This research was to study the effectiveness of dielectric barrier atmospheric plasma (DBD) on sunflower seed (Helianthus annuus). The DBD plasma was driven with a power of 90 watts. The samples consisted of five groups; control group, samples 1, 2, 3 and 4 being treated by DBD plasma with time limits of 30 s, 60 s, 90 s and 120 s, respectively. The physical properties and chemical properties were observed using SEM and water contact angle. Growth parameters were studied by the water uptake, seed germination, sprouts length and dry weight. Compared with the control sample the results showed the contact angle decreased and the wettability increased. The surface roughness in all conditions increased with increased power. With bigger power the water absorption decreased and super hydrophilic was achieved with 120 s treatment. The water uptake of plasma produced the best result using the DBD plasma treatment of 120s. The distribution of sprouts length and the dry weight both increased with increased power. The DBD plasma treatment on sunflower seeds improves seed germination rate and lead to a significant change in wettability and growth parameter.
Investigation on current transformers for measuring of electron beam pulse current
Authors: Nanthanasit P , Rimjaem S
Published: December 2019

The radio-frequency (RF) linear accelerator (linac) system of the PBP-CMU Electron Linac Laboratory at the Plasma and Beam Physics Research Facility is used as an injector system for future mid-infrared and terahertz free-electron lasers. The properties of electron beams produced from the linac must be controlled appropriately to produce high-quality radiation. One of the most important properties is the electron pulse current that can be measured using a current transformer. A copper wire with proper insulator is wounded around the ferrite-core forming a secondary coil of the current transformer. The electron beam passing through the transformer acts as the current in the primary coil and it induces an electromotive force in the secondary coil. Therefore, the output signal from the secondary coil can be measured and analyzed to be a pulse current of electron beam. The measured current pulse shape and value strongly depend on the characteristics of the current transformer. This study focuses on testing and calibrating of existing current transformers installed in the linac system. In the experiments, the pulse generator was used to generate the input pulse current with various pulse lengths. The output pulses were then sampled with a digital oscilloscope. The experimental results showed that the output pulses from the current transformers have distort shape compared with the input pulses. Consequently, the correction was conducted to provide more accuracy of the measuring value of the electron pulse current. The results of this research can be used as a valuable database for the existing current transformers and to develop the new ones that can provide more accurate results.